Oct 24, 2015

Experiment tests Einstein's 'God does not play dice' with quantum 'dice'

Random number generators developed at ICFO -- The Institute of Photonic Sciences, by the groups of ICREA Professors Morgan W. Mitchell and Valerio Pruneri, played a critical role in the historic experiment was published online today in Nature by the group of Ronald Hanson at TU Delft. The experiment gives the strongest refutation to date of Albert Einstein's principle of "local realism," which says that the universe obeys laws, not chance, and that there is no communication faster than light.

As described in Hanson's group web the Delft experiment first "entangled" two electrons trapped inside two different diamond crystals, and then measured the electrons' orientations. In quantum theory entanglement is powerful and mysterious: mathematically the two electrons are described by a single "wave-function" that only specifies whether they agree or disagree, not which direction either spin points. In a mathematical sense, they lose their identities. "Local realism" attempts to explain the same phenomena with less mystery, saying that the particles must be pointing somewhere, we just don't know their directions until we measure them.

When measured, the Delft electrons did indeed appear individually random while agreeing very well. So well, in fact, that they cannot have had pre-existing orientations, as realism claims. This behaviour is only possible if the electrons communicate with each other, something that is very surprising for electrons trapped in different crystals. But here's the amazing part: in the Delft experiment, the diamonds were in different buildings, 1.3 km away from each other. Moreover, the measurements were made so quickly that there wasn't time for the electrons to communicate, not even with signals traveling at the speed of light. This puts "local realism" in a very tight spot: if the electron orientations are real, the electrons must have communicated. But if they communicated, they must have done so faster than the speed of light. There's no way out, and local realism is disproven. Either God does play "dice" with the universe, or electron spins can talk to each other faster than the speed of light.

This amazing experiment called for extremely fast, unpredictable decisions about how to measure the electron orientations. If the measurements had been predictable, the electrons could have agreed in advance which way to point, simulating communications where there wasn't really any, a gap in the experimental proof known as a "loophole." To close this loophole, the Delft team turned to ICFO, who hold the record for the fastest quantum random number generators. ICFO designed a pair of "quantum dice" for the experiment: a special version of their patented random number generation technology, including very fast "randomness extraction" electronics. This produced one extremely pure random bit for each measurement made in the Delft experiment. The bits were produced in about 100 ns, the time it takes light to travel just 30 meters, not nearly enough time for the electrons to communicate. "Delft asked us to go beyond the state of the art in random number generation. Never before has an experiment required such good random numbers in such a short time." Says Carlos Abellán, a PhD student at ICFO and a co-author of the Delft study.

Read more at Science Daily

Comet Lovejoy Holds Building Blocks of Life

Scientists on Friday identified two complex organic molecules, or building blocks of life, on a comet for the first time, shedding new light on the cosmic origins of planets like Earth.

Ethyl alcohol and a simple sugar known as glycolaldehyde were detected in Comet Lovejoy, said the study in the journal Science Advances.

“These complex organic molecules may be part of the rocky material from which planets are formed,” said the study.

Other organic molecules have previously been discovered in comets, most recently in comet 67P/Churyumov-Gerasimenko, on which the European space agency’s Philae lander found several organic molecules — including four never detected before on a comet.

Since comets contain some of the oldest and most primitive material in the solar system, scientists regard them as time capsules, offering a peek at how life on Earth started 4.6 billion years ago.

But while the latest study does not end the debate over whether falling comets indeed seeded Earth with the components necessary for life, it does add something to our knowledge, said study co-author Dominique Bockelée-Morvan, an astrophysicist at the French National Center for Scientific Research.

“The presence of a major complex organic molecule in comet material is an essential step toward better understanding the conditions that prevailed at the moment when life emerged on our planet,” she told AFP.

“These observations show a possible explanation for its (life’s) origin on our planet,” she added.

Read more at Discovery News

Oct 23, 2015

Rio Reintroduces Howler Monkeys After Century's Absence

Scientists have given Rio de Janeiro something to shout about with the reintroduction of howler monkeys to the city's famed Tijuca forest after a century's absence.

Tijuca, a thick forest rising up to the towering Corcovado and statue of Christ the Redeemer, is one of the world's largest urban woodlands. But environmental degradation has stripped the area of its fauna.

Now, Brazilian scientists are working to bring those riches back, including by releasing native howler monkeys, properly know as Alouattas.

"The howlers disappeared more than 100 years ago. We decided to reintroduce them because it is a resistant species. They essentially eat leaves and fruits, so they are relatively easy to reintroduce," said Fernando Fernandez, a scientist with the Federal University of Rio de Janeiro.

The first five monkeys were released in early September, a key moment in the program which has been in the works since 2010.

And the creatures are more than just a pretty -- or furry -- face.

In addition to filling the silent forest with their trademark cries, the monkeys' excrement, pushed around by dung beetles, helps fertilize soil and trees.

That's important because the authorities also want to save the endangered Atlantic forest, which once covered the Brazilian coast but today is reduced to about seven percent of what European explorers would have found 500 years ago.

In Rio, the Tijuca forest covers 39.5 square kilometers and has been preserved despite being just minutes from neighborhoods of the teeming city which will host next year's Olympics.

Tijuca administrator Enresto Vivero de Castro says the area can become "a laboratory for the rebuilding of the fauna that could work for other parts of the world."

The first monkeys let loose in Tijuca were all rescued from animal traffickers.

The modest speed of the project reflects the care needed to avoid any monkey business between potentially conflicting groups of the primates.

"The howler is the biggest monkey of the Atlantic Forest after the spider monkey. We got five individuals -- three males and two females -- and before releasing them we let them interact for five months in our research center," Fernandez said.

"It's very important because the Alouattas form social groups and stay together in the forest."

The pioneering animals are already one down from their original number.

The dominant male Chico expelled a young male named Cesar, so researchers pulled him from the project. However, Cesar should get a second chance with another group down the road.

Scientists monitoring the four identify the males by a bracelet and the females by a collar. Early reports are that things are going well.

"A month and a half later they are doing fine and are pretty close to where we released them," Fernandez said.

"There was some concern when the group met some capuchin monkeys, which are more aggressive. But in the end there wasn't a problem."

Read more at Discovery News

Can Crocodiles Sleep with One Eye Open?

Sleep, for animals, can be a dicey proposition. While rest and renewal are necessary, snoozing can leave a creature vulnerable to threats. Some birds and aquatic mammals have adapted the ability to keep half their brain on alert while the other half slumbers, a phenomenon known as unihemispheric sleep -- in essence, sleeping with one eye open.

A new study from researchers out of Australia's La Trobe University and Germany's Max Planck Institute for Ornithology shows that crocodiles may well be taking a page from that book.

The researchers studied juvenile crocodiles (adults would be a bit too dangerous to work with) in a special holding aquarium, with cameras trained on the reptiles for 24 hours at a time.

They tested for use of vigilant, one-eyed sleeping behavior by sending, in turn, another crocodile and a human into the holding area.

Most of the time, particularly at night, the crocodiles slept with both eyes closed. But in both cases -- human or crocodile interloper -- the young test crocs indeed opened one eye and trained it on their new neighbor, appearing otherwise to slumber.

Dolphins, some seals, manatees, and walruses are among those animals that have evolved unihemispheric sleep, in which half the brain, using an electroencephalogram (EEG) test, appears to be sleeping, while the other half shows brain wave activity that looks more like an animal that's awake. The eye corresponding to the awake half can remain open. Some birds species do it too.

But crocodiles have never been studied closely for the behavior.

"These findings are really exciting as they are the first of their kind involving crocodilians and may change the way we consider the evolution of sleep," said the study's lead researcher Michael Kelly, of La Trobe University, in a press release.

Read more at Discovery News

Halloween Asteroid May Actually Be a Comet

The big asteroid that will zoom past Earth on Halloween may actually be a comet, NASA researchers say.

The roughly 1,300-foot-wide (400 meters) asteroid 2015 TB145, which some astronomers have dubbed “Spooky,” will cruise within 300,000 miles (480,000 kilometers) of Earth on Halloween (Oct. 31) — just 1.3 times the average distance between our planet and the moon.

Though 2015 TB145 poses no threat on this pass, the flyby will mark the closest encounter with such a big space rock until August 2027, when the 2,600-foot-wide (800 m) 1999 AN10 comes within 1 Earth-moon distance (about 238,000 miles, or 385,000 km), NASA officials said.

Astronomers plan to beam radio waves at 2015 TB145 on Halloween using a 110-foot-wide (34 m) antenna at NASA’s Deep Space Network facility in Goldstone, California, then collect the reflected signals with the Green Bank Telescope in West Virginia and Puerto Rico’s Arecibo Observatory.

Such work should reveal key details about the space rock’s size, shape, surface features and other characteristics — including, perhaps, its true identity.

“The asteroid’s orbit is very oblong with a high inclination to below the plane of the solar system,” Lance Benner, of NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement.

“Such a unique orbit, along with its high encounter velocity — about 35 kilometers or 22 miles per second — raises the question of whether it may be some type of comet,” added Benner, who leads NASA’s asteroid radar research program. “If so, then this would be the first time that the Goldstone radar has imaged a comet from such a close distance.”

Asteroid 2015 TB145 will be too faint to spot on Halloween with the naked eye, but anyone who’s interested can get a look at the object online, thanks to live telescope views provided by the Slooh Community Observatory and the Virtual Telescope Project.

The Virtual Telescope Project will air a webcast at 8 p.m. EDT on Oct. 30 (0000 GMT on Oct. 31), while Slooh’s broadcast begins at 1 p.m. EDT (1700 GMT) on Oct. 31.

Read more at Discovery News

Hubble Sees 'First Light' Galaxies at Dawn of Time

The Hubble Space Telescope has taken its deepest-yet look into the cosmos to see some of the earliest galaxies that popped into existence only a few hundred million years after the Big Bang.

The international team that made the discovery also report these tiny primordial galaxies, which are estimated to have formed only 600 million years after the universe came into existence, played an intrinsic role in shaping the cosmos, burning away the smoggy remnants of hydrogen gas that would have blotted out many of these galaxies from view.

These galaxies are therefore giving us a very privileged glimpse into the universe just at the end of the mysterious “re-ionization epoch,” which is thought to have ended around 700 million years after the Big Bang.

To acquire these record-breaking images, Hubble used a neat cosmic trick to boost its magnification. Gravitational lensing is caused by massive clusters of galaxies warping spacetime. Any more distant sources of light, like these newly discovered primordial galaxies that would normally be too faint to see with Hubble’s lens, are boosted through gravitational lensing, allowing astronomers to look deeper into the universe than ever before.

“The faintest galaxies detected in these Hubble observations are fainter than any other yet uncovered in the deepest Hubble observations,” said astronomer Johan Richard from the Observatoire de Lyon, France.

These observations of around 250 previously unseen galaxy comes as a result of the Hubble’s Frontier Fields program that is using gravitational lensing to superboost the space telescope’s capabilities. Often, the images of distant lensed galaxies are seen as arcs, or in very rare cases, complete circles (such as Einstein Rings — where the galactic light is completely warped into a full circle around the lensing galactic cluster).

“Clusters in the Frontier Fields act as powerful natural telescopes and unveil these faint dwarf galaxies that would otherwise be invisible,” said co-author Jean-Paul Kneib, from the Ecole Polytechnique Fédérale de Lausanne, Switzerland.

This groundbreaking observation comes over 25 years since Hubble was launched in 1990, and yet it is still breaking new barriers that no other observatory can currently accomplish.

Read more at Discovery News

Oct 22, 2015

Weird Pig-Nosed Turtle from Dinosaur Era Found in Utah

"It's one of the weirdest turtles that ever lived."

That was the assessment of University of Texas at Austin doctoral student Joshua Lively, in a statement about a strange new species of turtle that had a pig-like nose and lived 76 million years ago.

A fossil of the strange animal was first discovered in Utah's Grand Staircase-Escalante National Monument, by scientists from the state's natural history museum. The bones, under study by Lively during master's work at the University of Utah, suggest a two-foot-long creature with a feature never before seen in a turtle: two bony nasal openings.

Every other known turtle has just one nasal opening in its skull, the discrete nostrils created by a fleshy division.

The turtle -- dubbed Arvinachelys goldeni -- lived during the Cretaceous, among tyrannosaurs, armored ankylosaurs, and other dinosaurs in a southern "Utah" that would more closely have resembled the wet, hot landscape of bayous and rivers of present-day Louisiana.

As studies continue, the new fossil should help fill gaps in our understanding of turtle evolution, scientists say. Typically, turtle fossils don't offer much more than a skull or a shell. But the pig-nosed turtle remains have those plus an almost complete forelimb, partial hind limbs, and vertebrae from the neck.

"With only isolated skulls or shells, we are unable to fully understand how different species of fossil turtles are related, and what roles they played in their ecosystems," said Randall Irmis, curator of paleontology at the museum and associate professor at the University of Utah.

Lively has just described the new species in a paper in the Journal of Vertebrate Paleontology.

From Discovery News

Plague DNA Detected in Bronze Age Teeth

Plague is a disease that conjures a mix of horror and revulsion at its mere mention because of the mark it has left on human history. Plague wiped out entire regions, triggered economic and political collapse, and threatened Western civilization on more than one occasion.

As much of an impact plague has had over the course of millennia, The bacterium that causes plague infections, Yersinia pestis, has been haunting humans even longer than once thought, report scientists in the journal Cell. In fact, Y. pestis was common as far back as the Bronze Age.

For their study, a team of researchers drawn from a network of European academic institutions sequenced the DNA from the teeth of Bronze Age 101 individuals from Europe and Asia. What they found was a common ancestor to Y. pestis dating back 5,783 years.

“Our findings suggest that the virulent, flea-borne Y. pestis strain that caused the historic bubonic plague pandemics evolved from a less pathogenic Y. pestis lineage infecting human populations long before recorded evidence of plague outbreaks,” the authors wrote in their journal article.

Prior to the evolution of later strains of Y. pestis, this ancestral strain lacked two key weapons in its genetic arsenal.

Bronze Age Y. pestis lacked a gene called Yersinia murine toxin (ymt). Ymt allows the bacteria to survive in the gut of a flea, a critical disease vector. Beginning between 3,700 and 3,000 years ago, this gene turns up in the DNA of Iron Age individuals, which suggests human transmission was possible in that era.

A second mutation not seen in Bronze Age Y. pestis directly affects the ability of the bacteria to cause bubonic plague. The gene pla facilitates deep tissue invasion, which allows the plague to travel into the lymph nodes, weakening the host’s immune response and permitting widespread tissue damage. One of the most apparent symptoms of bubonic plague infection is swollen and tender lymph nodes, known as buboes.

Just because Bronze Age individuals didn’t contract bubonic plague doesn’t mean they weren’t deathly ill. Y. pestis also leads to pneumoic plague, a disease of the lungs passed on through human-to-human contact by inhaling droplets coughed by an infected person.

Pneumonic plague is the deadliest disease variant triggered by Y. pestis. At its worst, it leads to bloody mucus, respiratory failure and shock, with the infected individual eventually coughing violently to death. Even today, the mortality rate for this disease stands at nearly 100 percent if antibiotics aren’t administered within 24 hours of infection. And even with the best of modern medicine, the person only has a 50-50 shot at survival.

The Bronze Age also happened to be a period of mass migration and intermixing among disparate populations, previous studies have shown. “In light of our findings, it is plausible that plague outbreaks could have facilitated — or have been facilitated by — these highly dynamic demographic events,” the authors write.

Understanding how Y. pestis became the potent such an effective killer provides insights into the evolution as disease as well as additional history on the plague itself.

Following the Bronze Age, a more evolved strain of Y. pestis left its mark on human events. In the sixth century, the Justinian plague was followed up by frequent bouts of bubonic plague for two centuries that claimed an estimated 25 million lives, notes the Centers for Disease Control and Prevention (CDC).

Read more at Discovery News

No Purpose for Vestigial Ear-Wiggling Reflex

Around the human ear are tiny, weak muscles that once would have let evolutionary ancestors pivot their ears to and fro. Today, the muscles aren’t capable of moving much — but their reflex action still exists.

These muscles are vestigial, meaning they’re remnants of evolution that once had a purpose but no longer do. However, humans may be able to repurpose these useless muscles for their own uses, according to Steven Hackley, a psychologist at the University of Missouri and author of a new review of research on the forgotten muscles in the journal Psychophysiology.

For one, these muscles activate in response to positive emotions, for reasons nobody truly understands. This odd fact creates a handy tool for psychologists seeking an objective way to measure emotion.

And then there are the educational implications: This muscle reflex is new evidence against the notion of creationism or intelligent design, Hackley said.

“According to intelligent design and creationism, our body was designed by a being with perfect intelligence,” he said. “If that were the case, why would he put circuits in our brains that don’t work? Why would you put circuits in our brain which are useful for lemurs that are useless for humans?”

Mysterious muscles

Another question: Why study these useless muscles at all?

The use of tiny muscle responses to study emotions goes way back, Hackley said. Researchers have found that people have an elevated “startle” response — measured by the twitching of muscles below the eye — when they’re experiencing a negative mood rather than a positive mood. This makes sense, he said, if you think about watching a horror movie late at night and hearing a sudden crash from outside. You’re likely to be far more spooked than if you’d been watching a romantic comedy.

About a decade ago, psychologists tried to find this same response in the vestigial auricularis posterior muscle, which sits right behind the ear and attaches at the ear’s base. Unexpectedly, the auricularis posterior doesn’t respond more strongly when a person is in a bad mood; instead, its response is strongest when people are at their happiest.

“This doesn’t make sense,” Hackley said. “There’s nothing intuitive about it.”

Even in people capable of wiggling their ears, the auricularis posterior reflex is too weak to actually move the ear. At first, Hackley said, researchers thought this muscle’s engagement during happiness had to do with nursing: Perhaps some ancestor’s infants learned to pull their ears back and out of the way while suckling, thus associating the muscle movement with the pleasure of food.

But experiments found no evidence for this nursing hypothesis. Now, Hackley is looking in a different direction. The tiny ear muscles are linked to the facial muscles that pull the mouth into a smile, he said — grin big, and you’ll feel your ears retract. Perhaps the feeling of happiness primes the smile muscles for action, including the useless auricularis posterior.

Whatever the reason for this odd muscle activation, it’s useful for psychologists. Self-reported emotion questionnaires can be inaccurate if people lie or aren’t even aware of subtle emotions. Muscle responses don’t like.

The person can’t fake it,” Hackley said.

Unintelligent design

There’s another, perhaps more provocative implication to these pointless ear muscles, Hackley said: They’re evidence against intelligent design.

In the battle over evolution, creationists and believers in an intelligent designer often claim that so-called vestigial organs have a purpose. And in many cases, they do. The appendix, for example, was long thought to be an intestinal dead end before scientists found that it can protect helpful bacteria during illness, allowing the useful microbes to repopulate the gut.

Read more at Discovery News

Dead Man Punching Sheds Light on Fist Evolution

Human hands evolved, at least in part, for fighting, with a surprising new study that involved using cadaver arms and fists.

Researchers used actual cadaver arms to punch and slap padded dumbbells in experiments that provide evidence in favor of the hotly debated theory that humans, and especially men, are hardwired both mentally and physically to fight at times. The findings are reported in the Journal of Experimental Biology.

“The idea that aggressive behavior played a role in the evolution of the human hand is controversial,” explained senior author David Carrier in a press release.

“Many skeptics suggest that the human fist is simply a coincidence of natural selection for improved manual dexterity,” added Carrier, who is a biology professor at the University of Utah. “That may be true, but if it is a coincidence, it is unfortunate.”

“As an alternative,” he continued, “we suggest that the hand proportions that allow the formation of a fist may tell us something important about our evolutionary history and who we are as a species. If our anatomy is adapted for fighting, we need to be aware we always may be haunted by basic emotions and reflexive behaviors that often don’t make sense — and are very dangerous — in the modern world.”

Carrier and his team used nine male cadaver arms for the study. The arms from the deceased were purchased from the university’s body donor program and from a private supply company.

The scientists tested the hypothesis that a clenched fist protects the metacarpal (palm or hand) bones from injury and fracture by reducing the level of strain during striking. To do this, they placed each of the cadaver arms in a pendulum-like apparatus that enabled the arms to swing toward, and punch, a padded, force-detecting dumbbell.

“Metacarpals are bones in the hand that break most often — not finger bones, but bones of the palm,” Carrier said. “When guys get mad and punch a wall, or when bars close and they punch each other, the bones that break most often are the metacarpals.”

The scientists caused the arms and hands to punch with either a clenched/buttressed fist, where the thumb is locked around the index and middle fingers, which are curled tightly to the palm; or with an unbuttressed fist, where the thumb is outward and not touching the loosely folded fingers. The researchers also caused the arms to side-slap the target with an open hand.

After hundreds of punches and slaps using eight of the arms (one was too arthritic), the researchers determined that humans can safely strike with 55 percent more force with a fully buttressed fist than with an unbuttressed fist, and with twofold more force with a buttressed fist than with an open hand slap.

Read more at Discovery News

Two Monster Stars 'Kiss' Before Doom

Deep inside the Tarantula Nebula, some 160,000 light-years from Earth, live a pair of very strange stars.

The two young stars form one of the most extreme stellar binaries yet found — they orbit one another in less than a day. Their orbital embrace is so extreme in fact, that they are embracing; super-heated plasma from their photospheres are physically mixing from one lobe to the other.

The binary pair, called VFTS 352, was discovered by the European Southern Observatory’s Very Large Telescope, which was used to peer deep inside the nebula’s star-forming nursery. From these observations, astronomers have found that the hot, bright stars’ plasma is overlapping, forming a bridge between the two masses. Their centers are only 12 million kilometers (7.5 million miles) apart.

Known as an “overcontact binary” this bizarre object has a very dramatic future ahead of it. Not only is it the most massive overcontact binary known (with a combined mass of 57 times the mass of the sun), it is also the hottest, burning away with a surface temperature of 40,000 degrees Celsius (or Kelvin).

Usually, compact binary stars consist of a smaller star with a more massive partner. In this case, the more massive star’s gravity pulls matter from its partner — hence the moniker “vampire stars”. But VFTS 352 is different; both components are of identical mass, so one star isn’t preferentially beefing up on the other’s plasma. Astronomers estimate that the pair are actually sharing up to 30 percent of each other’s plasma.

“The VFTS 352 is the best case yet found for a hot and massive double star that may show this kind of internal mixing,” said Leonardo A. Almeida, of the University of São Paulo, Brazil, and lead author of a new paper published in the Astrophysical Journal. “As such it’s a fascinating and important discovery.”

Although both components of this massive object are existing in relative harmony for now, that’s going to change very soon. According to Almeida’s team, both stars will either merge, creating one, massive, fast-spinning star, or alternatively both may go supernova, ultimately creating an extreme black hole binary system.

Read more at Discovery News

Oct 21, 2015

What Food Tastes Like to a Cat

Cats have a much more refined sense of taste than previously thought, with new research showing that felines are highly sensitive to bitter flavors.

The discovery could help explain why cats so often turn up their noses at certain foods that may be fortified with bitter-tasting vitamins and minerals. The findings, published in the journal PLOS ONE, also provide intriguing clues on how sense of taste evolved in all mammals, including humans.

“Cats are known as picky eaters,” said Monell Center molecular biologist and study lead author Peihua Jiang. “Now that we know that they can taste different bitters, our work may lead to better formulations of cat food that eliminate the bitter off-taste associated with certain flavors and nutrients.”

For the study, Jiang and colleagues examined DNA from domestic cats and identified 12 different genes for cat bitter receptors. The scientists then probed the receptor cells to see if one or more of 25 bitter-tasting chemicals activated them.

The researchers confirmed that at least seven of the identified 12 receptors did indeed have the ability to detect one or more bitter chemicals. It is likely that the other five receptors have this ability too, but that they may respond to bitter compounds not included in this particular study.

Prior research determined that cats are unable to detect sugars. Other carnivores, such as sea lions and spotted hyenas, also lost their ability to taste sweet things. These mammals might have a heightened ability to detect salty and savory flavors.

Cats also seem to go for calorie-dense foods and foods with different textures, helping to explain why savory cat treats with slightly crunchy exteriors and soft interiors appear to be a universal feline fave.

A long-standing theory has held that the ability to taste bitter flavors evolved to protect humans and other animals from ingesting poisonous plants. That is now being questioned since, aside from the occasional chomping on kitty grass, cats go for meat and not plant products.

“Alternate physiological roles for bitter receptors may be an important driving force molding bitter receptor number and function,” co-author Gary Beauchamp said. “For example, recent Monell-related findings show that bitter receptors also are involved in protecting us against internal toxins, including bacteria related to respiratory diseases.”

Read more at Discovery News

Marble Medusa Head Found in Ancient Roman Ruins

In the ruins of a Roman city in southern Turkey, archaeologists have discovered a marble head of Medusa, somehow spared during an early Christian campaign against pagan art.

The head was unearthed at Antiochia ad Cragum, a city founded during the first century, around the rule of Emperor Nero, that has all the marks of a Roman outpost —bathhouses, shops, colonnaded streets, mosaics and a local council house.

With serpents for hair, wide eyes and an open mouth, Medusa was a mythical monster who could turn a person to stone with her gaze. At Antiochia, a Medusa architectural sculpture would have served an apotropaic function, intended to avert evil —but later, her likeness would have been considered idolatrous by the Christians who came to live at the site.

“The people living at Antiochia later were zealous Christians who were destroying art in much the same way that ISIS is destroying remnants of the ancient past,” Michael Hoff, a University of Nebraska–Lincoln art historian and director of the excavations, told Live Science. “These things were meant to be destroyed and put into a lime kiln to be burned and turned into mortar.”

Antiochia, which covers more than 7 acres (3 hectares), is located on the sparsely populated outskirts of the town ofGazipa?, atop craggy cliffs in an area that is today dominated by wheat fields. Little is known about the city from ancient sources, and though the archaeological site had been identified in the early 19th century, it had never been given much attention by scholars until recently, Hoff said.

“The fact that it’s somewhat of an unknown city makes it fascinating for us as archaeologists,” he added. The evidence Hoff and his colleagues have dug up so far suggests Antiochia might have actually been an economic player during the Roman Empire, a center for the trade and production of wine, agriculture and glass.

“The result of all this economic activity is a pretty high degree of cultural output,” Hoff said. In 2012, they discovered an enormous poolside mosaic covering 1,600 square feet (150 square meters) with intricate geometric patterns. They also found the marble head of an Aphrodite sculpture in 2013.

Read more at Discovery News

Male and Female Hearts Age Differently

Men and women will always have their differences, but a new analysis finds that these differences extend to heart anatomy.

The "hearty" differences became apparent only after researchers studied nearly 3,000 adults for about 10 years. By the end of the study, published online today (Oct. 20) in the journal Radiology, the researchers found that male and female hearts grow differently over time.

The study focused on one heart chamber, the left ventricle, which pumps oxygenated blood out of the heart into the body. As people age, the left ventricle declines in its capacity to pump blood.

But the researchers found that this decline happens differently depending on a person's sex: In men, the heart muscle around the chamber grows larger and thicker with age, while in women the muscle maintains its size or gets smaller, the researchers found.

It's unclear why these sex-based differences occur, but this "fascinating discrepancy" may help researchers determine whether gender-specific therapies are necessary for men and women who have heart problems, the researchers said.

"Our results are a striking demonstration of the concept that heart disease may have different pathophysiology in men and women, and of the need for tailored treatments that address such important biologic differences," senior study author Dr. João Lima, a professor of medicine and radiological science at the Johns Hopkins University School of Medicine in Baltimore and director of cardiovascular imaging at the school's Heart and Vascular Institute, said in a statement.

The study is the first long-term research using MRI scans to observe left ventricle structure and function over time, the researchers said. Other researchers have examined people's hearts using ultrasound scans, but MRI scans are more detailed, the researchers in the new study said.

The study included 2,935 adults ages 45 to 84 years. None of the participants had cardiovascular diseases when they enrolled in the study. The doctors performed an MRI scan on each participant at the beginning and end of the study.

From the scans, the doctors assessed the size and volume of the participant's left ventricle, and calculated its weight.

Over the study period, the left ventricle in men gained an average of 0.3 ounces (8 grams). In contrast, it lost an average of 0.06 ounces (1.6 grams) in women, the researchers found.

Moreover, the heart's filling capacity (the amount of blood the left ventricle can hold between heartbeats) fell in both sexes. But this was more pronounced in women, with a drop of about 0.4 fluid ounces (13 milliliters), compared to just under 0.3 fluid ounces (10 mL) in men.

These differences emerged even after the researchers controlled for body weight, blood pressure, cholesterol levels, exercise levels and smoking.

These sex-related differences suggest that "men and women may develop disease for different reasons," said lead investigator Dr. John Eng, an associate professor of radiological science at Johns Hopkins.

Read more at Discovery News

Caught in the Act: White Dwarf is Killing a Planet

Like any crime scene, there's forensic evidence that can be used to work out who committed the deed and how it was done. This goes for "crimes" on a cosmic scale too; particularly when a planet is being ripped to shreds by its host star.

During observations of the white dwarf WD 1145+017, astronomers headed by Andrew Vanderburg, of the Harvard-Smithsonian Center for Astrophysics (CfA), Cambridge, Mass., noticed the presence of several planetary pieces in orbit. They were detected by the Kepler space telescope (that is currently in its "K2" mission phase) and the total mass of debris is thought to be around the size of giant asteroid Ceres that is located inside our solar system's main asteroid belt.

These small planetary husks, all having orbits of between 4.5 to 4.9 hours, are too small to be seen by themselves; but their presence became known when the researchers detected huge dust clouds trailing them in their orbits. Follow-up observations by ground-based observatories were used to decipher what elements are inside the debris.

These dusty trails are accompanied by a debris disk surrounding WD 1145+017 and the dust contains magnesium, aluminium and silicon. And it's these elements that form the evidence for the white dwarf's "planetary murder" -- they are the ingredients for a small rocky planet, a planet that is being ripped apart and pounded to dust. This is the first time a white dwarf has been "caught in the act" of destroying its planetary system.

"This is something no human has seen before," said Vanderburg in a CfA news release. "We're watching a solar system get destroyed."

A white dwarf forms after a main sequence star, like our sun, runs out of fuel. The star puffs up into a red giant and then violently sheds its outer layers as powerful stellar winds. The resulting planetary nebula leaves a small white dwarf star in its wake.

For any surviving planets, life around a white dwarf star is harsh. If a planet or asteroid drifts too close, the star's intense tides can rip any rocky body to pieces, creating a dusty envelope of destruction.

Heavy elements like the ones found around WD 1145+017 should fall into the star pretty quickly -- they have short "settling times" according to astronomers -- so the fact that these elements are still in orbit suggests they were deposited there fairly recently (within the past million years), a sign that a rocky planetary body (or bodies) is being pulverized to dust by the star's tidal forces right now.

Dusty white dwarfs have been studied before, and there has been circumstantial evidence that this dust has come from pulverized planets, but this is the first time a planetary body has been seen in orbit around a white dwarf while being destroyed.

"We now have a 'smoking gun' linking white dwarf pollution to the destruction of rocky planets," added Vanderburg.

Read more at Discovery News

Earth Bloomed Early: A Fermi Paradox Solution?

Our place in the universe is a conundrum — life on Earth evolved to create a technologically-savvy race that is now looking for other technologically-savvy intelligences populating our galaxy. But there’s a problem; it looks like humanity is the only “intelligent” species in our little corner of the universe — what gives?

This question forms the basis of the Fermi Paradox: given the age of the universe and the apparent high probability of life evolving on other planets orbiting other stars, where are all the smart aliens?

According to a new study based on data collected by the NASA/ESA Hubble Space Telescope and NASA’s Kepler Space Telescope, it might be that Earth (and all life on it) is an early bloomer. By extension, the logical progression from this new study is that we’re not hearing from advanced alien civilizations because, in short, the universe hasn’t had the time to spawn many more habitable worlds.

The study, which focuses purely on the likelihood of the evolution of habitable worlds (and not speculation of alien intelligence, the Fermi Paradox implication is my own), finds that when our planet was born from our young sun’s protoplanetary disk some 4.6 billion years ago, it was born into an era when only “8 percent of the potentially habitable planets that will ever form in the universe existed.” This means that the universe has 92 percent to go until it runs out of the necessary material to produce the stars that go on to produce planets, some of which will be small and rocky and orbit in just the right location for life (as we know it) to thrive.

“Our main motivation was understanding the Earth’s place in the context of the rest of the universe,” said Peter Behroozi of the Space Telescope Science Institute (STScI) in Baltimore, Md., “Compared to all the planets that will ever form in the universe, the Earth is actually quite early.”

Hubble has shown astronomers that young galaxies were churning out stars at a fast rate some 10 billion years ago. However, the quantity of hydrogen and helium involved in stellar production was low compared with the amount of these star-forming gases that exist today.

“There is enough remaining material (after the Big Bang) to produce even more planets in the future, in the Milky Way and beyond,” said Molly Peeples, also of STScI.

By combining this knowledge from Hubble with exoplanetary data from Kepler, the researchers were able to form a picture of the habitable planet potential of our galaxy and use it as a model for the number of other habitable worlds existing throughout the cosmos.

Since Kepler started taking data in 2009, we’ve been introduced to a menagerie of small rocky worlds orbiting sun-like stars. Some of these thousands of worlds orbit their stars within the habitable zone — the region surrounding a star that’s not too hot and not too cold to allow liquid water to persist on its surface. By extrapolating from Kepler’s comparatively small dataset, astronomers have predicted that there should be around 1 billion Earth-sized worlds orbiting within their stars’ habitable zones in the Milky Way. If we consider there are 100 billion galaxies in the observable universe, there’s a huge number of habitable, Earth-sized worlds throughout the cosmos.

And the universe, according to this new theoretical study, has only just started in the planetary production business. The last star isn’t expected to fizzle out for another 100 trillion years (when the universe will continue toward its perpetual march to “heat death”), so there’s lots of time left.

With the help of these observations, the researchers predict that Earth 2.0 (i.e. rocky planets of Earth-like dimensions orbiting within their stars’ habitable zones) will most likely pop up inside giant galaxy clusters or dwarf galaxies where reservoirs of star-forming (and therefore planet-forming) gases are known to reside. Alas, the Milky Way’s planet-forming days are numbered, as much of these gases have already been consumed during our galaxy’s heady “starburst” days.

Noted by the researchers is that the advantage of being an “early” civilization evolving at this time of universal evolution is that we have the awesome opportunity to study the early stages of cosmic evolution, using space telescopes (such as Hubble) to see the early formation of galaxies and witness observable evidence for the Big Bang. For any future civilization in a trillion years time, the universe will look very different than it does now — fewer galaxies will be visible and the earliest evidence for the Big Bang (such as the cosmic microwave background radiation) will have further ebbed away.

It’s interesting to ponder how an intelligent alien civilization will interpret a more mature, perpetually expanding universe lacking the cues to its origin that we take for granted today. Would they assume, lacking contradictory evidence, that the universe has always existed? And that just because the universe is expanding, it doesn’t mean there had to be a Big Bang?

Read more at Discovery News

Oct 20, 2015

First Dogs as Pets May Have Come from Nepal, Mongolia

Dogs may have become man's best friend in Central Asia, specifically in what is modern day Nepal and Mongolia, a new genetic study suggests.

Dogs evolved from Eurasian grey wolves at least 15,000 years ago, but just where and how they made the historical leap from roving in packs to sitting before human masters has been a matter of debate.

Aiming to resolve a long-standing mystery about where dogs were first domesticated, the study published in the Proceedings of the National Academy of Sciences is the "largest-ever survey of worldwide canine genetic diversity," said scientists.

The international team, led by Adam Boyko at Cornell University, analysed more than 185,800 genetic markers in some than 4,600 purebred dogs of 165 breeds, along with more than 540 village dogs from 38 countries.

They found that dogs from East Asia, India and South-West Asia had high levels of genetic diversity.

"We find strong evidence that dogs were domesticated in Central Asia, perhaps near present-day Nepal and Mongolia," the scientists wrote.

"Domestic dogs may have originated in Central Asia and spread to East Asia and beyond."

Some archaeologists have long believed Central Asia was a likely origin for domestication of dogs, but genetic studies have been lacking.

Read more at Discovery News

Bloody Arrowhead Reveals Maya 'Life Force' Ceremony

An ancient arrowhead with human blood on it points to a Maya bloodletting ceremony in which a person’s “life force” fed the gods, two researchers say.

The ceremony took place around 500 years ago in Guatemala at a temple at the site of Zacpetén. During the ceremony someone was cut open — possibly through the earlobes, tongue or genitals — with an arrowhead made of obsidian (a volcanic glass), and their blood was spilled.

The Maya believed that each person had a “life force” and that bloodletting allowed this life force to nourish the gods. “The general consensus (among scholars) is that bloodletting was ‘feeding’ the gods with the human essential life force,” said Prudence Rice, a professor emeritus at Southern Illinois University in Carbondale.

“We know Mayas also participated in bloodletting as a part of birth or coming-of-age ceremonies,” said Nathan Meissner, a researcher at the Center for Archaeological Investigations at Southern Illinois University. “This practice served to ensoul future generations and connect their life force to those of past ancestors.”

Whoever gave their blood may have done so voluntarily and probably survived the ceremony, Rice said.

Bloody finds

This life force ceremony was one of many discoveries made in a study published recently by Meissner and Rice in the Journal of Archaeological Science. For the study, they examined 108 arrowheads from five sites in the central Petén region of Guatemala. All the sites had been excavated within the last 20 years and all the arrowheads date to between A.D. 1400 and A.D. 1700.

Using a technique called counter-immunoelectrophoresis they were able to detect the remains of ancient blood on 25 of the arrowheads and identify the types of species they came from. Two of the arrowheads had human blood, while the others held blood from a mix of animals, including rodents, birds, rabbits and large cats.

During the lab procedure, proteins are removed from the arrowheads and tests are conducted to see if the proteins react to serums containing the antibodies of different animals. If a reaction occurs, then it means the proteins from the arrowhead may be from the animal whose antibodies are being tested.

This technique “has been used occasionally in the last decade, but has some limitations because of cost, its potential for contamination, and its success rate,” Meissner said. Quite often, ancient proteins don’t survive the passage of time and the reactions don’t always allow scientists to identify the precise species. For instance, while the researchers were able to tell that four of the arrowheads were coated with the blood of rodents, they couldn’t identify what type of rodents were killed.

Combat casualty?

In the study, the researchers found that two arrowheads had human blood on them. The second arrowhead with human blood was discovered inside an old house near a fortification wall at Zacpetén. Impact damage on the arrowhead suggests it hit a person.

The researchers aren’t clear on the story behind this arrowhead. A wounded individual (perhaps someone who was defending the site) may have been carried into the house, where the arrowhead was removed. “There are multiple accounts of Mayas surviving arrow injuries, which could mean they were brought back embedded in living individuals,” Meissner said.

Read more at Discovery News

Wormhole Wonders: Hunting Down Spacetime Shortcuts

Science fiction literature is full of stories in which tunnels in space-time — known as wormholes — are used for time travel. How much fact lies within the fiction? The answer is, more than you might think. Scientists are looking at ways to use traversable wormholes (if they exist) to travel faster than the speed of light — and even to travel through time itself.

"A traversable wormhole is a hyperspace tunnel, also called a throat, that connects together two remotely distant regions within our universe, or two different universes — if other universes exist — or two different periods in time, as in time travel, or different dimensions of space," physicist Eric Davis told Space.com by email.

Davis specializes in the field of space-time as a member of the Tau Zero Foundation, where he uses equations from Einstein's general theory of relativity to think about possible (or impossible) designs for traversable wormholes, warp drives and time machines.

Building a Wormhole

Wormholes were first proposed in 1916 by mathematician Ludwig Flamm, who was toying around with equations from Einstein's theory of general relativity that describe how gravity can curve space-time, which refers to the fabric of physical reality. While these tunnels through space-time are a fascinating theoretical possibility, according to physicist Kip Thorne, a professor emeritus at the California Institute of Technology, scientists have not yet come up with an agreed-upon way that wormholes could form in nature, and no wormholes have ever been detected.

Thorne and some of his colleagues also showed that even if a wormhole appeared, it would likely collapse before an object (or person) could pass through it. To keep the wormhole open long enough to traverse it would require some kind of scaffolding, but normal matter wouldn't stand up to the job — it would require an "exotic material."

"Dark energy is one form of naturally occurring exotic matter whose negative pressure produces the gravitationally repulsive force that pushes the space inside our universe outward, thus producing the inflationary expansion of the universe," Davis said.

Along with dark energy, scientists also know of an exotic material called dark matter, which is five times more prevalent in the universe than regular matter. To date, scientists have been unable to directly detect either dark matter or dark energy, so much about them is still unknown. Scientists can learn about these materials, though, by examining the effect they have on the space around them.

According to Ali Övgün of Eastern Mediterranean University in Cyprus, it's possible that wormholes could form where dark matter is present, and thus that they could exist in the outer regions of the Milky Way, where dark matter lies, as well as within other galaxies. Övgün is working to prove that wormholes could exist in regions dense with dark matter. He and his colleagues have run simulations that show that wormholes in dense regions of dark matter found in galactic halos would satisfy the physical requirements scientists think the tunnels require.

"But it is only mathematical proof," Övgün said. "I hope one day it will be possible to also find direct experimental evidence."

So, what happens to a person or instrument traveling through a wormhole?

"Nothing! The space-time geometry of traversable wormholes requires that there be no nasty, intolerable gravitational tidal forces acting upon the spacecraft or its passengers while they move through the wormhole tunnel," Davis said. "They go into the throat at their departure location near Earth and get shunted through the tunnel to emerge out the other side near the destination star."

Because these theoretical tunnels cut through space-time, they would allow travelers to achieve speeds that appear to an outside observer to be faster than light (FTL). However, from the travelers' points of view, they would never actually outpace the speed of light — it would just seem that way to outside observers because the travelers would be taking a route that's shorter than they would have taken through ordinary space.

Before scientists could use wormholes, they would first have to find them. To date, wormholes have not been discovered. However, if they exist, locating a tunnel through space-time may not be as difficult as it sounds.

"As it is visualized in the movie 'Interstellar,' in the future, there will be some experiments to observe indirectly," Övgün said.

Based on certain wormhole theories, he compared peering through a wormhole to Alice's glimpse through the looking glass, in Lewis Carroll's novel of the same name. The region of space at the far end of the tunnel should stand out from the area around the entrance thanks to distortions that would be similar to the reflection in curved mirrors. Another indication may be the way light is concentrated as it moves through the wormhole tunnel, much as the wind blows through a physical tunnel.

Davis refers to what is seen at the near end of a wormhole as a "rainbow caustic effect." Such effects could be seen from a distance.

"Astronomers were planning to use telescopes to hunt for these rainbow caustics as a sign of a naturally occurring, or even an alien-made, traversable wormhole," Davis said. "I never heard if that project got off the ground."

Traveling Through Time

As part of his study of wormholes, Thorne also proposed a thought experiment in which a wormhole could be used as a time machine. Thought experiments about time travel often run into paradoxes. Perhaps the most famous of these is the grandfather paradox: If an explorer went back in time and killed his or her grandfather, that person could not be born, and would never have gone back in time in the first place. This seems to suggest that backward time travel is impossible, but according to Davis, Thorne's work opened up a new avenue for scientists to explore.

Read more at Discovery News

These Bacteria Could Live in Europa's Ocean

The idea of life existing in a buried sea inside a moon of Jupiter may seem strange, perhaps impossible. But a series of laboratory tests show that some terrestrial bacteria would adapt well to the salty and sulfate-rich ocean believed to exist beneath the hard icy shell of Europa.

In addition to a global liquid ocean, Europa, which is about one-quarter the diameter of Earth, has a metal-rich core and rocky interior, providing both the chemistry and possible energy sources to support life.

Measurements from NASA's Galileo mission to Jupiter indicate that Europa's ocean is rich in magnesium sulfate, among other salts. That got scientists curious about how well some bacteria that live in harsh environments on Earth would fare under even more extreme conditions that may exist on Europa.

Astrobiologist Sandra Ramirez, with Mexico's Universidad Autonoma del Estado de Morelos, and colleagues tested three strains of bacteria -- Bacillus pumilus, Halomonas halodurans and Salinibacter ruber -- under different concentrations of sodium chloride, magnesium chloride, sodium sulfate and magnesium sulfate.

The point of the experiment was to demonstrate whether the bacteria have the ability to grow not only in the presence of salty sodium chloride, but also but when "salts of astrobiological interest," as Ramirez puts it, are added.

The researchers found that all three strains of bacteria could adapt to a concentrated saline environment. But one, the extremophile Salinibacter ruber, showed a particular fondness for magnesium sulfate. "We found a very different behavior in the extreme bacteria," Ramirez said at the International Astronautical Congress in Jerusalem. "We're conducting experiments investigating the reason for this."

The initial experiments show that Europa's ocean may harbor life as we know it, despite a myriad of potentially extreme conditions, such as temperature, acidity, pressure and salinity, the researchers conclude.

Read more at Discovery News

Oct 19, 2015

Is Sitting Really That Bad? Yes.

Like smoking and overeating, sitting has joined the list of behaviors that seem likely to lead to an early death. In recent years, dozens of studies have linked prolonged sitting with higher risks for cardiovascular disease, cancer, type 2 diabetes and more.

A welcome dose of hope for office-workers and couch potatoes seemed to arrive last week, when a new study suggested that sitting might not be so bad, after all. Based on 16-years of data on more than 5,000 middle-aged adults, UK researchers found no link between prolonged sitting and the risk of death.

But, experts caution, the new findings don’t necessarily contradict or debunk growing evidence for the harms of sedentary lifestyle. One major reason is that participants in the new study were especially active, reporting an average of 15 hours of physical activity per week.

That’s drastically more than the 2.5 weekly hours recommended by many major medical groups. And that suggests that there might be some still-unquantified protective effect of exercise that counteracts the dangers of sitting. The study also looked only at death rates, and not at rates of diseases or other health measures.

Based on the bulk of accumulating data, experts say, a sedentary lifestyle still seems to carry real risks.

“There is a lot of very good research that is ongoing in research groups around the world, which is examining associations between sitting and disease in different populations and most importantly, the underlying biology behind these associations,” says Richard Pulsford, an exercise physiologist at the University of Exeter, and lead author of the new study in the International Journal of Epidemiology.

“When we understand what’s going on under the surface,” he says, “we will know far more about whether sitting or a lack of activity is the most important factor for promoting good health.”

Although scientists have long known that physical activity promotes health, the first clue that sitting could be detrimental for people came in 2009, when researchers looked at data on more than 17,000 Canadians and found that people who sat more were more likely to die from cardiovascular disease.

Since then, a number of large studies in a variety of countries have produced similar results, says Peter Katzmarzyk, an epidemiologist at the Pennington Biomedical Research Institute in Baton Rouge, Louisiana, and co-author of the 2009 study.

Accumulating findings have been both alarming and punctuated by unknowns. In general, studies have shown no “safe level” below which sitting is good and above which sitting becomes bad, Katzmarzyk says. Instead, it appears that progressively more sitting leads to progressively worse consequences. Even avid exercisers suffer more ill effects when they spend more of their non-workout time sitting.

But there is also evidence to suggest that sitters who exercise fare better than sitters who just sit. In a review of 47 studies published in the Annals of Internal Medicine earlier this year, researchers concluded that, among people who did not exercise, prolonged sitting raised risks for various diseases by about 40 percent, says  lead author David Alter, a cardiologist at the University of Toronto. Among avid exercisers, on the other hand, sitting raised risk by just five or 10 percent.

The new UK study supports the idea that the benefits from lots of physical activity can counteract the harms from lots of sitting.

“The real health risks associated with sitting are among those folks who are both sitting for long periods of time and not exercising,” Alter says. “The magnitude of risk really diminishes and is marginal among folks who exercise.”

What science can’t yet offer are clear guidelines on how much exercise is enough in order to justify a long day behind a computer or a relaxing night of binge-watching shows on Netflix. For most people, two hours a day of activity is an unrealistic goal. And while less might still offer protection, the only way to know for sure is with trials that assess the consequences of various amounts and types of movement. That kind of data is not yet available.

Read more at Discovery News

Photo of Iceberg That Sank Titanic on Auction

A photo of the iceberg that likely sank the Titanic — along with a critical testimony about red paint seen on the side of the iceberg — has resurfaced after hanging for nearly a century on a boardroom wall, according to a BBC report.

The photo showing what may be the deadliest iceberg in history, was snapped by the chief steward of the German ocean liner Prinz Adalbert on April 15, 1912 — the morning after the Titanic struck the iceberg and sank, dooming the ship’s 2,200 passengers. While other photos of the iceberg exist, this is the only one that comes with its own testimony.

In the testimony, the steward wrote, “On the day after the sinking of the Titanic, the steamer Prinz Adalbert passes the iceberg shown in this photograph. The Titanic disaster was not yet known by us. On one side red paint was plainly visible, which has the appearance of having been made by the scraping of a vessel on the iceberg.”

The note was signed “M. Linoenewald, and three crewmen.”

The Titanic’s hull was painted red and the red paint on the iceberg most likely had come from the ship as the ice scraped into its side. The Titanic was on its maiden voyage crossing the Atlantic when it hit the iceberg, carrying just over 2,200 passengers and crew. Only 983 people survived the disaster.

The photograph hung for decades on the walls of the law firm representing the Titanic’s owners, White Star Line. The firm closed in 2002, and the four partners of the firm are now putting it up for auction, along with the note.

Read more at Discovery News

400-Year-Old Church Emerges as Reservoir Dries

As Mexico’s parched Nezahualcoyotl reservoir slowly succumbs to drought-like conditions, its receding waters have revealed a haunting relic from the past: a submerged 16th-century church not seen in over a decade.

Originally built by Dominican monks, the church was located in Quechula, a small town that church officials envisioned would eventually become a large population center. Quechula, however, was completely abandoned in the 1770s after a devastating plague ravaged the area.

In the 1960s, what remained of Quechula was completely submerged when Mexican authorities dammed the nearby Grijalva River.

Since then, the church has only been seen in such detail one other time. In 2002, the reservoir was reportedly so low that visitors were able to walk through the church's remains.

So far this year, the reservoir's water level has dropped 75 feet, exposing much of the resilient structure, which stands 48 feet tall at its highest point.

From Discovery News

Attraction Guided by Our Genes

Opposites attract. It’s a basic principle of magnetism that has long been applied to romance. But the problem is that research on relationships shows that this notion, which sounds all well and good in song form, doesn’t ring true in practice.

Instead, we tend to be attracted to people who are similar to us in one way or another. It’s a phenomenon known as assortative mating. Assortative mating can be seen across traits like race, age, facial characteristics and body type, all of which have a genetic basis.

Individuals in fact tend to seek out someone with similar DNA, finds a joint analysis of Latino communities in Mexico, Puerto Rico and the United States by researchers at the University of California – San Francisco, Microsoft Research, Harvard, University of California – Berkeley, and Tel Aviv University.

Couples who pair up in these communities often have similar genetic ancestry, which proves stronger in determining mate selection than other socioeconomic factors, such as education levels, which itself has shown to be a powerful predictor of attraction in previous research.

In fact, ancestry was so similar in the populations studied that the average couple was the genetic equivalent of between third and fourth cousins. This degree of genetic relatedness among mating pairs could have potential health implications, both positively and negatively, as recessive alleles are more commonly passed in partners with similar genetic profiles.

There is a limitation in this study in that the research, appearing the latest Proceedings of the National Academy of Sciences (PNAS), in that it focused on ethnically homogenous communities. Other studies have found similar results, however, when looking at different populations.

Last year, another PNAS study by University of Colorado – Boulder researchers examined the genetic profiles of 825 non-Hispanic white couples. The researchers looked at single-nucleotide polymorphisms, parts of DNA where humans differ from one another. What the scientists found was that married individuals were likely to be more genetically similar than two individuals randomly selected from the same population.

Assortative mating is common, some researchers argue, simply because of population stratification. Individuals tend to coalesce around like individuals, according to ethnic, racial or socioeconomic factors. But there is evidence as well of disassortative mating at a genetic level as well.

A 2009 study presented before the conference of the of the European Society of Human Genetics examined the major histocompatibility complexes (MHCs), a genetic region that plays a key role in immune response and reproductive success, in 90 married couples and compared them with 152 randomly matched pairs set up as control group. Married couples were more likely to choose a mate with diverse MHCs, likely an evolutionary strategy tied to successful reproduction.

Read more at Discovery News

Weird Woodworm-like Pits on Pluto Reveal Icy Puzzle

Like a woodworm-infested log, new photos from NASA’s New Horizons mission of dwarf planet Pluto have revealed a pockmarked terrain that is as puzzling as it is beautiful.

Imaged just before the NASA probe made close approach on July 14, this new view of Pluto’s icy Sputnik Planum region reveals hundreds of pits, a few hundred meters wide by a few tens of meters deep, swarming across the surface. Composed of ices such as nitrogen, planetary scientists are making an early guess that these features are caused by sublimation, but the alignment and location of the pits are a mystery.

Sublimation occurs when an ice turns directly into a vapor without turning into a liquid — like “dry ice” on Earth (carbon dioxide ice), the ice will change phase into a gas without passing through the liquid phase. As there is little atmospheric pressure on Pluto, sublimation is a dominant process; as the abundant surface ices are heated, they vent gases into the tenuous atmosphere, forming a surprisingly complex interplay between the surface and atmosphere.

Indeed, the surprising lack of impact craters on Sputnik Planum shows the surface is constantly being refreshed by new ice likely being layered from the atmosphere and these pits are physical evidence of this bizarrely active ice layer.

“Pluto is weird, in a good way,” said New Horizons project scientist Hal Weaver, of Johns Hopkins Applied Physics Laboratory in Laurel, Md. “The pits, and the way they’re aligned, provide clues about the ice flow and the exchange of volatiles between the surface and atmosphere, and the science team is working hard to understand what physical processes are at play here.”

It’s hard not to imagine what this landscape would look like if we could stand on the surface of Sputnik Planum. We already know that this region is pretty much flat, but the inclusion of these pits would make it look like an ocean of dramatic sinkholes in the ice stretching to the horizon.

Read more at Discovery News

Oct 18, 2015

Novel algorithm simulates water evaporation at the nanoscale

We are all familiar with boiling a pot of water--flame from a stove heats the base of a metal pot, the metal transfers the heat to the water, and the temperature goes up and up until the water boils. Professor Shalabh Maroo and graduate student Sumith YD are looking closer -- much closer. They are looking at heat transfer in water at the nanoscale, where the heat from the pot's atoms transfers to the atoms that make up water.

The evaporation of water that occurs when it meets a hot surface is understood in continuum theory and in experimentation. Before now, researchers were unable to study it at nanoscales in molecular simulation. YD and Maroo's algorithm has made that possible, and their paper, "Surface-Heating Algorithm for Water at Nanoscale," has garnished notable attention in the Journal of Physical Chemistry Letters.

Within their paper, the pair details their development of a new algorithm that simulates the evaporation of water at the molecular scale that matches theoretical, numerical, and real-world observations. In doing so, the team has provided a molecular dynamics tool that allows for the study of various heat transfer problems at the nanoscale, including understanding and utilizing passive liquid flows.

"By capturing realistic differential thermal gradients in water heated at the surface, our algorithm can be an incredibly valuable tool for studying a range of heating and cooling problems. It's also simple enough to be easily integrated into various molecular simulation software and user codes," describes Maroo.

This research is part of Maroo's CAREER award research, in which he is investigating the fundamental physics associated with nanoscale meniscus evaporation and passive liquid flow to remove large amounts of heat from small surfaces in very short amounts of time. This work aims to provide rapid and efficient cooling of next-generation computer chips and energy conversion devices.

From Science Daily

Dates for cataclysms on early moon, Earth questioned

This highly shocked zircon, from the Vredefort Dome in South Africa, shows thin, red bands that are a hallmark of meteorite impact. Uranium-lead dating from this zircon matched the age of the rocks exposed at Vredefort, not the more recent age of impact (2 billion years).
Phenomenally durable crystals called zircons are used to date some of the earliest and most dramatic cataclysms of the solar system. One is the super-duty collision that ejected material from Earth to form the moon roughly 50 million years after Earth formed. Another is the late heavy bombardment, a wave of impacts that may have created hellish surface conditions on the young Earth, about 4 billion years ago.

Both events are widely accepted but unproven, so geoscientists are eager for more details and better dates. Many of those dates come from zircons retrieved from the moon during NASA's Apollo voyages in the 1970s.

A study of zircons from a gigantic meteorite impact in South Africa, now online in the journal Geology, casts doubt on the methods used to date lunar impacts. The critical problem, says lead author Aaron Cavosie, a visiting professor of geoscience and member of the NASA Astrobiology Institute at the University of Wisconsin-Madison, is the fact that lunar zircons are "ex situ," meaning removed from the rock in which they formed, which deprives geoscientists of corroborating evidence of impact.

"While zircon is one of the best isotopic clocks for dating many geological processes," Cavosie says, "our results show that it is very challenging to use ex situ zircon to date a large impact of known age."

Although many of their zircons show evidence of shock, "once separated from host rocks, ex situ shocked zircons lose critical contextual information," Cavosie says.

The "clock" in a zircon occurs as lead isotopes accumulate during radioactive decay of uranium. With precise measurements of isotopes scientists can calculate, based on the half life of uranium, how long lead has been accumulating.

If all lead was driven off during asteroid impact, the clock was reset, and the amount of accumulated lead should record exactly how long ago the impact occurred.

Studies of lunar zircons have followed this procedure to produce dates from 4.3 billion to 3.9 billion years ago for the late heavy bombardment.

To evaluate the assumption of clock-resetting by impact, Cavosie and colleagues gathered zircons near Earth's largest impact, located in South Africa and known to have occurred 2 billion years ago. The Vredefort impact structure is deeply eroded, and approximately 90 kilometers across, says Cavosie, who is also in the Department of Applied Geology at Curtin University in Perth, Australia. "The original size, estimated at 300 kilometers diameter, is modeled to result from an impactor 14 kilometers in diameter," he says.

The researchers searched for features within the zircons that are considered evidence of impact, and concluded that most of the ages reflect when the zircons formed in magma. The zircons from South Africa are "out of place grains that contain definitive evidence of shock deformation from the Vredefort impact," Cavosie says. "However, most of the shocked grains do not record the age of the impact but rather the age of the rocks they formed in, which are about 1 billion years older."

The story is different on Earth, says zircon expert John Valley, a professor of geoscience at UW-Madison. "Most zircons on Earth are found in granite, and they formed in the same process that formed the granite. This has led people to assume that all the zircons were reset by impact, so the ages they get from the Moon are impact ages. Aaron is saying to know that, you have to apply strict criteria, and that's not what people have been doing."

The accuracy of zircon dating affects our view of Earth's early history. The poorly understood late heavy bombardment, for example, likely influenced when life arose, so dating the bombardment topped a priority list of the National Academy of Sciences for lunar studies. Did the giant craters on the moon form during a brief wave or a steady rain of impacts? "It would be nice to know which," Valley says.

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