Seafaring spiders depend on their 'sails' and 'anchors'

Spiders travel across water like ships, using their legs as sails and their silk as an anchor, according to research published in the open access journal BMC Evolutionary Biology. The study helps explain how spiders are able to migrate across vast distances and why they are quick to colonise new areas.

Common spiders are frequently observed to fly using a technique called 'ballooning'. This involves using their silk to catch the wind which then lifts them up into the air. Ballooning spiders are estimated to move up to 30 km per day when wind conditions are suitable, helping in their quest for new habitats and resources.

This dispersal strategy, however, involves a significant risk. The airborne spider has little control over where it travels and could end up landing on water, which has been thought to be unsuitable for its survival.

Lead author Morito Hayashi from the Natural History Museum, London, UK, said: "Even Darwin took note of flying spiders that kept dropping on the Beagle miles away from the sea shore. But given that spiders are terrestrial, and that they do not have control over where they will travel when ballooning, how could evolution allow such risky behavior to be maintained?"

"We've now found that spiders actively adopt postures that allow them to use the wind direction to control their journey on water. They even drop silk and stop on the water surface when they want. This ability compensates for the risks of landing on water after the uncontrolled spider flights."

The researchers collected 325 adult spiders belonging to 21 common species from small islands in nature reserves in Nottinghamshire, UK. The spiders' behavior was observed on trays of water in reaction to pump-generated air, and this was compared to their reactions on dry surfaces.

Many of the spider species adopted elaborate postures, such as lifting up a pair of legs, to seemingly take advantage of the wind current whilst on the water surface. This allowed them to 'sail' in turbulent, still, fresh, and salt water conditions.

By releasing silk on water, the sailing spiders also seemed to act like ships dropping their anchors to slow down or stop their movement. This suggests that the silk may sometimes work as a dragline for the water-trapped spider to attach to floating objects or to the shore. These behavioral adaptations could allow spiders to survive encounters with aquatic environments.

The research team also found that the spiders that adopted 'ballooning' behavior for airborne dispersal were also the most eager and able 'sailors'. The association between the two behaviors may indicate the importance of ballooners also being able to sail, which could be invaluable when landing on water.

Read more at Science Daily

Ridges and valleys: Experiments open window on landscape formation

University of Oregon geologists have seen ridges and valleys form in real time and -- even though the work was a fast-forwarded operation done in a laboratory setting -- they now have an idea of how climate change may impact landscapes.

On a basic-science front, the findings, which appear in the July 3 issue of the journal Science, provide a long-sought answer to why some landscape features appear so orderly, with distinct and evenly spaced valleys and ridges.

Picture the Painted Hills near John Day, Oregon, the Colorado Plateau, the badlands of Montana and South Dakota, and even portions of the Coastal Range between Eugene and Florence, Oregon. These watersheds are masterpieces that nature has formed over geological timescales, said the UO's Joshua J. Roering.

The regularity of hill and valley landforms, he said, is reached after a long tug-of-war between erosion driven by runoff, which influences how rivers cut their paths in valley floors, and soil movement on hillsides caused by disturbances from such things as burrowing gophers, tree roots, digging ants and frost.

The National Science Foundation-funded project (EAR 1252177) is part of a growing effort in geomorphology -- the study of the origin and evolution of many landscape features -- to understand how soil processes at work on hillsides compete with water runoff in the formation of valley floors.

Put simply, runoff processes carve valleys while soil movement on hill slopes tends to fill them. The relative vigor of these competing forces determines the spacing of hills and valleys and the degree of drainage dissection. "Hill-slope processes help determine valley density and the way valleys and ridges form," Roering said. "These networks are climate dependent."

Over the course of five 20-hour experiments conducted in small sandboxes, UO doctoral student Kristin E. Sweeney, the study's lead author, extruded crystalline silica to represent uplift due to tectonic forces. To induce erosion, she used mist from 42 nozzles to create precipitation-driven runoff and 625 blunt needles that fired periodic bursts of large water drops to mimic natural disturbances that occur on hill slopes. Each experiment showed how the processes, acting together, converted flat plains into ridges and valleys.

"In our experiments we were able to dictate the processes involved and observe the landscapes that arise," Sweeney said. "We were able to directly control the various processes. Previous research has only attempted to replicate channel processes -- what the rivers do. We essentially started from scratch, working to see the movement of sediment slopes in a realistic way.

"Ridges and valleys are part of a fundamental landscape pattern that people easily recognize," she said. "From an airplane, you look down and you see watersheds, you see valleys, and they tend to have very regular spacing. Explaining this pattern is a fundamental question in geomorphology."

The study's three-member team also included Christopher Ellis, senior research associate at the University of Minnesota's St. Anthony Falls Laboratory where the experiments were conducted. The team spent more than a year developing a workable methodology to study the sediment transfer processes.

Read more at Science Daily

Why the seahorse's tail is square

Why is the seahorse's tail square? An international team of researchers has found the answer and it could lead to building better robots and medical devices. In a nutshell, a tail made of square, overlapping segments makes for better armor than a cylindrical tail. It's also better at gripping and grasping. Researchers describe their findings in the July 3 issue of Science.

"Almost all animal tails have circular or oval cross-sections--but not the seahorse's. We wondered why," said Michael Porter, an assistant professor in mechanical engineering at Clemson University and the lead investigator on the study, who earned his Ph.D. in materials science and engineering at the University of California, San Diego, in 2014. "We found that the squared-shaped tails are better when both grasping and armor are needed."

Also remarkable, the square plates make the seahorse's tail stiffer, stronger and more resistant to strain at the same time. Usually, strengthening any one of these characteristics will weaken at least one of the others, Porter said. He and colleagues set out to find out why.

They found that square plates move with only one degree of freedom when crushed: they slide. By contrast, circular plates have two degrees of freedom: they slide and they rotate. As a result, the square plates absorb much more energy before permanent failure begins.

To arrive at their findings, researchers used a wide range of techniques, including 3D-printing a simplified model of the seahorse's tail, which they then bent, twisted, compressed and crushed. They also 3D-printed and ran similar experiments on a tail model made of overlapping round segments that they designed and that is not found in nature.

"New technologies, like 3D-printing, allow us to mimic biological designs, but also build hypothetical models of designs not found in nature," said Porter "We can then test them against each other to find inspiration for new engineering applications and also explain why biological systems may have evolved."

The Science study builds on work Porter started at UC San Diego in collaboration with Dominique Adriaens, professor of evolutionary biology at Ghent University and UC San Diego materials science and engineering professors Joanna McKittrick and Marc Meyers. "Michael decided to use engineering and technology to explain biological features," said McKittrick, who was Porter's co-advisor and is a co-author on the paper. You can simplify nature and study it in the lab, added Meyers, also a co-author and Porter co-advisor. "Then you can build new bioinspired structures and devices."

Porter's research group at Clemson is now applying this method to develop new structures and robotic systems that mimic a variety of other natural--and hypothetical--systems, allowing him to translate his research across disciplines: from biology as a source of inspiration for engineering; and from engineering as a tool for the exploration of biology.

Grasping, gripping

When researchers twisted the 3D-printed square seahorse tail model, they found that its plates interfered with one another, limiting its range of movement by about half when compared to the model made of round segments. In addition, after it was twisted, the square model returned to its original shape faster, while expending a minimum amount of energy. Researchers theorize this might protect the tail from damage. By contrast, a tail made from round segments twists easily and requires more energy to return to its original shape. Researchers also found that the tail's square segments created more contact points with the surface that it is gripping when compared to a tail with round segments.

In addition, a seahorse's tail bends in a way that allows it to grasp objects within its line of sight. Study co-author Ross L. Hatton, assistant professor of mechanical engineering at Oregon State University and specialist in robotics, helped Porter develop geometric models describing the tail's mechanics and proving its geometry is optimized precisely for this kind of grasping.

Armor

Researchers also compressed the models made of 3D-printed segments and compared their behavior to 3D-printed solid structures with square and circular cross-sections--but without segments. They found that a seahorse's tail has joints at the exact locations where the solid structures fail when crushed. This allows the structures to absorb more energy on impact. Even more impressive, the square model outperformed the round one in all crushing tests. This is because square segments fail without changing their general shape. By contrast, round segments open up under the applied load, changing their shape from circular to elliptical.

This is important, because water birds are one of the seahorse's main predators and capture their prey with their beaks and crush them in the process.

Applications

Porter is also investigating how devices inspired by the structure of the seahorse's tail could be used in real life. One possibility is to scale up the structure to build a gripping robotic arm that can be used in hostile environments. Another is to scale it down to build a catheter. But the possibilities are many, said study co-author Meyers.

Read more at Science Daily

Old World monkey had tiny, complex brain

The brain hidden inside the oldest known Old World monkey skull has been visualized for the first time. The ancient monkey, known as Victoriapithecus, first made headlines in 1997 when its 15 million-year-old skull was discovered on an island in Kenya's Lake Victoria. Now, thanks to high-resolution X-ray imaging, researchers have peered inside its cranial cavity and created a three-dimensional computer model of what the animal's brain likely looked like. Its tiny but remarkably wrinkled brain supports the idea that brain complexity can evolve before brain size in the primate family tree. The creature's fossilized skull is now part of the permanent collection of the National Museums of Kenya in Nairobi.

The brain hidden inside the oldest known Old World monkey skull has been visualized for the first time. The creature's tiny but remarkably wrinkled brain supports the idea that brain complexity can evolve before brain size in the primate family tree.

The ancient monkey, known scientifically as Victoriapithecus, first made headlines in 1997 when its fossilized skull was discovered on an island in Kenya's Lake Victoria, where it lived 15 million years ago.

Now, thanks to high-resolution X-ray imaging, researchers have peered inside its cranial cavity and created a three-dimensional computer model of what the animal's brain likely looked like.

Micro-CT scans of the creature's skull show that Victoriapithecus had a tiny brain relative to its body.

Co-authors Fred Spoor of the Max Planck Institute for Evolutionary Anthropology and Lauren Gonzales of Duke University calculated its brain volume to be about 36 cubic centimeters, which is less than half the volume of monkeys of the same body size living today.

If similar-sized monkeys have brains the size of oranges, the brain of this particular male was more akin to a plum.

"When Lauren finished analyzing the scans she called me and said, 'You won't believe what the brain looks like,'" said co-author Brenda Benefit of New Mexico State University, who first discovered the skull with NMSU co-author Monte McCrossin.

Despite its puny proportions, the animal's brain was surprisingly complex.

The CT scans revealed numerous distinctive wrinkles and folds, and the olfactory bulb -- the part of the brain used to perceive and analyze smells -- was three times larger than expected.

"It probably had a better sense of smell than many monkeys and apes living today," Gonzales said. "In living higher primates you find the opposite: the brain is very big, and the olfactory bulb is very small, presumably because as their vision got better their sense of smell got worse."

"But instead of a tradeoff between smell and sight, Victoriapithecus might have retained both capabilities," Gonzales said.

The findings, published in the July 3 issue of Nature Communications, are important because they offer new clues to how primate brains changed over time, and during a period from which there are very few fossils.

"This is the oldest skull researchers have found for Old World monkeys, so it's one of the only clues we have to their early brain evolution," Benefit said.

In the absence of fossil evidence, previous researchers have disagreed over whether primate brains got bigger first, and then more folded and complex, or vice versa.

"In the part of the primate family tree that includes apes and humans, the thinking is that brains got bigger and then they get more folded and complex," Gonzales said. "But this study is some of the hardest proof that in monkeys, the order of events was reversed -- complexity came first and bigger brains came later."

Read more at Science Daily

'Map Of Life' predicts ET. (So where is he?)

Extra-terrestrials that resemble humans should have evolved on other, Earth-like planets, making it increasingly paradoxical that we still appear to be alone in the universe, the author of a new study on convergent evolution has claimed.

The argument is one of several that emerge from The Runes Of Evolution, a new book in which the leading evolutionary biologist, Professor Simon Conway Morris, makes the case for a ubiquitous "map of life" that governs the way in which all living things develop.

It builds on the established principle of convergent evolution, a widely-supported theory -- although one still disputed by some biologists -- that different species will independently evolve similar features.

Conway Morris argues that convergence is not just common, but everywhere, and that it has governed every aspect of life's development on Earth. Proteins, eyes, limbs, intelligence, tool-making -- even our capacity to experience orgasms -- are, he argues, inevitable once life emerges.

The book claims that evolution is therefore far from random, but a predictable process that operates according to a fairly rigid set of rules.

If that is the case, then it follows that life similar to that on Earth would also develop in the right conditions on other, equivalent planets. Given the growing number of Earth-like planets of which astronomers are now aware, it is increasingly extraordinary that aliens that look and behave something like us have not been found, he suggests.

"Convergence is one of the best arguments for Darwinian adaptation, but its sheer ubiquity has not been appreciated," Professor Conway Morris, who is a Fellow at St John's College, University of Cambridge, said.

"Often, research into convergence is accompanied by exclamations of surprise, describing it as uncanny, remarkable and astonishing. In fact it is everywhere, and that is a remarkable indication that evolution is far from a random process. And if the outcomes of evolution are at least broadly predictable, then what applies on Earth will apply across the Milky Way, and beyond."

Professor Conway Morris has previously raised the prospect that alien life, if out there, would resemble earthlings -- with limbs, heads, and bodies -- notably at a Royal Society Conference in London in 2010. His new book goes even further, however, adding that any Earth-like planet should also evolve thunniform predators (like sharks), pitcher plants, mangroves, and mushrooms, among many other things.

Limbs, brains and intelligence would, similarly, be "almost guaranteed." The traits of human-like intelligence have evolved in other species -- the octopus and some birds, for example, both exhibit social playfulness -- and this, the book suggests, indicates that intelligence is an inevitable consequence of evolution that would characterise extraterrestrials as well.

Underpinning this is Conway Morris' claim that convergence is demonstrable at every major stepping stone in evolutionary history, from early cells, through to the emergence of tissues, sensory systems, limbs, and the ability to make and use tools.

The theory, in essence, is that different species will evolve similar solutions to problems via different paths. A commonly-cited example is the octopus, which has evolved a camera eye that is closely similar to that of humans, although distinctive in important ways that reflect its own history. Although octopi and humans have a common ancestor, possibly a slug-like creature, this lived 550 million years ago and lacked numerous complex features that the two now share. The camera eye of each must therefore have evolved independently.

Conway Morris argues that this process provides an underlying evolutionary framework that defines all life, and leads to innumerable surprises in the natural world. The book cites examples such as collagen, the protein found in connective tissue, which has emerged independently in both fungi and bacteria; or the fact that fruit flies seem to get drunk in the same manner as humans. So too the capacity for disgust in humans -- a hard-wired instinct helping us avoid infection and disease -- is also exhibited by leaf-cutter ants.

The study also identifies many less obvious evolutionary "analogues," where species have evolved certain properties and characteristics that do not appear to be alike, but are actually very similar. For example, "woodpeckerlike habits" are seen in lemurs and extinct marsupials, while the mechanics of an octopus' tentacles are far closer to those of a human arm than we might expect, and even their suckers can operate rather like hands.

Conway Morris contends that all life navigates across this evolutionary map, the basis of what he describes as a "predictive biology." "Biology travels through history," he writes, "but ends up at much the same destination."

This, however, raises fascinating and problematic questions about the possibility of life occurring on other planets. "The number of Earth-like planets seems to be far greater than was thought possible even a few years ago," Conway Morris said. "That doesn't necessarily mean that they have life, because we don't necessarily understand how life originates. The consensus offered by convergence, however, is that life is going to evolve wherever it can."

"I would argue that in any habitable zone that doesn't boil or freeze, intelligent life is going to emerge, because intelligence is convergent. One can say with reasonable confidence that the likelihood of something analogous to a human evolving is really pretty high. And given the number of potential planets that we now have good reason to think exist, even if the dice only come up the right way every one in 100 throws, that still leads to a very large number of intelligences scattered around, that are likely to be similar to us."

If this is so, as the book suggests in its introduction, then it makes Enrico Fermi's famous paradox -- why, if aliens exist, we have not yet been contacted -- even more perplexing. "The almost-certainty of ET being out there means that something does not add up, and badly," Conway Morris said. "We should not be alone, but we are."

Read more at Science Daily

If This Wasp Stings You, ‘Just Lie Down and Start Screaming’

This is the business end of the tarantula wasp, and by business end I mean the end that once made a guy crawl into a ditch and cry. True story.

Justin Schmidt is an entomologist, and has accordingly been stung by a lot of bugs. So he invented something called the Schmidt sting pain index (named after some guy called Schmidt, apparently), which ranks the pain of insect stings from one to four. Down at one is something like the fire ant, which is so named for a reason, while up at four is the bullet ant, which is so called for a very, very good reason.

Joining the bullet ant at four is a critter that lives right here in the southwestern US: the tarantula hawk. It’s actually a kind of solitary wasp with a sting whose resulting pain only lasts three seconds, but it’s so fiercely electric that could only be described as totally unacceptable. “There are some vivid descriptions of people getting stung by these things,” says invertebrate biologist Ben Hutchins of Texas Parks and Wildlife, “and their recommendation—and this was actually in a peer-reviewed journal—was to just lie down and start screaming, because few if any people could maintain verbal and physical coordination after getting stung by one of these things. You’re likely to just run off and hurt yourself. So just lie down and start yelling.”

Either this wasp is giant or this is a child holding it. Probably the former though, on account of child endangerment.

That paper, as it happens, was written by our friend Schmidt, and is probably the most unintentionally hilarious scientific paper I’ve ever read. He recounts one enterprising scientist who netted 10 tarantula hawks—and of course reached in to grab them: “Undeterred after the first sting, he continued, receiving several more stings, until the pain was so great he lost all of them and crawled into a ditch and just bawled his eyes out.”

Which is why folks in Texas have seemed a bit…worried over the past few weeks, as numbers of the things are on the rise. In reality, though, there’s nothing to be worried about here (trust me). The tarantula hawk is in fact a brilliant parasite that attacks tarantulas, not humans, paralyzing them with a sting before dragging them into a den. Here it lays an egg that hatches into a larva and devours the paralyzed spider alive—over the course of several weeks.

A tarantula wasp faces off against its namesake victim: the hawk.

So take heart, dear Texans. You’d have to try real hard to get stung by these things, like picking them up or stepping on them. Quite frankly, they don’t seem to pay people no mind, even if approached, probably because they know they could kick human asses all over the place. “The tarantula hawks are really bold in terms of wasps,” says Hutchins. “Researchers think that’s because they have very few natural predators. They have such an effective deterrent mechanism, and that’s their really painful sting.” Indeed, there are almost no reports of any animal dumb enough going after these things.

Accordingly, there’s not much to stop them when their numbers start climbing, like they are right now in Texas. Thanks to a strong rainy season, vegetation is doing quite well, and when vegetation does quite well, so do insects. The tarantula hawk is actually a nectar-feeder, not a carnivore, so it’s in fat city these days.

But not all of these wasps sting: The males can’t do it at all. This is because stingers in the insect world belong to the females (the structures evolved from ovipositors, which the females use to lay eggs). So in lovely conditions such as these, males will hang out on flowers and wait for the females to come around and mate. The female then flies off—and this is where the real fun begins.

Except for the tarantulas. They’re not going to like this one bit.

Sting Operation

Unlike a lot of insects, the fertilized female won’t just be depositing her eggs somewhere and flying off, hoping they’ll survive on their own. Nope, she finds an unwitting caretaker first: specifically, any number of tarantulas that are also good and active during these times of plenty.

The she-wasp has to be careful, because while she’s pretty darn big, the tarantula can be several times bigger than her. And although tarantulas may be harmless to humans, they have massive fangs that could do a number on the wasp. “The tarantula hawk will kind of approach the tarantula,” says Hutchins, “back away, approach, and then go in and actually get in underneath the tarantula and then flip it over, and then sting it. She’s usually looking for a chink in the tarantula’s armor, and that’s often at the joints in the legs.”

And she’s really good at it. One survey found that in 400 battles, only a single wasp perished. But that isn’t to say the tarantulas weren’t putting up a good fight. In his sneakily comic scientific paper, Schmidt notes that researchers have reported “violent encounters, often hearing loud crunching or snapping sounds as the spider has the wasp in its jaws, and with spiders frequently losing legs during the encounters.” It seems that the tarantula hawks’ hard, smooth exoskeletons may crunch a bit, but they still save their owners from death.

The wasp drags its victim to its doom. Not the wasp’s doom. The spider’s. Boy I’m on a roll this week.

As for the tarantulas, well, they almost never escape. The sting paralyzes the spider nearly instantly, allowing the wasp to drag it into a pre-dug burrow or back to the tarantula’s own den. Here it drops the victim and lays a single egg on it, then leaves and seals the chamber behind it. The egg hatches into a larva, which starts eating the still-paralyzed spider, focusing on non-essential tissues to keep it alive for as long as possible—perhaps weeks.

That there is one hell of a head start in life for the kiddo. It’s a striking contrast to the lives of social wasps, which collectively care for their young without encouraging them to devour paralyzed tarantulas. And indeed, this manifests in the wasps’ venom itself. Typically, the venom of social wasps tends to be both painful and damaging to tissue, whereas the tarantula hawk’s is all agony and no damage. This is likely because social wasps have a queen and young to protect from their enemies, so simply inflicting pain may not do the trick—the target may be down, but not out. In contrast, the tarantula hawk is a lone wolf, looking out only for itself. All it has to do is stun its attacker and make a getaway.

Read more at Wired Science

Roman Villa Reopens on Wild Tuscan Island

The remains of one of the most prestigious maritime villas from Roman times are set to reopen July 2 in a small, almost uninhabited island off the Tuscan coast after been locked for 15 years.

Commonly known as “Villa Domitia,” the imperial complex stood magnificently 2,000 years ago on the island of Giannutri, a rocky crescent about 3 miles long with thick areas of Mediterranean vegetation.

"The villa was built on a harsh, uninhabited site, "Paola Rendini, of the archaeological superintendency of Tuscany, told Discovery News. "There is no water spring on the island, and raw materials had to be carried from the mainland. It was a huge task,"

Despite such difficulties, the Romans managed to shape up a sprawling "otium" (leisure) villa, lavishly decorated with precious marbles, mosaics and frescoes.

The majestic complex marks Giannutri’s most glorious time. Today the southernmost island of the Tuscan archipelago is almost empty -- populated by a huge colony of seagulls and, in summer, by a group of villa owners who rely on rain water and water shipped from the mainland.

The island has a complex recent history, marked by legal and administrative issues. A number of authorities coexist on this piece of land which is fewer than 4 square miles in size.

Part of the Tuscan Archipelago National Park, the island belongs to the municipality of Giglio island and is largely privately owned, apart from some areas owned by Italy’s Ministry of the Environment. The Villa Domitia and its annexes are under the control of Italy’s Ministry of Cultural Heritage.

Although the villa has been the focus of several restoration and conservation campaigns since 1989, overlapping regulations have basically prevented its opening to the public, slowing procedures and interventions.

"Finally, this jewel can be seen. We are very proud of this reopening," Sergio Ortelli, the mayor of Giglio and Giannutri islands, told Discovery News.

A year after the removal of the Costa Concordia shipwreck, Giglio is struggling to restore its well deserved reputation of unspoiled island rich in food, wine, traditions and history.

"The opening in Giannutri goes in this direction. In hard times, focusing on culture always pays off," Ortelli said.

Today the ruins represent a bright yet fragmented evidence of the once sumptuous villa, showing impressive flights of steps, granite columns, intricately-sculpted capitals, pieces of precious marbles and long stretches of thick walls in opus reticulatum (small squared stones laid diagonally to form a net-like pattern).

Spreading for about 10 acres, the villa was built on different terraces on a property which most likely belonged to the prominent Domitii Ahenobarbi, Nero’s family.

Brick stamps recovered at the site attest to three major building phases: the first dates to the end of the first century A.D., in the late Flavian period (A.D. 69–96), another to the early second century A.D. and the third to the reign of Hadrian.

"Giannutri was the first island after Ostia, the port of Rome, thus relatively easy to reach. The villa was likely used by the emperors Domitian, Trajan and Hadrian," Rendini said.

Rendini, who has been working on the site since 1981, noted Villa Domitia represents one of the most intelligible evidences of a leisure imperial residence, fully equipped with all comforts.

Relying on large cisterns, a sophisticated system collected rainwater and solved the problem of the lack of springs on the island. Indeed, those cisterns are still in use today to provide water on Giannutri.

An underfloor heating system allowed a pleasant winter stay at the villa, which was also equipped with thermal baths.

The complex had two well protected harbors, one on Cala Spalmatoio on the eastern coast, and the other at Cala Maestra, on the western side. Near this harbor, remains of a structure for the production of salted fish have been found.

The residential quarter, which included the bedrooms and a large room with stunning views over the sea, spread on three terraces around an open courtyard. This featured a rectangular basin for collecting rainwater, surrounded by six imposing granite columns boasting intricately carved Corinthian capitals.

On a much higher level, toward east, are the remains of the slave quarters.

Only partially excavated, the villa was first brought to light in the 1920-1930 by Bice Vaccarino, a woman who had rented the island, in collaboration with archaeologist Doro Levi.

"In 1928 a great marble flight of steps that goes down to the sea first emerged, revealing the importance and the (wealth) of the villa," the journal Emporium wrote in 1931.

Reporting on Vaccarino's archaeological efforts, the account described newly unearthed rooms with polychrome marbles and geometrical patterns and impressive mosaics such as one showing a marine scene with two dolphins.

Read more at Discovery News

Climate Change Can Cause Animals to Switch Sex

Climate has such a powerful effect on animals that it can cause some males to develop as females, according to a new study on wild populations of Australian central bearded dragons.

The discovery, reported in the latest issue of the journal Nature, documents the first known case of sex reversal in the wild for a reptile.

“Sex reversal occurs when the genetic sex of an individual, usually represented by sex chromosomes, is reversed to the other sex,” senior author Arthur Georges explained to Discovery News. “An example would be in humans, where an XY individual, normally a boy, develops as a girl because of some mutation that renders the key male determining gene on the Y chromosome inoperable.”

Georges is a professor and chief scientist at the University of Canberra’s Institute for Applied Ecology. He and his colleagues combined field data from 131 wild-caught adult lizards with controlled breeding experiments.

Among the caught lizards, the researchers identified 11 sex-reversed individuals. For this species, the lizards have a ZZ/ZW system of chromosomal sex determination. A ZZ is male and a ZW is female. The system is similar to that of birds.

For the 11 sex-reversed animals, however, individuals had male ZZ chromosomes yet were anatomically female. What’s more, they could reproduce and often became supermoms within their population. As Georges said, “dads make better mums,” at least in this case.

“We showed that sex-reversed individuals, ZZ females, are larger more robust individuals and lay twice as many eggs as normal ZW females,” he added. “Dads reversed to become mums make better mums than ordinary mums.”

The 11 sex-reversed lizards were caught near the border of the Australian central bearded dragon’s range, close to the border of Queensland and New South Wales. This is a semi-arid region that tends to get hotter than the rest of the lizard’s range.

When the sex-reversed females were mated with normal males, none of the offspring had sex chromosomes, and their sex was entirely determined by egg incubation temperature. Previously it was thought that chromosomes solely determined the sex of a lizard in the wild. Now it is known that the temperature of egg incubation can affect a wild-born individual’s sex as well.

When the offspring themselves later mated with others, their young were more likely to be sex reversed, presumably because of an inherited propensity.

Sex reversals have been reported in other animals too. The phenomenon is common among fish, happening because of aging, environmental temperature, and other factors. It has also been reported in amphibians, but only in a lab setting so far.

In terms of people, Georges said, “Sex reversal occurs occasionally in humans, and presumably in other mammals, but usually comes to attention because the individuals present with clinical symptoms.”

“In some cases, though, it can come as a complete shock to a man to discover that he has XX chromosomes, or for a woman to discover that she has XY chromosomes,” he added.

There is little chance, though, for climate to influence sex determination in humans. Georges said that “the developing embryo is buffered from temperature variation,” given that it is within its mother’s body.

Read more at Discovery News

Why Do Fugitives Flee to Mexico?

After breaking out of Clinton Correctional Facility in New York more than three weeks ago, fugitives David Sweat and Richard Matt intended to spend the rest of their days as free men in Mexico.

Their scheme, which involved murdering the husband of an accomplice and taking his car south of the border, fell apart as a result of weak planning and a strong police response. Matt died in a shootout with police, and Sweat is currently recovering from injuries in a state hospital before he is sent back to prison.

Criminal actions of these men aside, no doubt their prison break showed a high level of ingenuity. So why was their plan for after their escape, hiding away in Mexico, so cliché?

One possible explanation is the common mistaken belief that the United States and Mexico do not have an extradition treaty. Under that assumption, any American felon who manages to step across the border would not have to worry about setting foot in prison ever again.

In truth, the United States and Mexico do have a bilateral extradition treaty, first signed in 1978. Since the early 2000s, the number of fugitives that Mexico has sent back to U.S. authorities has increased at a steady pace. Between 2003 and 2011, more than 2,000 criminals were captured and returned to the United States for prosecution, according to U.S. Marshals data.

Once criminals cross the border successfully, they may think themselves in the clear, but the federal government has means of tracking them to determine where they’ve been and where they might be going. Cameras, face-detection technology and license plate readers along the border can identify fugitives and their vehicles. Most non-Mexican criminals tend to stay close to the border after all, as they’re more likely to stand out as they travel deeper into Mexican territory.

Criminals also may sabotage their own efforts at escape by using technology, particularly when their devices give away their whereabouts. In 2013 for example, Wanda Lee Ann Podgurski, convicted of disability and insurance fraud earlier that year, was apprehended in Mexico after tweeting “Catch me if you can.” Although U.S. Marshals declined to disclose how exactly they tracked down Podgurski, the district attorney involved in the case hinted that the tweet played a role. The most likely explanation is that authorities used the tweet to access her IP address, allowing law enforcement to pinpoint her real-world location.

U.S. and Mexican authorities also engage in cross-border cooperation on law enforcement matters. The U.S. Marshals Service, which has a task force dedicated to finding and capturing criminals on the lam, leads efforts on this side of the border to capture felons fleeing south. They even have a field office in Mexico to assist in coordination with Mexican authorities.

Even if a criminal manages to elude authorities for a week, a month, a year or more, U.S. law enforcement continues to pursue fugitives even when the trail has gone cold. Earlier this year, FBI agents, who were in Guadalajara seeking information on another fugitive, received a tip on Robert Woodring, who had been on the lam in Mexico for 37 years. Even though Woodring managed to avoid capture for nearly five times longer than his original sentence, his arrest must certainly cause discomfort for any fugitive in Mexico who thought him/herself home free.

As with fugitives who remain in the United States, not every one that crosses the border will get picked up by police of course. In 2010, federal estimates suggested about 1,000 fugitives wanted for crimes in the United States were believed to be hiding out in Mexico.

Even criminals who are caught won’t necessarily face justice in the United States. Mexico, like many European countries and Canada, will not extradite a felon unless the government has a guarantee that individual will not face the death penalty upon return to the United States. Mexico will extradite if the maximum penalty is a life sentence, however. U.S. prosecutors are loath to make such concessions, but as one attorney told USA Today in 2008, “The option we have is absolutely no justice, or partial justice.”

Read more at Discovery News

New Photos Show a Two-Faced Pluto

As we anticipate the July 14 Pluto flyby — as NASA’s New Horizons spacecraft zips through the dwarf planet’s system of moons — in new images published by the mission team on Wednesday, the small world has revealed it has two faces.

Beginning to look like a fuzzy, slightly paler version of Mars, Pluto seems to have a huge diversity of surface features, even from a distance of over 9.5 million miles (15 million kilometers) and it’s beginning to look like the dwarf planet has two very distinct hemispheres. One “face” is smooth, with large dark features; the opposite side appears to have a peculiar series of spots spanning Pluto’s equator, all roughly the same size, around 300 miles (480 kilometers) in diameter.

“It’s a real puzzle — we don’t know what the spots are, and we can’t wait to find out,” said Alan Stern, New Horizons’ principal investigator at the Southwest Research Institute, in Boulder, Colo. “Also puzzling is the longstanding and dramatic difference in the colors and appearance of Pluto compared to its darker and grayer moon Charon.”

Indeed, the difference in color is becoming more pronounced on every image release. Pluto has a ruddy yellow hue, whereas Charon’s color appears to have more in common with our moon than Pluto. It is worth noting, however, that these images are still very early in the flyby game, so we’ll need to be patient until we start drawing any conclusions about surface composition or whether Pluto possesses clouds in its thin exosphere.

In other news from the Kuiper Belt, the New Horizons infrared spectrometer is online and has detected frozen methane on Pluto’s surface. Astronomers have known about the spectroscopic signature of methane on Pluto since 1976, but the mission will study the distribution of this molecule around the dwarf planet to see how it varies.

Read more at Discovery News

Gigantic Sinkholes Dot Surface of Rosetta's Comet

Scientists have found gigantic sinkholes more than 200 yards (183 meters) in diameter -- twice the length of a football field -- and just about as deep breaking the surface of the comet being studied by the orbiting Rosetta spacecraft.

“The really cool thing about these sinkholes is that you can stare right into that comet. It’s just crazy. You can see a lot of features in the walls,” University of Maryland planetary scientist Dennis Bodewits told Discovery News.

The pits have near-circular openings, cylindrical shapes and steep walls. At least one of the 18 holes seems to be on a steep angle. Some are active, spewing out jets of dust from their walls or floors.

“Finding the pits was a total surprise,” said space physicist Paul Weissman, with NASA’s Jet Propulsion Laboratory in California.

Scientists suspect the pits are sinkholes that formed when material near the comet’s surface collapsed. The comet’s nucleus is only about half as dense as solid water ice, with an interior that is believed to be mostly empty space.

The comet, known as 67P/Churyumov-Gerasimenko, is is thought to be a "rubble pile" of boulder-sized chunks of silicates and organics that came together to form the comet’s body.

Once the pits form, newly exposed material escapes to space, causing the walls to slowly widen, scientists theorize.

“A fresh cometary surface will have a ragged structure with many pits, while an evolved surface will look smoother,” Jean-Baptiste Vincent, with Germany’s Max Planck Institute for Solar System Research, and colleagues write in this week’s Nature.

“I think they are sinkholes, but I don’t know that for certain,” Weissman, who was not involved in the research, told Discovery News.

“The mass we’ve seen in outbursts from this comet so far is not enough to empty one of these sinkholes,” he said. “Also, also if you look at the surface around the pits, there’s no evidence of debris having been thrown out and then falling back on to the comet. So that leaves us sinkholes. I don’t know that anyone has come up with any other explanation of how they may have formed. I think it’s a good explanation, but we don’t know for certain.”

Similar circular features were found on comets Wild-2 (pronounced “Vilt 2”) and Tempel-1, which were visited by NASA’s Stardust and Deep Impact space probes, respectively. Those depressions, however, were not nearly as deep as the cavities found on 67P, which Europe’s Rosetta spacecraft has been circling since August 2014.

“That suggested that these were older surfaces, older features that had been eroded and filled in,” Bodewits said.

Based in the size and location of 67P’s pits, scientists suspect some variation in materials or structure a few hundred yards beneath the surface.

Read more at Discovery News

'Jesus Lizard' First Walked on Water in Wyoming

Seventeen million years after dinosaurs became extinct, the world’s first known Jesus lizard walked on water in Wyoming, according to a new study.

The agile reptile, described in the journal PLOS ONE, provides clues on how Jesus lizards evolved, and what their early habitats were like. Such lizards are still alive today, with the group (Corytophanidae) including such well-known members as iguanas and chameleons.

The new fossil species, unearthed appropriately in what’s known as the Lucky Lizard Locality of Uinta County, Wyo., has been named Babibasiliscus alxi. Author Jack Conrad of the American Museum of Natural History explained that “Babi” is a Shoshone Native American word meaning “older male cousin.”

“The generic name is meant to honor the Shoshone people who originally inhabited the areas in which the specimen was discovered,” he wrote, adding that the inclusion of the term for “cousin” refers to the relationship of the animal with other Jesus lizards.

Conrad said that Wyoming at the time had a climate matching today’s tropics. The newly discovered lizard used to skim the surfaces of lush, watery habitats there.

The lizard’s fossils suggest that, when alive, it was around 2 feet long. Conrad believes the Jesus lizard was active during the day and spent a lot of time in trees.

A ridge of bone on the skull gave the lizard an angry look while providing shade for its eyes. The look must have terrified prey, which for this predatory lizard was ample. Conrad noted that each of its small teeth had three points suitable for eating snakes, lizards, fish, insects and plants.

The lizard also had large cheekbones, which suggest it could enjoy larger prey items as well.

Read more at Discovery News

South Africans used milk-based paint 49,000 years ago

An international research team led by the University of Colorado Boulder and the University of Witwatersrand in Johannesburg, South Africa has discovered a milk-and ochre-based paint dating to 49,000 years ago that inhabitants may have used to adorn themselves with or to decorate stone or wooden slabs.

While the use of ochre by early humans dates to at least 250,000 years ago in Europe and Africa, this is the first time a paint containing ochre and milk has ever been found in association with early humans in South Africa, said Paola Villa, a curator at the University of Colorado Museum of Natural History and lead study author. The milk likely was obtained by killing lactating members of the bovid family such as buffalo, eland, kudu and impala, she said.

"Although the use of the paint still remains uncertain, this surprising find establishes the use of milk with ochre well before the introduction of domestic cattle in South Africa," said Villa. "Obtaining milk from a lactating wild bovid also suggests that the people may have attributed a special significance and value to that product."

The powdered paint mixture was found on the edge of a small stone flake in a layer of Sibudu Cave, a rock shelter in northern KwaZulu-Natal, Africa, that was occupied by anatomically modern humans in the Middle Stone Age from roughly 77,000 years ago to about 38,000 years ago, said Villa. While ochre powder production and its use are documented in a number of Middle Stone Age South African sites, there has been no evidence of the use of milk as a chemical binding agent until this discovery, she said.

A paper on the subject was published online June 30 in PLOS ONE. Co-authors were from the Italian Institute of Paleontology in Rome, Italy; the University of Geneva in Switzerland; the University of Pisa in Italy; the University of Monte St. Angelo in Naples, Italy; and the University of Oxford in England. The excavation was directed by Professor Lyn Wadley of the University of Witwatersrand, also a paper co-author.

Cattle were not domesticated in South Africa until 1,000 to 2,000 years ago, said Villa. Wild South African bovids are known to separate from the herd when giving birth and usually attempt to hide their young, a behavior that may have made them easy prey for experienced Middle Stone Age hunters, she said.

The dried paint compound is preserved on the stone flake that may have been used as a mixing implement to combine ochre and milk, or as an applicator, said Villa. The team used several high-tech chemical and elemental analyses to verify the presence of casein, the major protein of milk, on the flake.

At both African and European archaeological sites, scientists have found evidence of ochre -- a natural pigment containing iron oxide than can range from yellow and orange to red and brown -- dating back 250,000 years. By 125,000 years ago, there is evidence ochre was being ground up to produce a paint powder in South Africa.

Read more at Science Daily

New model of cosmic stickiness favors 'Big Rip' demise of universe

The universe can be a very sticky place, but just how sticky is a matter of debate.

That is because for decades cosmologists have had trouble reconciling the classic notion of viscosity based on the laws of thermodynamics with Einstein's general theory of relativity. However, a team from Vanderbilt University has come up with a fundamentally new mathematical formulation of the problem that appears to bridge this long-standing gap.

The new math has some significant implications for the ultimate fate of the universe. It tends to favor one of the more radical scenarios that cosmologists have come up with known as the "Big Rip." It may also shed new light on the basic nature of dark energy.

The new approach was developed by Assistant Professor of Mathematics Marcelo Disconzi in collaboration with physics professors Thomas Kephart and Robert Scherrer and is described in a paper published earlier this year in the journal Physical Review D.

"Marcelo has come up with a simpler and more elegant formulation that is mathematically sound and obeys all the applicable physical laws," said Scherrer.

The type of viscosity that has cosmological relevance is different from the familiar "ketchup" form of viscosity, which is called shear viscosity and is a measure of a fluid's resistance to flowing through small openings like the neck of a ketchup bottle. Instead, cosmological viscosity is a form of bulk viscosity, which is the measure of a fluid's resistance to expansion or contraction. The reason we don't often deal with bulk viscosity in everyday life is because most liquids we encounter cannot be compressed or expanded very much.

Disconzi began by tackling the problem of relativistic fluids. Astronomical objects that produce this phenomenon include supernovae (exploding stars) and neutron stars (stars that have been crushed down to the size of planets).

Scientists have had considerable success modeling what happens when ideal fluids -- those with no viscosity -- are boosted to near-light speeds. But almost all fluids are viscous in nature and, despite decades of effort, no one has managed to come up with a generally accepted way to handle viscous fluids traveling at relativistic velocities. In the past, the models formulated to predict what happens when these more realistic fluids are accelerated to a fraction of the speed of light have been plagued with inconsistencies: the most glaring of which has been predicting certain conditions where these fluids could travel faster than the speed of light.

"This is disastrously wrong," said Disconzi, "since it is well-proven experimentally that nothing can travel faster than the speed of light."

These problems inspired the mathematician to re-formulate the equations of relativistic fluid dynamics in a way that does not exhibit the flaw of allowing faster-than-light speeds. He based his approach on one that was advanced in the 1950s by French mathematician André Lichnerowicz.

Next, Disconzi teamed up with Kephart and Scherrer to apply his equations to broader cosmological theory. This produced a number of interesting results, including some potential new insights into the mysterious nature of dark energy.

In the 1990s, the physics community was shocked when astronomical measurements showed that the universe is expanding at an ever-accelerating rate. To explain this unpredicted acceleration, they were forced to hypothesize the existence of an unknown form of repulsive energy that is spread throughout the universe. Because they knew so little about it, they labeled it "dark energy."

Most dark energy theories to date have not taken cosmic viscosity into account, despite the fact that it has a repulsive effect strikingly similar to that of dark energy. "It is possible, but not very likely, that viscosity could account for all the acceleration that has been attributed to dark energy," said Disconzi. "It is more likely that a significant fraction of the acceleration could be due to this more prosaic cause. As a result, viscosity may act as an important constraint on the properties of dark energy."

Another interesting result involves the ultimate fate of the universe. Since the discovery of the universe's run-away expansion, cosmologists have come up with a number of dramatic scenarios of what it could mean for the future.

One scenario, dubbed the "Big Freeze," predicts that after 100 trillion years or so the universe will have grown so vast that the supplies of gas will become too thin for stars to form. As a result, existing stars will gradually burn out, leaving only black holes which, in turn, slowly evaporate away as space itself gets colder and colder.

An even more radical scenario is the "Big Rip." It is predicated on a type of "phantom" dark energy that gets stronger over time. In this case, the expansion rate of the universe becomes so great that in 22 billion years or so material objects begin to fall apart and individual atoms disassemble themselves into unbound elementary particles and radiation.

The key value involved in this scenario is the ratio between dark energy's pressure and density, what is called its equation of state parameter. If this value drops below -1 then the universe will eventually be pulled apart. Cosmologists have called this the "phantom barrier." In previous models with viscosity the universe could not evolve beyond this limit.

In the Desconzi-Kephart-Scherrer formulation, however, this barrier does not exist. Instead, it provides a natural way for the equation of state parameter to fall below -1.

"In previous models with viscosity the Big Rip was not possible," said Scherrer. "In this new model, viscosity actually drives the universe toward this extreme end state."

Read more at Science Daily

Quantum teleportation? Producing spin-entangled electrons

A team from the RIKEN Center for Emergent Matter Science, along with collaborators from several Japanese institutions, have successfully produced pairs of spin-entangled electrons and demonstrated, for the first time, that these electrons remain entangled even when they are separated from one another on a chip. This research could contribute to the creation of futuristic quantum networks operating using quantum teleportation, which could allow information contained in quantum bits-qubits-to be shared between many elements on chip, a key requirement to scale up the power of a quantum computer. The ability to create non-local entangled electron pairs -- known as Einstein-Podolsky-Rosen pairs -- on demand has long been a dream.

Russell Deacon, who carried out the work, says, "We set out to demonstrate that spin-entangled electrons could be reliably produced. So far, researchers have been successful in creating entangled photons, since photons are extremely stable and do not interact. Electrons, by contrast, are profoundly affected by their environment. We chose to try to show that electrons can be entangled through their spin, a property that is relatively stable."

To perform the feat, Deacon and his collaborators began the painstaking work of creating a tiny device, just a few hundred nanometers in size. The idea was to take a Cooper pair -- a pair of electrons that allows electricity to flow freely in superconductors -- and get them, while tunneling -- a quantum phenomenon -- across a junction between two superconductor leads, to pass through two separate "quantum dots" -- small crystals that have quantum properties. "If we could detect a superconducting current, this would mean that the electrons, which can be used as quantum bits -- the qubits, or bits used in quantum computing -- remain entangled even when they have been separated between the quantum dots. We confirm this separation by measuring a superconducting current that develops when they split and are recombined in the second lead."

The quantum dots, each around 100 nanometers in size, were grown at random positions on a semiconductor chip. This chip was painstakingly examined using an atomic force microscope to discover pairs of dots that were close enough that they might function properly. "We observed thousands of dots and identified around a hundred that were suitable. From these we made around twenty devices. Of those just two worked."

By measuring the superconducting current, the team was able to show clearly that the spin of the electrons remained entangled as they passed through the separate quantum dots. "Since we have demonstrated that the electrons remain entangled even when separated," says Deacon, "this means that we could now use a similar, albeit more complex, device to prepare entangled electron pairs to teleport qubit states across a chip."

Read more at Science Daily

Hermaphrodite Worm Has Sex With Its Head

One of the most unusual methods of reproduction has just been observed in a flatworm that uses its needle-like penis to stab itself in the head, which leads to egg fertilization.

The method of reproduction in the free-living flatworm, Macrostomum hystrix, exemplifies “selfing.” As outlined in a new paper in the Proceedings of the Royal Society B, selfing is when an individual can self-fertilize or self-pollinate.

It “occurs in a broad range of hermaphroditic plants and animals, and is often thought to evolve as a reproductive assurance strategy under ecological conditions that disfavor or prevent (breeding with an unrelated species),” according to lead author Steven Ramm of the University of Basel and his team. Hermaphrodites are people, plants or animals that have both male and female sexual organs or other sexual characteristics.

The flatworm that Ramm and his colleagues studied is indeed a hermaphrodite -- its blob-resembling body produces both eggs and sperm. In addition to selfing, it can also reproduce with another flatworm. The process in which the penis shoots sperm, hypodermic insemination, sounds more like a vaccination at a doctor’s office than mating.

The researchers, however, explained, “Hypodermic insemination occurs when, rather than being directly transferred to the female reproductive tract during mating, sperm are injected following traumatic wounding of the mating partner, usually through the body wall into some extra-genital location.”

The wounded worms later heal.

For selfing, the flatworms can inject their “own sperm into their anterior body region, including into their own head,” according to the researchers. Observing this process using high magnification, the scientists further noted that the sperm appear to migrate and fertilize an egg located within the flatworm’s body. Reproduction then follows.

Read more at Discovery News

Gay Rights Movement: What's Next?

In a historic decision last week in the case of Obergefell v. Hodges, the Supreme Court decided in a 5-4 ruling that gay marriage would be legal nationwide. The move prompted celebrations across the United States following a historic day in the LGBT rights movement.

Although gay marriage is the issue most often in the public eye when it comes to LGBT rights, given its status as a political hot button issue over the past couple of decades, the legalization of gay marriage is by no means the end of the fight for LGBT equality.

Anti-Discrimination Laws

In the United States, employers are prohibited on the federal level from discriminating against potential hires on the basis of race, gender, age and medical conditions. There is currently no federal law that consistently prevents employment discrimination based on sexual orientation or gender identity. As the Human Rights Council notes, 29 states have no protections in place for sexual orientation and 32 offer no legal recourse for discrimination against gender identity in the workplace.

The story is similar with housing discrimination in neighborhoods or by owners, when same-sex couples try to rent or buy a property.

Both states and the U.S. Congress have passed religious objection laws, such as the Religious Freedom Restoration Act, which opponents insist allows discrimination against LGBT people. Business owners, for example, could cite religious objections as a reason not to allow transactions with same-sex couples.

Some measure of progress, however, is seen in the reaction these types of laws generate when states adopt them. The most recent legislative effort out of Indiana earlier this year sparked a surprisingly wide-reaching controversy for a state that seldom makes national headlines. Companies threatened to cease business with the state; other governors refused to send employees of their states to Indiana for business travel; and celebrities and citizens alike took to social media to express their frustrations with the law.

Hate Crime Laws

Social acceptance of LGBT community members climbs higher every few years, but lesbian, gay and transsexual people encounter a disproportionately higher rate of violence than other Americans.

In the latest Hate Crime Statistics Report, produced by the FBI at the end of last year, out of 5,922 single-bias hate crimes reported in 2013, over 20 percent were on the basis of sexual orientation or gender identity.

Twenty states have no laws on the books for hate crimes specifically targeting LGBT individuals. In 2009, Congress passed the Matthew Shepard and James Byrd, Jr. Hate Crimes Prevention Act, which expanded federal hate crime laws to include gender, sexual orientation and gender identity.

LGBT Homelessness

LGBT individuals may encounter violence from total strangers, but they can also fall victim to abuse at home that eventually leads them to lose their economic security. Parents and guardians who choose not to accept the identities of their sons and daughters may force their children out of the home. Or the LGBT person could feel compelled to run away to escape such an environment.

According to the Center for American Progress, of the approximately 1.6 million to 2.8 million homeless youths on America’s streets, between 20 and 40 percent identify as LGBT. The average age of a gay homeless youth in New York is around 14 years, while the average age for a transgender homeless youth is just 13 years. Some 58 percent of LGBT homeless youth also report being victims of sexual assault.

Read more at Discovery News

The US, Brazil and China All Set Major Climate Goals

The world got a major dose of climate clarity on Tuesday. The United States, Brazil and China — three of the world’s top greenhouse gas emitters — all released major commitments to reduce or at least slow their greenhouse gas emissions, protect forests and ramp up their use of renewable energy.

The flurry of activity comes with five months to go until major climate talks in Paris. Those talks are considered critical for a global climate agreement and Tuesday’s news indicates a growing level of commitment to reduce emissions and the impacts of climate change.

The day started with a bilateral commitment between President Obama and his Brazilian counterpart, President Dilma Rousseff, on clean energy. Capping two days of discussions, the two leaders announced that their countries will aim to get 20 percent of their electricity from non-hydropower renewables by 2030. The exclusion of hydropower is notable because of it can be a major source of methane emissions.

The U.S. currently gets 13 percent of its electricity from renewables but almost half of that comes from hydropower. Brazil also relies heavily on hydropower for electricity generation, but wind is the cheapest form of new power generation capacity in Brazil. Though wind power is currently a smaller portion of Brazil’s overall energy mix, its low cost means it will likely be crucial to meeting the 2030 goal.

Beyond renewables, Brazil also agreed to restore nearly 30 million acres of forests. That’s only a portion of the 148 million acres of deforestation that have happened in Brazil since 1970, but still represents a major climate benefit given tropical forests’ ability to sequester carbon dioxide out of the atmosphere. The Amazon currently sequesters up to a quarter of all human carbon dioxide emissions.

In a case of dueling climate announcements, China also formally submitted its pledge as part of the United Nations climate process. That pledge confirms that China will peak its greenhouse gas emissions by 2030, a goal it laid out late last year in a bilateral agreement with the U.S.

But the new document reveals that China plans to reduce the intensity of its emissions by up to 65 percent, a move that could lead to a smaller emissions’ peak than previously estimated. The document clocks in at 16 pages and provides rich details about how China will meet its climate goals. That includes doubling current wind and nearly quadrupling solar power generating capacity and implementing a national carbon market.

“It is very detailed. I think that’s terrific and is a good sign,” Erika Rosenthal, an attorney with Earthjustice’s international program, said. “When China commits to doing something, they have mechanisms to make sure that that planning comes to fruition.”

China is already the global leader in clean energy investments, with $89 billion invested in clean energy projects in 2014. A recent analysis suggests that China will see an additional $3.4 trillion in clean energy investments through 2040. Coal use also fell in 2014, the first time that’s happened in 14 years, indicating that China could be on the path to peaking earlier than expected.

Read more at Discovery News

Woman Unearths 8.52-Carat Diamond at Arkansas Park

One of the nation’s most unusual tourist attractions is Crater of Diamonds State Park in Arkansas, which bills itself as the only diamond-producing site in the world where ordinary folks actually can dig for diamonds themselves — and keep whatever they find. Park visitors get to peruse a 37.5-acre field that’s actually the eroded surface of an ancient, gem-bearing volcanic crater. Park officials make the search even easier by occasionally plowing the field to help bring the diamonds to the surface. For $6 plus a $30 deposit, they’ll even rent you a wooden screen and bucket so that you can sift though the soil.

We’re guessing that the park will be getting an increased number of visitors, after a Colorado woman named Bobbie Oskarson found an 8.52-carat white diamond there.

According to a State Parks of Arkansas press release, Oskarson was poking around the southwest corner of the diamond field, an area known as the “Pig Pen” because it’s so muddy. She was 20 minutes into her search when she found the diamond in some scoops of dirt that she dug out from a small mound. At first, she thought it might just be a quartz crystal because of its elongated shape, but the park staff eventually confirmed for her that she’d discovered a genuine treasure.

The diamond is about three-quarters of an inch long and about the circumference of a No. 2 pencil. A park staffer described it as “absolutely stunning, sparkling with a metallic shine, and appears to be an unbroken, capsule-shaped crystal. It features smooth, curved facets, a characteristic shared by all unbroken diamonds from the Crater of Diamonds.”

Oskarso named her gem the Esperanza Diamond, which is both her niece’s name and the Spanish word for “hope.” She has indicated that she’ll keep the gem, instead of selling it. Though sizable, it’s only the fifth biggest diamond ever found at the park. The biggest was the white 16.37-carat Amarillo Starlight found in 1975 by W.W. Johnson of Amarillo, Texas. While there isn’t a reliable estimate of the Esperanza’s value, CNN reported that another large diamond found at the park sold for $150,000 in 1971 and would be worth about $800,000 today.

More than 200 other certified diamonds have been found at the park already in 2015. Here’s a basic primer on how to hunt for them.

From Discovery News

'Centipede from Hell' Found in World's Deepest Caves

Lurking in some of the world’s deepest caves is the aptly named Hades centipede, just discovered in Croatia.

The centipede, whose name refers to the Greek god of the underworld, is a top predator in caves that are located nearly 4,700 feet beneath the Earth’s surface.

“When I first saw the animal and its striking appearance, I immediately realized that this is a new, hitherto unnamed … species,” said lead author Pavel Stoev of the National Museum of Natural History, Sofia, in a statement. Stoev noted the centipede is highly adapted to the cave environment.

The centipede, Geophilus hadesi, was found in three caves at Velebit Mountain. The Lukina jama-Trojama cave system at the site is currently ranked as being the 15th deepest cave in the world. (Krubera Cave in Abkhazia, Georgia, is the world’s deepest cave, reaching a depth of 5,610 feet.)

Within its dark, mysterious habitat, the carnivorous Hades centipede hunts for prey such as insects. Note that centipedes are not insects themselves, because they have more than six legs. They are, however, classified as being arthropods, which is the large phylum that also includes insects, as well as spiders and crustaceans.

The Hades centipede, unlike centipedes that you might find in your garden, has elongated antennae, trunk segments and leg claws. All are adaptations to life at tremendous depths. The centipede also has powerful jaws bearing poison glands. If the centipede grasps prey with its claws, the predator can then inflict a deadly bite.

Yet another new centipede species, named Persephone after the Greek queen of the underworld, was also found in deep caves.

Read more at Discovery News

Making new materials with micro-explosions

Scientists have made exotic new materials by creating laser-induced micro-explosions in silicon, the common computer chip material.

The new technique could lead to the simple creation and manufacture of superconductors or high-efficiency solar cells and light sensors, said leader of the research, Professor Andrei Rode, from The Australian National University (ANU).

"We've created two entirely new crystal arrangements, or phases, in silicon and seen indications of potentially four more," said Professor Rode, a laser physicist at the ANU Research School of Physics and Engineering (RSPE).

"Theory predicts these materials could have very interesting electronic properties, such as an altered band gap, and possibly superconductivity if properly doped."

By focusing lasers onto silicon buried under a clear layer of silicon dioxide, the group have perfected a way to reliably blast tiny cavities in the solid silicon. This creates extremely high pressure around the explosion site and forms the new phases.

The phases have complex structures, which took the team of physicists from ANU and University College London a year to understand.

Using a combination of electron diffraction patterns and structure predictions, the team discovered the new materials have crystal structures that repeat every 12, 16 or 32 atoms respectively, said Professor Jim Williams, from the Electronic Material Engineering group at RSPE.

"The micro-explosions change silicon's simplicity to much more complex structures, which opens up possibility for unusual and unexpected properties," he said.

These complex phases are often unstable, but the small size of the structures means the materials cool very quickly and solidify before they can decay, said Professor Eugene Gamaly, also from the ANU Research School of Physics and Engineering. The new crystal structures have survived for more than a year now.

"These new discoveries are not an accident, they are guided by a deep understanding of how lasers interact with matter," he said.

Conventional methods for creating materials with high pressure use tiny diamond anvils to poke or squeeze materials. However, the ultra-short laser micro-explosion creates pressures many times higher than the strength of diamond crystal can produce.

Read more at Science Daily

Physicists shatter stubborn mystery of how glass forms

A physicist at the University of Waterloo is among a team of scientists who have described how glasses form at the molecular level and provided a possible solution to a problem that has stumped scientists for decades.

Their simple theory is expected to open up the study of glasses to non-experts and undergraduates as well as inspire breakthroughs in novel nano materials.

The paper published by physicists from the University of Waterloo, McMaster University, ESPCI ParisTech and Université Paris Diderot appeared in the journal, Proceedings of the National Academy of Sciences (PNAS).

Glasses are much more than silicon-based materials in bottles and windows. In fact, any solid without an ordered, crystalline structure -- metal, plastic, a polymer -- that forms a molten liquid when heated above a certain temperature is a glass. Glasses are an essential material in technology, pharmaceuticals, housing, renewable energy and increasingly nano electronics.

"We were surprised -- delighted -- that the model turned out to be so simple," said author James Forrest, a University Research Chair and professor in the Faculty of Science. "We were convinced it had already been published."

The theory relies on two basic concepts: molecular crowding and string-like co-operative movement. Molecular crowding describes how molecules within glasses move like people in a crowded room. As the number of people increase, the amount of free volume decreases and the slower people can move through the crowd. Those people next to the door are able to move more freely, just as the surfaces of glasses never actually stop flowing, even at lower temperatures.

The more crowded the room, the more you rely on the co-operative movement with your neighbours to get where you're going.

Likewise, individual molecules within a glass aren't able to move totally freely. They move with, yet are confined by, strings of weak molecular bonds with their neighbours.

Theories of crowding and cooperative movement are decades old. This is the first time scientists combined both theories to describe how a liquid turns into a glass.

"Research on glasses is normally reserved for specialists in condensed matter physics," said Forrest, who is also an associate faculty member at Perimeter Institute for Theoretical Physics and a member of the Waterloo Institute for Nanotechnology. "Now a whole new generation of scientists can study and apply glasses just using first-year calculus."

Read more at Science Daily

China's Great Wall Is Slowly Disappearing

Around 30 percent of China's Ming-era Great Wall has disappeared over time as adverse natural conditions and reckless human activities -- including stealing the bricks to build houses -- erode the UNESCO World Heritage site, state media reported.

The Great Wall is not a single unbroken structure but stretches for thousands of miles in sections, from Shanhaiguan on the east coast to Jiayuguan in the windswept sands on the edge of the Gobi desert.In places it is so dilapidated that estimates of its total length vary from 5,600 to 13,000 miles, depending on whether missing sections are included. Despite its length it is not, as is sometimes claimed, visible from space.

Construction first begun in the third century BC, but nearly 4,000 miles were built in the Ming Dynasty of 1368-1644, including the much-visited sectors north of the capital Beijing.

Of that, 1,200 miles has melted away over the centuries, the Beijing Times reported.

Some of the construction weathered away, while plants growing in the walls have accelerated the decay, said the report Sunday, citing a survey last year by the Great Wall of China Society.

"Even though some of the walls are built of bricks and stones, they cannot withstand the perennial exposure to wind and rain," the paper quoted Dong Yaohui, a vice president of the society, as saying.

"Many towers are becoming increasingly shaky and may collapse in a single rain storm in summer."

Tourism and local residents' activities are also damaging the longest human construction in the world, the paper added.

Poor villagers in Lulong county in the northern province of Hebei used to knock thick grey bricks from a section of wall in their village to build homes, and slabs engraved with Chinese characters were sold for 30 yuan ($4.80) each by local residents, it said.

Read more at Discovery News

Venus to Hug Jupiter in Crazy-Close Conjunction

For the next few nights, be sure to make a special effort to go outside at twilight and look West — if you live in the Northern Hemisphere and have clear skies. You see those two bright stars really (and I mean really) close to one another? Those aren’t stars, they’re two planets, Venus and Jupiter, making a wonderfully close pass in the night sky.

Known as a conjunction, the pair are set to come less than 1/3 of a degree apart on the evening of June 30, but for the next week you’ll be able to see the evening pairing within 3° of one another. For the past few days they have been slowly creeping up on one another, becoming the focus of skywatchers.

As noted by Sky & Telescope magazine, conjunctions between Venus and Jupiter aren’t particularly rare — indeed, the two worlds met even in our skies last August and will do again in October — but they are a stunning sight. As an added bonus, if you you’re armed with a telescope or powerful pair of binoculars, you may be able to pick out both Venus’ and Jupiter’s crescents.

So get out there and watch tonight’s celestial dance just after sunset. Weather permitting, you won’t be disappointed.

For more details behind the conjuntion and opportunities for viewing, see this handy Astronomy.com guide.

From Discovery News

Spiral arms cradle baby terrestrial planets

New work from Carnegie's Alan Boss offers a potential solution to a longstanding problem in the prevailing theory of how rocky planets formed in our own Solar System, as well as in others. The snag he's untangling: how dust grains in the matter orbiting a young protostar avoid getting dragged into the star before they accumulate into bodies large enough that their own gravity allows them to rapidly attract enough material to grow into planets. The study is published by The Astrophysical Journal.

In the early stages of their formation, stars are surrounded by rotating disks of gas and dust. The dust grains in the disk collide and aggregate to form pebbles, which grow into boulders, and so on increasing in size through planetesimals, planetary embryos, and finally rocky terrestrial planets. But there are some difficult outstanding questions raised by this theory. One of these is that the pressure gradient of the gas in the disk would create a headwind that would spiral the pebbles and boulders inward toward the young protostar, where they would be destroyed.

The problem is most acute in bodies that are between 1 and 10 meters in radius, because they would be most susceptible to the gas drag. If too many particles in this size range were lost, there wouldn't be enough remaining to collide with each other and accumulate into planetesimals and, eventually, planets.

Observations of young stars that are still surrounded by their gas disks demonstrate that those similar in size to our own Sun often undergo periodic explosive bursts, about 100 years in duration, during which the star's luminosity increases. More importantly, these events can be linked to a period of gravitational instability in the disk. Boss's new work shows that such a phase can scatter the at-risk 1- to 10-meter bodies outward away from the developing star, rather than inward toward it.

Recent work has shown the presence of spiral arms around young stars, similar to those thought to be involved in the short-term disruptions in the disk. The gravitational forces of these spiral arms could scatter outward the problematic boulder-sized bodies, allowing them to accumulate rapidly to form planetesimals large enough that gas drag is no longer a problem. Boss's modeling techniques hone in on the idea that spiral arms might be able to answer the question of how a developing solar system avoids losing too many larger bodies before the boulders have a chance to grow into something bigger.

"This work shows that boulder-sized particles could, indeed, be scattered around the disk by the formation of spiral arms and then avoid getting dragged into the protostar at the center of the developing system," Boss explained. "Once these bodies are in the disk's outer regions, they are safe and able to grow into planetesimals."

Read more at Science Daily

The peaks and valleys of silicon

When the new iPhone came out, customers complained that it could be bent -- but what if you could roll up your too big 6 Plus to actually fit in your pocket? That technology might be available sooner than you think, based on the work of USC Viterbi engineers.

For many decades, silicon has been the heart of modern electronics -- but as a material, it has its limits. As our devices get smaller and smaller, the basic unit of these devices, a transistor, must also get tinier and tinier. Bottom line: the size of the silicon transistor is reaching its physical limit. As silicon devices are based on what is called a top-down cutting method, it is increasingly difficult for silicon to be made even smaller. Consumers also demand phones to be lighter, faster, smaller, more flexible, wearable, bendable, etc. Yet silicon is also rigid -- one can't bend your smart phone or computer. These physical limitations have driven the race for new materials that can be used as semiconductors in lieu of silicon.

The demand for a silicon material aided the discovery of graphene, a single layer of graphite -- which won the Nobel Prize in Physics in 2010. Since this time, scientists and engineers have developed many two-dimensional (2D) material innovations -- layered materials with the thickness of only one atom or a few atoms. One such layered 2D material is black arsenic phosphorus. Now, a team of scientists at USC Viterbi, in collaboration with Technische Universität München, Germany, Universität Regensburg, Germany, and Yale University, have developed a new method to synthesize black arsenic-phosphorus without high pressure. This method demands less energy and is cheaper, and the synthesized materials have some incredible new properties.

The innovation, developed by USC Viterbi researchers, including Bilu Liu, the paper's lead author and postdoctoral researcher; Ahamad Abbas, graduate student; Han Wang, assistant professor; Rohan Dhall, graduate student; Stephen B. Cronin, associate professor; Mingyuan Ge, research assistant; Xin Fang, graduate student; and Professor Chongwu Zhou of the Ming Hsieh Department of Electrical Engineering, in concert with their collaborators, is documented in a paper titled "Black Arsenic-Phosphorus: Layered Anisotropic Infrared Semiconductors with Highly Tunable Compositions and Properties." The paper appeared in Advanced Materials on June 25, 2015.

What the researchers are most excited about is the ability to adjust the electronic and optical properties of these materials to a range that cannot be achieved by any other 2D materials thus far. This includes manipulating the materials' chemical compositions during materials synthesis and the materials' ability to sense long wavelength infrared (LWIR) waves due to their small energy gaps. This particular electromagnetic spectral range of LWIR is important for a range of applications such as LIDAR (light radar) systems, basically because LWIR waves are highly transparent in earth atmosphere. This wave range also has great application for the soldiers in the military who rely on infrared thermal imaging technology and for flexible night vision glasses. Another intriguing aspect of these new layeredsemiconductors is their anisotropic electronic and optical properties, which means the materials have different properties along x and y direction in the same plane. The researchers believe these are marked improvement from existing materials and devices and would lead to unique applications.

Read more at Science Daily