Itsy bitsy spider: Fear of spiders and snakes is deeply embedded in us

When the babies saw a snake or a spider (second row) instead of a flower or a fish (first row) of the same size and colour, their pupils enlarged significantly (red versus green curve). This is a distinct signal that they felt stressed looking at these animals.

Presumably, in industrialized countries, especially in middle Europe, most people have never come across a poisonous spider or snake in the wild. In most of this countries there are nearly no spiders or snakes that pose a threat to humans. Nevertheless, there are few people that would not shiver at the thought of a spider crawling up their arm, however harmless it may be.

This fear can even develop into anxiety which limits a person's daily life. Such people are always on edge and cannot enter a room before it is declared "spider free" or cannot venture out into nature for sheer fear that they may encounter a snake. In developed countries one to five per cent of the population are affected by a real phobia of these creatures.

Until now, it was not clear where this widespread aversion or anxiety stems from. While some scientists assume that we learn this fear from our surroundings when we are a child, others suppose that it is innate. The drawback of most previous studies on this topic was that they were conducted with adults or older children -- making it hard to distinguish which behaviour was learnt and which was inborn. Such studies with children only tested whether they spot spiders and snakes faster than harmless animals or objects, not whether they show a direct physiological fear reaction.

Scientists at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in Leipzig and the Uppsala University, Sweden, recently made a crucial observation: Even in infants a stress reaction is evoked when they see a spider or a snake. And this already at the age of six months, when they are still very immobile and have had little opportunity to learn that these animals can be dangerous.

"When we showed pictures of a snake or a spider to the babies instead of a flower or a fish of the same size and colour, they reacted with significantly bigger pupils," says Stefanie Hoehl, lead investigator of the underlying study and neuroscientist at MPI CBS and the University of Vienna. "In constant light conditions this change in size of the pupils is an important signal for the activation of the noradrenergic system in the brain, which is responsible for stress reactions. Accordingly, even the youngest babies seem to be stressed by these groups of animals."

"We conclude that fear of snakes and spiders is of evolutionary origin. Similar to primates, mechanisms in our brains enable us to identify objects as 'spider' or 'snake' and to react to them very fast. This obviously inherited stress reaction in turn predisposes us to learn these animals as dangerous or disgusting. When this accompanies further factors it can develop into a real fear or even phobia. "A strong panicky aversion exhibited by the parents or a genetic predisposition for a hyperactive amygdala, which is important for estimating hazards, can mean that increased attention towards these creatures becomes an anxiety disorder."

Interestingly, it is known from other studies that babies do not associate pictures of rhinos, bears or other theoretically dangerous animals with fear. "We assume that the reason for this particular reaction upon seeing spiders and snakes is due to the coexistence of these potentially dangerous animals with humans and their ancestors for more than 40 to 60 million years -- and therefore much longer than with today's dangerous mammals. The reaction which is induced by animal groups feared from birth could have been embedded in the brain for an evolutionarily long time.

Read more at Science Daily

Life goes on for marine ecosystems after cataclysmic mass extinction

This is s dead staghorn Coral.

One of the largest global mass extinctions did not fundamentally change marine ecosystems, scientists have found.

An international team of scientists, including Dr Alex Dunhill from the University of Leeds, has found that although the mass extinction in the Late Triassic period wiped out the vast proportion of species, there appears to be no drastic changes to the way marine ecosystems functioned.

Lead author Dr Dunhill, from the School of Earth and Environment at Leeds, said: "While the Late Triassic mass extinction had a big impact on the overall number of marine species, there was still enough diversity among the remaining species that the marine ecosystem was able to function in the same way it had before."

"We're not saying nothing happened," said co-author Dr William Foster, a palaeontologist from the Jackson School of Geosciences at the University of Texas at Austin. "Rather, global oceans in the extinction's aftermath were a bit like a ship manned by a skeleton crew -- all stations were operational, but manned by relatively few species."

The Late Triassic mass extinction occurred 201 million years ago. Nearly 50 per cent of life on Earth died out as a result of huge volcanic eruptions. The volcanic activity caused high levels of greenhouse gases in the atmosphere which led to rapid global warming. The eruptions are also associated with the break-up of the supercontinent Pangaea and the opening of the Atlantic Ocean

The team compared marine ecosystem across the Late Triassic mass extinction event by examining fossils from the Middle Triassic to Middle Jurassic -- a 70 million-year span. They classified the lifestyle of different ocean-dwelling animals by how they moved, where they lived and how they fed.

They were then able to determine that none of these lifestyles had completely disappeared due to the extinction event, which preserved the marine ecosystem.

Their results, published today in Palaeontology, showed that while the extinction did not result in a global marine ecological shift, it had profound regional and environmental effects and had an extreme impact on specific ocean ecosystems.

Dr Dunhill said: "One of the great marine casualties of the Late Triassic were stationary reef-dwelling animals, such as corals. When we examined the fossil record we saw that while the marine ecosystem continued to function as a whole, it took over 20 million years for tropical reef ecosystems to recover from this environmental cataclysm.

"Reef ecosystems are the most vulnerable to rapid environmental change. The effect of the Late Triassic greenhouse gases on marine ecosystems is not so different from what you see happening to coral reefs suffering from increasing ocean temperatures today."

Co-author, Professor Richard Twitchett, from the Natural History Museum in London said: "Understanding the extent of reef collapse during past extinctions may help us predict what is in store for our modern marine ecosystems.

Read more at Science Daily

New NASA study improves search for habitable worlds

This is a plot of what the sea ice distribution could look like on a synchronously rotating ocean world. The star is off to the right, blue is where there is open ocean, and white is where there is sea ice.

New NASA research is helping to refine our understanding of candidate planets beyond our solar system that might support life.

"Using a model that more realistically simulates atmospheric conditions, we discovered a new process that controls the habitability of exoplanets and will guide us in identifying candidates for further study," said Yuka Fujii of NASA's Goddard Institute for Space Studies (GISS), New York, New York and the Earth-Life Science Institute at the Tokyo Institute of Technology, Japan, lead author of a paper on the research published in the Astrophysical Journal Oct. 17.

Previous models simulated atmospheric conditions along one dimension, the vertical. Like some other recent habitability studies, the new research used a model that calculates conditions in all three dimensions, allowing the team to simulate the circulation of the atmosphere and the special features of that circulation, which one-dimensional models cannot do. The new work will help astronomers allocate scarce observing time to the most promising candidates for habitability.

Liquid water is necessary for life as we know it, so the surface of an alien world (e.g. an exoplanet) is considered potentially habitable if its temperature allows liquid water to be present for sufficient time (billions of years) to allow life to thrive. If the exoplanet is too far from its parent star, it will be too cold, and its oceans will freeze. If the exoplanet is too close, light from the star will be too intense, and its oceans will eventually evaporate and be lost to space. This happens when water vapor rises to a layer in the upper atmosphere called the stratosphere and gets broken into its elemental components (hydrogen and oxygen) by ultraviolet light from the star. The extremely light hydrogen atoms can then escape to space. Planets in the process of losing their oceans this way are said to have entered a "moist greenhouse" state because of their humid stratospheres.

In order for water vapor to rise to the stratosphere, previous models predicted that long-term surface temperatures had to be greater than anything experienced on Earth -- over 150 degrees Fahrenheit (66 degrees Celsius). These temperatures would power intense convective storms; however, it turns out that these storms aren't the reason water reaches the stratosphere for slowly rotating planets entering a moist greenhouse state.

"We found an important role for the type of radiation a star emits and the effect it has on the atmospheric circulation of an exoplanet in making the moist greenhouse state," said Fujii. For exoplanets orbiting close to their parent stars, a star's gravity will be strong enough to slow a planet's rotation. This may cause it to become tidally locked, with one side always facing the star -- giving it eternal day -- and one side always facing away -giving it eternal night.

When this happens, thick clouds form on the dayside of the planet and act like a sun umbrella to shield the surface from much of the starlight. While this could keep the planet cool and prevent water vapor from rising, the team found that the amount of near-Infrared radiation (NIR) from a star could provide the heat needed to cause a planet to enter the moist greenhouse state. NIR is a type of light invisible to the human eye. Water as vapor in air and water droplets or ice crystals in clouds strongly absorbs NIR light, warming the air. As the air warms, it rises, carrying the water up into the stratosphere where it creates the moist greenhouse.

This process is especially relevant for planets around low-mass stars that are cooler and much dimmer than the Sun. To be habitable, planets must be much closer to these stars than our Earth is to the Sun. At such close range, these planets likely experience strong tides from their star, making them rotate slowly. Also, the cooler a star is, the more NIR it emits. The new model demonstrated that since these stars emit the bulk of their light at NIR wavelengths, a moist greenhouse state will result even in conditions comparable to or somewhat warmer than Earth's tropics. For exoplanets closer to their stars, the team found that the NIR-driven process increased moisture in the stratosphere gradually. So, it's possible, contrary to old model predictions, that an exoplanet closer to its parent star could remain habitable.

This is an important observation for astronomers searching for habitable worlds, since low-mass stars are the most common in the galaxy. Their sheer numbers increase the odds that a habitable world may be found among them, and their small size increases the chance to detect planetary signals.

The new work will help astronomers screen the most promising candidates in the search for planets that could support life. "As long as we know the temperature of the star, we can estimate whether planets close to their stars have the potential to be in the moist greenhouse state," said Anthony Del Genio of GISS, a co-author of the paper. "Current technology will be pushed to the limit to detect small amounts of water vapor in an exoplanet's atmosphere. If there is enough water to be detected, it probably means that planet is in the moist greenhouse state."

In this study, researchers assumed a planet with an atmosphere like Earth, but entirely covered by oceans. These assumptions allowed the team to clearly see how changing the orbital distance and type of stellar radiation affected the amount of water vapor in the stratosphere. In the future, the team plans to vary planetary characteristics such as gravity, size, atmospheric composition, and surface pressure to see how they affect water vapor circulation and habitability.

Read more at Science Daily

NASA's MAVEN mission finds Mars has a twisted magnetic tail

Artist's conception of the complex magnetic field environment at Mars. Yellow lines represent magnetic field lines from the Sun carried by the solar wind, blue lines represent Martian surface magnetic fields, white sparks are reconnection activity, and red lines are reconnected magnetic fields that link the surface to space via the Martian magnetotail.

Mars has an invisible magnetic "tail" that is twisted by interaction with the solar wind, according to new research using data from NASA's MAVEN spacecraft.

NASA's Mars Atmosphere and Volatile Evolution Mission (MAVEN) spacecraft is in orbit around Mars gathering data on how the Red Planet lost much of its atmosphere and water, transforming from a world that could have supported life billions of years ago into a cold and inhospitable place today. The process that creates the twisted tail could also allow some of Mars' already thin atmosphere to escape to space, according to the research team.

"We found that Mars' magnetic tail, or magnetotail, is unique in the solar system," said Gina DiBraccio of NASA's Goddard Space Flight Center in Greenbelt, Maryland. "It's not like the magnetotail found at Venus, a planet with no magnetic field of its own, nor is it like Earth's, which is surrounded by its own internally generated magnetic field. Instead, it is a hybrid between the two." DiBraccio is project scientist for MAVEN and is presenting this research at a press briefing Thursday, Oct. 19 at 12:15pm MDT during the 49th annual meeting of the American Astronomical Society's Division for Planetary Sciences in Provo, Utah.

The team found that a process called "magnetic reconnection" must have a big role in creating the Martian magnetotail because, if reconnection were occurring, it would put the twist in the tail.

"Our model predicted that magnetic reconnection will cause the Martian magnetotail to twist 45 degrees from what's expected based on the direction of the magnetic field carried by the solar wind," said DiBraccio. "When we compared those predictions to MAVEN data on the directions of the Martian and solar wind magnetic fields, they were in very good agreement."

Mars lost its global magnetic field billions of years ago and now just has remnant "fossil" magnetic fields embedded in certain regions of its surface. According to the new work, Mars' magnetotail is formed when magnetic fields carried by the solar wind join with the magnetic fields embedded in the Martian surface in a process called magnetic reconnection. The solar wind is a stream of electrically conducting gas continuously blowing from the Sun's surface into space at about one million miles (1.6 million kilometers) per hour. It carries magnetic fields from the Sun with it. If the solar wind field happens to be oriented in the opposite direction to a field in the Martian surface, the two fields join together in magnetic reconnection.

The magnetic reconnection process also might propel some of Mars' atmosphere into space. Mars' upper atmosphere has electrically charged particles (ions). Ions respond to electric and magnetic forces and flow along magnetic field lines. Since the Martian magnetotail is formed by linking surface magnetic fields to solar wind fields, ions in the Martian upper atmosphere have a pathway to space if they flow down the magnetotail. Like a stretched rubber band suddenly snapping to a new shape, magnetic reconnection also releases energy, which could actively propel ions in the Martian atmosphere down the magnetotail into space.

Since Mars has a patchwork of surface magnetic fields, scientists had suspected that the Martian magnetotail would be a complex hybrid between that of a planet with no magnetic field at all and that found behind a planet with a global magnetic field. Extensive MAVEN data on the Martian magnetic field allowed the team to be the first to confirm this. MAVEN's orbit continually changes its orientation with respect to the Sun, allowing measurements to be made covering all of the regions surrounding Mars and building up a map of the magnetotail and its interaction with the solar wind.

Magnetic fields are invisible but their direction and strength can be measured by the magnetometer instrument on MAVEN, which the team used to make the observations. They plan to examine data from other instruments on MAVEN to see if escaping particles map to the same regions where they see reconnected magnetic fields to confirm that reconnection is contributing to Martian atmospheric loss and determine how significant it is. They also will gather more magnetometer data over the next few years to see how the various surface magnetic fields affect the tail as Mars rotates. This rotation, coupled with an ever-changing solar wind magnetic field, creates an extremely dynamic Martian magnetotail. "Mars is really complicated but really interesting at the same time," said DiBraccio.

Read more at Science Daily

Climate-Changing Volcanic Eruptions May Have Helped Topple Cleopatra

The west colonnade hall of the Temple of Isis. The construction of the temple started during the reign of Ptolemy II Philadelphus and was completed by his successor Ptolemy III Euergetes, Egypt, Ptolemaic dynasty.

It's a mystery that's perplexed Egypt scholars for hundreds of years: What ultimately caused the collapse of the 300-year Ptolemaic dynasty and the downfall of its last ruler, the queen Cleopatra?

It turns out that the answer — or part of the answer, anyway — appears to be volcanoes.

An international team of historians and climate scientists published research this week in the journal Nature Communications suggesting ancient volcanic eruptions changed the course of history in Africa and the Middle East. It's a twisty tale, concerning class revolt, ancient papyrus records, ice core samples, tropical volcanoes, and the annual flooding of the river Nile.

It helps to have a little background: The Ptolemaic dynasty in Egypt (305-30 BC) relied heavily on the seasonal flooding of the Nile for agriculture. But the Nile was famously unreliable, and when the river didn't flood, crops died, triggering famines, plagues, and social unrest.

Historians know this thanks to various artifacts that show both the history of the Nile's water levels and the history of major political crises and uprisings.

One of those historians is Joseph Manning of Yale University, who co-authored the new study with Francis Ludlow, a climate historian at Trinity College Dublin. While Manning's work focuses on Egyptian history, Ludlow's specialty is tracking major volcanic eruptions throughout history.

The idea for their unique collaboration was to compare timelines of Egyptian unrest with geological records that reveal the timing of major volcanic eruptions. Their conclusion: It's likely that violent volcanic eruptions triggered climate changes that directly impacted the Nile — which in turn may have led to the social upheaval that doomed Cleopatra and the Ptolemaic dynasty.

“My specialty, as a climate historian, is to concentrate upon how we can extract information on past climate conditions from both natural and human archives,” Ludlow told Seeker. “Natural archives might include tree rings or ice cores, and human archives would include written records and even archaeological evidence.”

This piece of papyrus from the mid-3rd century BC describes a period of famine in Egypt that occurred when the Nile River failed to flood for several years in a row. It was collected from the Egyptian city of Edfu.

Using computer simulations and historical measurements of the Nile River, Ludlow, Manning, and their colleagues discovered that poor flood years on the Nile lined up over and over again with major volcanic eruptions around the world. The evidence suggests that the volcanic activity cooled the atmosphere, suppressing rainfall and preventing the Nile from flooding.

Digging even deeper into the historical record, Manning was able to determine that volcanic eruptions preceded several major political and economic events during the Ptolemaic period. For instance, a major eruption in 247 BC was followed by a revolt that caused the army of Ptolemy III to withdraw from a Middle Eastern campaign and return home. The revolt was likely due to crop failure, which was almost certainly caused by the Nile failing to flood.

A similar scenario occurred in 44 BC, which led to an outbreak of famine and disease that weakened the rule of Cleopatra.

The researchers are quick to note that much of the cause-and-effect linkage is supposition, and that climate changes are just one of many factors that can contribute to major events in history.

“Connecting climatic changes to complex social and political events like the collapse of a dynasty needs to be done cautiously and with a full recognition of the historical context in which many other factors will also inevitably have played an important role,” Ludlow said.

Still, the concurrence of volcanic activity with Nile river failures — and subsequent civil unrest — is remarkably precise and very unlikely to be simple coincidence, researchers said. The trick is in noticing them in the first place. All the clues were there in the historical record, Manning said, but it took a team of scholars to piece them together.

“It's important to work in this truly interdisciplinary way in order to make progress,” Manning said.

Read more at Seeker

First Known Incidents of Alligators Eating Sharks Reported in American Southeast

Kansas State University postdoctoral researcher James Nifong documents widespread American alligators' predation of four species of shark like this nurse shark.

James Nifong is a biologist in the same way that Indiana Jones is an archeologist. The Kansas State University postdoctoral researcher estimates that he’s captured well over 1,000 alligators from the coastal waters of Florida and Georgia over the past 10 years, sometimes standing on the bow of a speeding fishing boat at night armed with a big hook and a headlamp.

Once a writhing alligator is hauled aboard — large, adult males range between 11 and 16 feet in length — Nifong and his fellow researchers strap it to a board, prop its mouth open with a wide circle of plastic or steel pipe, feed a hose down its throat, fill its stomach with water, and then “jiggle” the animal’s belly around until it pukes up its lunch.

Nifong’s research specialty is the eating habits of the American alligator (Alligator mississippiensis), the toothy alpha predator that inhabits much of the southeastern United States along the Atlantic and Gulf Coasts. While coastal-dwelling alligators are known to chow down on small fish, crustaceans, and unsuspecting birds, they’re also opportunistic eaters. Over the past few years, Nifong’s been trying to figure out if one particular rumor is true: Do alligators really eat sharks?

Stories have circulated for ages about deadly encounters between gators and sharks. A magazine article from 1877 in The Fishing Gazette describes an epic battle between roughly 500 alligators and untold hundreds of sharks along the coast of Jupiter, Florida. The gators gorged themselves on a school of fish trapped by a flood tide and nearby sharks were attracted by the carnage. An eyewitness described the scene: “…[the] sharks and alligators rise on the crest of the waves and fight like dogs.”

But apart from these anecdotal accounts, there was no solid proof — photos or video with exact dates and times of an event — that alligators indeed ate sharks, or vice versa.

So Nifong set out to find some.

Searching through alligator puke wasn’t likely to uncover many clues, since alligators fully digest their prey in one to three days. And even if alligators did eat sharks, it was probably a rare enough occurrence that it would take extremely good luck to capture a gator and pump its stomach within a day of eating a shark.

So Nifong cast his net wider, asking colleagues, friends, and friends of friends if they’d ever personally witnessed an alligator eating a shark or ray, both members of the Elasmobranchii family. He found a sea turtle researcher who had twice documented alligators (1997 and 1999) feeding on sharks on Wassaw Island, Georgia — but there weren’t any pictures. Darn.

But then he hit paydirt. In 2003, a US Fish and Wildlife Service staffer working in the Ding Darling National Wildlife Refuge in Sanibel, Florida, had actually photographed an eight-foot alligator attacking and engulfing a three-foot nurse shark. Here was the proof!

In a recent article in the journal Southeastern Naturalist, Nifong and co-author Russell Lowers, a wildlife biologist at the Kennedy Space Center, documented four separate encounters, recorded and in some cases photographed by field researchers, where an alligator had indeed eaten a shark or ray.

Why was this so important to prove? Because many species of sharks and rays use protected coastal estuaries and tidal rivers as nurseries for their young. And those are exactly the types of brackish environments where the four alligator attacks were documented.

“It’s really important to figure out if the juvenile sharks and rays are getting nailed by these predators and to account for that in population models,” Nifong told Seeker.

An alligator eating a bonnethead shark on Hilton Head Island, SC

Of the four shark and ray species observed in the documented attacks — nurse sharks, lemon sharks, bonnethead sharks, and Atlantic stingrays — none were endangered. But Nifong noted that the smalltooth sawfish, which is seriously endangered, lives in the same waters as that nurse shark gobbled up in Florida, and it’s also in the Elasmobranchii family.

It’s no surprise that alligators, sharks, and rays would find themselves in the same waters. Even though alligators primarily stick to freshwater and Elasmobranchii are ocean dwellers, both can handle waters ranging in salinity from 10 to 15 parts per thousand up to full strength seawater (36 ppt). The attack in Georgia, for example, happened right off the beach in pure ocean water.

Alligators lack salt glands to help regulate their body’s salinity, so long-term exposure to high-salinity waters will cause them to dehydrate, but Nifong said that he’s tracked alligators with GPS who regularly “commute” into ocean water for a “seafood buffet” before heading home to freshwater. Alligators will also drink freshwater during a rainstorm to stay hydrated in salty water.

“I’ve seen them standing with their mouth open in the marsh in the rain drinking the rainwater,” Nifong said, “as well as sipping off the top of the water column after it rained.”

Read more at Seeker

Six degrees of separation: Why it is a small world after all

It's a small world after all.

It's a small world after all -- and now science has explained why.

A study conducted by the University of Leicester and KU Leuven, Belgium, examined how small worlds emerge spontaneously in all kinds of networks, including neuronal and social networks, giving rise to the well-known phenomenon of "six degrees of separation."

Many systems show complex structures, of which a distinctive feature is small-world network organization. They arise in society as well as ecological and protein networks, the networks of the mammalian brain, and even human-built networks such as the Boston subway and the World Wide Web.

The researchers set out to examine whether this is a coincidence that such structures are so wide-spread or is there a common mechanism driving their emergence?

A study recently published in Scientific Reports by an international team of academics from the University of Leicester and KU Leuven showed that these remarkable structures are reached and maintained by the network diffusion, i.e. the traffic flow or information transfer occurring on the network.

The research presents a solution to the long-standing question of why the vast majority of networks around us (WWW, brain, roads, power grid infrastructure) might have a peculiar yet common structure: small-world topology.

The study showed that these structures emerge naturally in systems in which the information flow is accounted for in their evolution.

Nicholas Jarman, who recently completed his PhD degree at the Department of Mathematics, and is first author of the study, said: "Algorithms that lead to small-world networks have been known in scientific community for many decades. The Watts-Strogatz algorithm is a good example. The Watts-Strogatz algorithm, however, was never meant to address the problem of how small-world structure emerges through self-organisation. The algorithm just modifies a network that is already highly organised."

Professor Cees van Leeuwen, who led the research at KU Leuven said: "The network diffusion steers network evolution towards emergence of complex network structures. The emergence is effectuated through adaptive rewiring: progressive adaptation of structure to use, creating short-cuts where network diffusion is intensive while annihilating underused connections. The product of diffusion and adaptive rewiring is universally a small-world structure. The overall diffusion rate controls the system's adaptation, biasing local or global connectivity patterns, the latter providing a preferential attachment regime to adaptive rewiring. The resulting small-world structures shift accordingly between decentralised (modular) and centralised ones. At their critical transition, network structure is hierarchical, balancing modularity and centrality -- a characteristic feature found in, for instance, the human brain."

Dr Ivan Tyukin from the University of Leicester added: "The fact that diffusion over network graph plays crucial role in keeping the system at a somewhat homeostatic equilibrium is particularly interesting. Here we were able to show that it is the diffusion process, however small or big gives rise to small-world network configurations that remain in this peculiar state over long intervals of time. At least as long as we were able to monitor the network development and continuous evolution."

Alexander Gorban, Professor in Applied Mathematics, University of Leicester commented: "Small-world networks, in which most nodes are not neighbours of one another, but most nodes can be reached from every other node by a small number of steps, were described in mathematics and discovered in nature and human society long ago, in the middle of the previous century. The question, how these networks are developing by nature and society remained not completely solved despite of many efforts applied during last twenty years. The work of N. Jarman with co-authors discovers a new and realistic mechanism of emergence of such networks. The answer to the old question became much clearer! I am glad that the University of Leicester is a part of this exciting research."

From Science Daily

New tyrannosaur fossil is most complete found in Southwestern US

Toe bones, the upper jaw and snout of the fossilized remains of a tyrannosaur skeleton found in Grand Staircase-Escalante National Monument. The skeleton is the most complete of its kind found in the Southwest United States.

A remarkable new fossilized skeleton of a tyrannosaur discovered in the Bureau of Land Management's Grand Staircase-Escalante National Monument (GSENM) in southern Utah was airlifted by helicopter Sunday, Oct 15, from a remote field site, and delivered to the Natural History Museum of Utah where it will be uncovered, prepared, and studied. The fossil is approximately 76 million years old and is most likely an individual of the species Teratophoneus curriei, one of Utah's ferocious tyrannosaurs that walked western North America between 66 and 90 million years ago during the Late Cretaceous Period.

"With at least 75 percent of its bones preserved, this is the most complete skeleton of a tyrannosaur ever discovered in the southwestern US," said Dr. Randall Irmis, curator of paleontology at the Museum and associate professor in the Department of Geology and Geophysics at the University of Utah. "We are eager to get a closer look at this fossil to learn more about the southern tyrannosaur's anatomy, biology, and evolution."

GSENM Paleontologist Dr. Alan Titus discovered the fossil in July 2015 in the Kaiparowits Formation, part of the central plateau region of the monument. Particularly notable is that the fossil includes a nearly complete skull. Scientists hypothesize that this tyrannosaur was buried either in a river channel or by a flooding event on the floodplain, keeping the skeleton intact.

"The monument is a complex mix of topography -- from high desert to badlands -- and most of the surface area is exposed rock, making it rich grounds for new discoveries, said Titus. "And we're not just finding dinosaurs, but also crocodiles, turtles, mammals, amphibians, fish, invertebrates, and plant fossils -- remains of a unique ecosystem not found anywhere else in the world," said Titus.

Although many tyrannosaur fossils have been found over the last one hundred years in the northern Great Plains region of the northern US and Canada, until relatively recently, little was known about them in the southern US. This discovery, and the resulting research, will continue to cement the monument as a key place for understanding the group's southern history, which appears to have followed a different path than that of their northern counterparts.

This southern tyrannosaur fossil is thought to be a sub-adult individual, 12-15 years old, 17-20 feet long, and with a relatively short head, unlike the typically longer-snouted look of northern tyrannosaurs.

Collecting such fossils from the monument can be unusually challenging. "Many areas are so remote that often we need to have supplies dropped in and the crew hikes in," said Irmis. For this particular field site, Museum and monument crews back-packed in, carrying all of the supplies they needed to excavate the fossil, such as plaster, water and tools to work at the site for several weeks. The crews conducted a three-week excavation in early May 2017, and continued work during the past two weeks until the specimen was ready to be airlifted out.

Irmis said with the help of dedicated volunteers, it took approximately 2,000-3,000 people hours to excavate the site and estimates at least 10,000 hours of work remain to prepare the specimen for research. "Without our volunteer team members, we wouldn't be able to accomplish this work. We absolutely rely on them throughout the entire process," said Irmis.

Irmis says that this new fossil find is extremely significant. Whether it is a new species or an individual of Teratophoneus, the new research will provide important context as to how this animal lived. "We'll look at the size of this new fossil, it's growth pattern, biology, reconstruct muscles to see how the animal moved, how fast could it run, and how it fed with its jaws. The possibilities are endless and exciting," said Irmis.

Read more at Science Daily

DNA Reveals Link Between Saber-Toothed Cats and Domestic Felines

Reconstructed skeleton of a Saber-tooth Cat (Smilodon californicus)

Saber-toothed cats were among the animal kingdom’s most formidable predators. Their sharp, dagger-like teeth could grow up to seven inches long, and were likely used to slay everything from enormous woolly mammoths to rhinos.

Their evolutionary history has been shrouded in mystery, but a new genetic analysis published in the journal Current Biology reveals many surprising finds. One is the link between these stealthy carnivores and animals that are now residing in many households the world over.

“The two saber-toothed cat mitochondrial lineages we investigated — Smilodon and Homotherium — diverged from all living cat-like species around 20 million years ago,” lead author Johanna Paijmans told Seeker, clarifying that the big, ancient cats were indeed related to today’s common domesticated cats.

Paijmans, a researcher at the University of Potsdam’s Institute for Biochemistry and Biology, has always been interested in extinct mammal lineages. When she was asked to perform DNA analysis on saber-tooth cat remains starting about 5 years ago, she jumped at the chance.

The story behind this particular study began long before then, however.

“It all started with the recovery of a 28,000-year-old Homotherium fossil from the North Sea by Jelle Reumer and colleagues in 2000,” Paijmans explained.

Artist depiction of a Homotherium

Homotherium became extinct in Africa about 1.5 million years ago. It was thought to have gone extinct in Europe 300,000 years ago, so scientists were puzzled by the estimated age of the North Sea fossil.

Paijmans, senior author Michael Hofreiter, and their team analyzed this big cat’s complete mitochondrial genome and compared it to that of Smilodon, the world’s best-known saber-toothed cat that became extinct around 10,000 years ago.

“Our results prove that Homotherium did exist in Europe around 28,000 years ago,” Paijmans said.

“With the current knowledge,” she continued, “it’s not clear whether Homotherium did exist (in Europe) between 300,000 and 30,000 years ago at very low population densities, or if Homotherium re-dispersed from North America during the Late Pleistocene after the earlier populations had already gone extinct.”

The date of Homotherium’s presence in Europe opens up yet another intriguing mystery.

“When the first anatomically modern humans migrated to Europe, there may have been a saber-toothed cat waiting for them,” she said.

There is no question that Neanderthals and other early hominids in Europe and Asia lived in regions where saber-toothed cats lurked.

A few years ago, a team of archaeologists working at the Schöningen site in north-central Germany found saber-toothed cat remains next to an ancient stash of weapons. They included several wooden spears, a lance, a double-pointed stick and another stick that was burnt.

It is then possible that early humans waged battles with saber-toothed cats, attempting to either kill or scare them off with torches and their weapons. Since both humans and these predators were drawn to caves, their paths could easily have crossed often, with each group going after similar prey — not to mention each other.

Saber-toothed cats might have even affected early human migration routes, but more evidence is needed to clarify how our human ancestors could have interacted with these fierce felines.

Paijmans said we need to re-think how and where Homotherium lived during the Late Pleistocene, as it occurred in Europe much later than we previously thought. “This,” she said, “can open up new questions about its extinction that can be addressed in future studies.”

In short, it is now possible that anatomically modern humans migrating from Africa could have killed off this species of saber-toothed cat, and possibly others.

A homotherium fossil recovered from the North Sea

Yet another surprising finding from the study is the conclusion that Smilodon and Homotherium were not very closely related.

“In terms of their mitochondrial DNA, these two saber-toothed cats are more distant from each other than tigers are from housecats,” Paijmans said.

After the cats diverged from their common ancestor, they traveled and evolved into distinct forms. Nonetheless, they shared the similar, very toothy dentition that was lost when they went extinct.

Read more at Seeker

Dog Facial Expressions Are Directed at Humans

Brinks the pit bull sits at home smiling at the camera, taken in New York, August 2016.

Few can resist dogs when they raise their inner brows, making their eyes appear to be larger and like those of a human baby who is sad and desiring attention. A study published a few years ago even found that shelter dogs that produced this pathetic facial expression were consistently adopted faster than those that did not.

Dog owners might do well to watch out for this powerful look, because new research suggests that canines tailor their facial expressions for human viewers, and may even intentionally manipulate us with them. 

“There is quite a bit of research showing that human attention affects dog behavior. Our study is one of them,” lead author Juliane Kaminski of the University of Portsmouth told Seeker.

Kaminski, along with colleagues Jennifer Hynds, Paul Morris and senior author Bridget Waller, came to their conclusions after studying 24 beloved family dogs: 13 males and 11 females of various breeds and ages. Before testing started, each dog was allowed to familiarize itself with the human experimenter and the quiet room in which the testing was conducted.

The dogs were next individually brought to the room to a predetermined spot. Each dog was attached to a lead while a female experimenter positioned herself in front of the canine and behaved according to certain conditions. In some instances, she was attentive and holding up food treats that all of the dogs loved. In others, she was attentive, but had no food, or she simply ignored the dog altogether.

As all of these conditions were enacted, a video camera recorded the dogs’ faces. Their facial movements were then analyzed via the Facial Action Coding System (FACS), which was first developed for humans. It identifies observable facial changes associated with underlying muscle movements, permitting an objective, reliable, and standardized measurement of facial movements.

Kaminski and her team found that the dogs produced significantly more facial movements when the experimenter was facing them than when not. Surprisingly, the presence of food had no effect.

Dogs therefore are not only sensitive to a human’s attention when producing facial expressions, but they also appear to be intentionally using these subtle — and sometimes not so subtle — movements to communicate with the viewer.

The findings, published in the journal Scientific Reports, provide evidence that facial expressions of dogs are not always inflexible and involuntary displays reflecting their emotions. Instead, they also often appear to be used for communication, and likely manipulation, too.

“Humans also have the ability to move facial muscles both voluntarily and spontaneously,” Waller said. “So, in some situations we can control our muscles very carefully, and in others, perhaps when we are overcome with emotion, it can be very difficult.”

She added, “In dogs, it is possible that voluntary movement of facial muscles evolved later and in response to selection pressures during domestication.”

Most mammals have a fairly similar set of facial muscles, she explained, but humans and dogs have a particularly complex network of muscles that are capable of producing very slight, as well as very specific, movements. Dogs have some movements that are uncannily similar to those of humans — and their babies.

“But they also have different movements, like ear movements, that humans don’t have,” Waller said. “Other apes, like chimpanzees, also don’t have many ear movements, but numerous monkey species do.”

Mimi the chimpanzee at Chimp Eden in South Africa

The dogs in the study, such as Dusky the basenji and Paul the golden retriever, exhibited an impressive number of expressions. These included pulling their lip corners towards their ears, dropping their jaws, showing their tongues, puckering their lips and much more.

In some cases, the expressions might have been learned from humans. In others, the expressions could hold meanings that are more dog-centric, as for visual cues using additional parts of their body. For example, dogs often lower their front two paws in an unmistakable bow when they want to play.

It could be that dogs use different facial expressions when communicating with other dogs, but the authors are not sure.

“We do not have a lot of research looking at the sensitivity of dogs to other dogs’ attention,” Kaminski said. “We know dogs follow other dogs’ gazes, so they seem to be sensitive to other dogs’ line of sight.”

The researchers suggest it’s possible that horses and goats also attempt to communicate with humans using facial expressions, given that these animals tend to be sensitive to human gazes and levels of attention.

Read more at Seeker

Petals produce a 'blue halo' that helps bees find flowers

Ursinia speciosa is a member of the Daisy family. The region at the base of the petals contains a dark pigment, but appears blue due to the presence of disordered floral nanostructures on the cell surface.

Latest research has found that several common flower species have nanoscale ridges on the surface of their petals that meddle with light when viewed from certain angles.

These nanostructures scatter light particles in the blue to ultraviolet colour spectrum, generating a subtle effect that scientists have christened the 'blue halo'.

By manufacturing artificial surfaces that replicated 'blue halos', scientists were able to test the effect on pollinators, in this case foraging bumblebees. They found that bees can see the blue halo, and use it as a signal to locate flowers more efficiently.

While the ridges and grooves on a petal surface line up next to each other "like a packet of dry spaghetti," when analysing different flower species the researchers discovered these striations vary greatly in height, width and spacing -- yet all produce a similar 'blue halo' effect.

In fact, even on a single petal these light-manipulating structures were found to be surprisingly irregular. This is a phenomenon physicists describe as 'disorder'.

The researchers conclude that these "messy" petal nanostructures likely evolved independently many times across flowering plant species, but reached the same luminous outcome that increases visibility to pollinators -- an example of what's known as 'convergent evolution'.

The study was conducted by a multidisciplinary team of scientists from the University of Cambridge's departments of plant sciences, chemistry and physics along with colleagues from the Royal Botanic Gardens Kew and the Adolphe Merkele Institute in Switzerland.

The findings are published today in the journal Nature.

"We had always assumed that the disorder we saw in our petal surfaces was just an accidental by-product of life -- that flowers couldn't do any better," said senior author Prof Beverley Glover, plant scientist and director of Cambridge's Botanic Garden.

"It came as a real surprise to discover that the disorder itself is what generates the important optical signal that allows bees to find the flowers more effectively."

"As a biologist, I sometimes find myself apologising to physicist colleagues for the disorder in living organisms -- how generally messy their development and body structures can seem."

"However, the disorder we see in petal nanostructures appears to have been harnessed by evolution and ends up aiding floral communication with bees," Glover said.

All flowering plants belong to the 'angiosperm' lineage. Researchers analysed some of the earliest diverging plants from this group, and found no halo-producing petal ridges.

However, they found several examples of halo-producing petals among the two major flower groups (monocots and eudicots) that emerged during the Cretaceous period over 100 million years ago -- coinciding with the early evolution of flower-visiting insects, in particular nectar-sucking bees.

"Our findings suggest the petal ridges that produce 'blue halos' evolved many times across different flower lineages, all converging on this optical signal for pollinators," said Glover.

Species which the team found to have halo-producing petals included Oenothera stricta (a type of Evening Primrose), Ursinia speciosa (a member of the Daisy family) and Hibiscus trionum (known as 'Flower-of-the-hour').

All the analysed flowers revealed significant levels of apparent 'disorder' in the dimensions and spacing of their petal nanostructures.

"The huge variety of petal anatomies, combined with the disordered nanostructures, would suggest that different flowers should have different optical properties," said Dr Silvia Vignolini, from Cambridge's Department of Chemistry, who led the study's physics team.

"However, we observed that all these petal structures produce a similar visual effect in the blue-to-ultraviolet wavelength region of the spectrum -- the blue halo."

Previous studies have shown that many species of bee have an innate preference for colours in the violet-blue range. However, plants do not always have the means to produce blue pigments.

"Many flowers lack the genetic and biochemical capability to manipulate pigment chemistry in the blue to ultraviolet spectrum," said Vignolini. "The presence of these disordered photonic structures on their petals provides an alternative way to produce signals that attract insects."

The researchers artificially recreated 'blue halo' nanostructures and used them as surfaces for artificial flowers. In a "flight arena" in a Cambridge lab, they tested how bumblebees responded to surfaces with and without halos.

Their experiments showed that bees can perceive the difference, finding the surfaces with halos more quickly -- even when both types of surfaces were coloured with the same black or yellow pigment.

Using rewarding sugar solution in one type of artificial flower, and bitter quinine solution in the other, the scientists found that bees could use the blue halo to learn which type of surface had the reward.

"Insect visual systems are different to human ones," explains Edwige Moyroud, from Cambridge's Department of Plant Sciences and the study's lead author. "Unlike us, bees have enhanced photoreceptor activity in the blue-UV parts of the spectrum."

"Humans can identify some blue halos -- those emanating from darkly pigmented flowers. For example the 'black' tulip cultivar, known as 'Queen of the night'."

"However, we can't distinguish between a yellow flower with a blue halo and one without -- but our study found that bumblebees can," she said.

Read more at Science Daily

Scientists dig into the origin of organics on dwarf planet Ceres

SwRI scientists are studying the geology associated with the organic-rich areas on Ceres. Dawn spacecraft data show a region around the Ernutet crater where organic concentrations have been discovered (background image). The color coding shows the surface concentration of organics, as inferred from the visible and near infrared spectrometer. The inset shows a higher resolution enhanced color image of the Ernutet crater acquired by Dawn’s framing camera. Regions in red indicate higher concentration of organics.

Since NASA's Dawn spacecraft detected localized organic-rich material on Ceres, Southwest Research Institute (SwRI) has been digging into the data to explore different scenarios for its origin. After considering the viability of comet or asteroid delivery, the preponderance of evidence suggests the organics are most likely native to Ceres.

"The discovery of a locally high concentration of organics close to the Ernutet crater poses an interesting conundrum," said Dr. Simone Marchi, a principal scientist at SwRI. He is discussing his team findings today at a press conference at the American Astronomical Society's 49th Division for Planetary Sciences Meeting in Provo. "Was the organic material delivered to Ceres after its formation? Or was it synthesized and/or concentrated in a specific location on Ceres via internal processes? Both scenarios have shortfalls, so we may be missing a critical piece of the puzzle."

Ceres is believed to have originated about 4.5 billion years ago at the dawn of our solar system. Studying its organics can help explain the origin, evolution, and distribution of organic species across the solar system. The very location of Ceres at the boundary between the inner and outer solar system and its intriguing composition characterized by clays, sodium- and ammonium-carbonates, suggest a very complex chemical evolution. The role of organics in this evolution is not fully understood, but has important astrobiological implications.

"Earlier research that focused on the geology of the organic-rich region on Ceres were inconclusive about their origin," Marchi said. "Recently, we more fully investigated the viability of organics arriving via an asteroid or comet impact."

Scientists explored a range of impact parameters, such as impactor sizes and velocities, using iSALE shock physics code simulations. These models indicated that comet-like projectiles with relatively high impact velocities would lose almost all of their organics due to shock compression. Impacting asteroids, with lower incident velocities, can retain between 20 and 30 percent of their pre-impact organic material during delivery, especially for small impactors at oblique impact angles. However, the localized spatial distribution of organics on Ceres seems difficult to reconcile with delivery from small main belt asteroids.

"These findings indicate that the organics are likely to be native to Ceres," Marchi said.

From Science Daily

Ancient preen oil: Researchers discover 48-million-year-old lipids in a fossil bird

48-million-year old bird fossil excavated at the “Messel Pit“ in Germany. Markings show the uropygial gland.

As a rule, soft parts do not withstand the ravages of time; hence, the majority of vertebrate fossils consist only of bones. Under these circumstances, a new discovery from the UNESCO World Heritage Site "Messel Pit" near Darmstadt in Germany comes as an even bigger surprise: a 48-million-year old skin gland from a bird, containing lipids of the same age. The oldest lipids ever recorded in a fossil vertebrate were used by the bird to preen its plumage. The study is now published in the scientific journal Royal Society Proceedings B.

Birds spend a large amount of time preening their plumage. This makes sense, since the set of feathers adds to each bird's particular appearance, isolates and enables them to fly. In this preening ritual, the uropygial gland, located at the lower end of the bird's back, plays an important role. It produces an oily secretion used by the birds to grease their plumage in order to render it smoother and water-repellent.

Together with a group of international colleagues, Dr. Gerald Mayr, head of the Ornithology Section at the Senckenberg Research Institute, now discovered the oldest occurrence of such preen oils in birds known to date. With an age of 48 million years, this ancient preen oil constitutes a small scientific sensation. "The discovery is one of the most astonishing examples of soft part preservation in animals. It is extremely rare for something like this to be preserved for such a long time," says Mayr.

The organic materials that the soft parts consist of usually decompose within decades, or even just a few years. Several-million-year-old feathers and fur remnants are only known from a small number of fossil sites to date, including the oxygen-poor oil shale deposits of the Messel fossil site. This site also yielded the uropygial gland and the contained lipids examined in the course of this study.

"As shown by our detailed chemical analysis, the lipids have kept their original chemical composition, at least in part, over a span of 48 million years. The long-chain hydrocarbon compounds from the fossil remains of the uropygial gland can clearly be differentiated from the oil shale surrounding the fossil," explains Mayr. The analysis offers proof that the fossil artifact constitutes one of the oldest preserved uropygial glands -- a suspicion which had already been suggested by the arrangement at the fossil bird skeleton, albeit not finally confirmed.

To date, it is not clear why the lipids from the uropygial gland were able to survive for so long. It is possible that hey hardened into nore decomposition-resistant waxes under exclusion of oxygen. In addition, the researchers assume that one of the properties of the preen oil played a role that is still shown by modern birds today -- its antibacterial components. They may have been the reason that after the bird's death only few bacteria were able to settle in, preventing the full-on decomposition.

Read more at Science Daily

Filling the early universe with knots can explain why the world is three-dimensional

This is a computer graphic showing the kind of tight network of flux tubes that the physicists propose may have filled the early universe.

The next time you come across a knotted jumble of rope or wire or yarn, ponder this: The natural tendency for things to tangle may help explain the three-dimensional nature of the universe and how it formed.

An international team of physicists has developed an out-of-the-box theory which proposes that shortly after it popped into existence 13.8 billion years ago the universe was filled with knots formed from flexible strands of energy called flux tubes that link elementary particles together. The idea provides a neat explanation for why we inhabit a three-dimensional world and is described in a paper titled "Knotty inflation and the dimensionality of space time" accepted for publication in the European Physical Journal C.

"Although the question of why our universe has exactly three (large) spatial dimensions is one of the most profound puzzles in cosmology ... it is actually only occasionally addressed in the [scientific] literature," the article begins.

For a new solution to this puzzle, the five co-authors -- physics professors Arjun Berera at the University of Edinburgh, Roman Buniy at Chapman University, Heinrich Päs (author of The Perfect Wave: With Neutrinos at the Boundary of Space and Time) at the University of Dortmund, João Rosa at the University of Aveiro and Thomas Kephart at Vanderbilt University -- took a common element from the standard model of particle physics and mixed it with a little basic knot theory to produce a novel scenario that not only can explain the predominance of three dimensions but also provides a natural power source for the inflationary growth spurt that most cosmologists believe the universe went through microseconds after it burst into existence.

The common element that the physicists borrowed is the "flux tube" composed of quarks, the elementary particles that make up protons and neutrons, held together by another type of elementary particle called a gluon that "glues" quarks together. Gluons link positive quarks to matching negative antiquarks with flexible strands of energy called flux tubes. As the linked particles are pulled apart, the flux tube gets longer until it reaches a point where it breaks. When it does, it releases enough energy to form a second quark-antiquark pair that splits up and binds with the original particles, producing two pairs of bound particles. (The process is similar to cutting a bar magnet in half to get two smaller magnets, both with north and south poles.)

"We've taken the well-known phenomenon of the flux tube and kicked it up to a higher energy level," said Kephart, professor of physics at Vanderbilt.

The physicists have been working out the details of their new theory since 2012, when they attended a workshop that Kephart organized at the Isaac Newton Institute in Cambridge, England. Berera, Buniy and Päs all knew Kephart because they were employed as post-doctoral fellows at Vanderbilt before getting faculty appointments. In discussions at the workshop, the group became intrigued by the possibility that flux tubes could have played a key role in the initial formation of the universe.

According to current theories, when the universe was created it was initially filled with a superheated primordial soup called quark-gluon plasma. This consisted of a mixture of quarks and gluons. (In 2005 the quark-gluon plasma was successfully recreated in a particle accelerator, the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, by an international group of physicists, including three from Vanderbilt: Stevenson Chair in Physics Victoria Greene and Professors of Physics Charles Maguire and Julia Velkovska.)

Kephart and his collaborators realized that a higher energy version of the quark-gluon plasma would have been an ideal environment for flux tube formation in the very early universe. The large numbers of pairs of quarks and antiquarks being spontaneously created and annihilated would create myriads of flux tubes.

Normally, the flux tube that links a quark and antiquark disappears when the two particles come into contact and self-annihilate, but there are exceptions.

If a tube takes the form of a knot, for example, then it becomes stable and can outlive the particles that created it. If one of particles traces the path of an overhand knot, for instance, then its flux tube will form a trefoil knot. As a result, the knotted tube will continue to exist, even after the particles that it links annihilate each other. Stable flux tubes are also created when two or more flux tubes become interlinked. The simplest example is the Hopf link, which consists of two interlinked circles.

In this fashion, the entire universe could have filled up with a tight network of flux tubes, the authors envisioned. Then, when they calculated how much energy such a network might contain, they were pleasantly surprised to discover that it was enough to power an early period of cosmic inflation.

Since the idea of cosmic inflation was introduced in the early 1980s, cosmologists have generally accepted the proposition that the early universe went through a period when it expanded from the size of a proton to the size of a grapefruit in less than a trillionth of a second.

This period of hyper-expansion solves two important problems in cosmology. It can explain observations that space is both flatter and smoother than astrophysicists think it should be. Despite these advantages, acceptance of the theory has been hindered because an appropriate energy source has not been identified.

"Not only does our flux tube network provide the energy needed to drive inflation, it also explains why it stopped so abruptly," said Kephart. "As the universe began expanding, the flux-tube network began decaying and eventually broke apart, eliminating the energy source that was powering the expansion."

When the network broke down, it filled the universe with a gas of subatomic particles and radiation, allowing the evolution of the universe to continue along the lines that have previously been determined.

The most distinctive characteristic of their theory is that it provides a natural explanation for a three-dimensional world. There are a number of higher dimensional theories, such as string theory, that visualize the universe as having nine or ten spatial dimensions. Generally, their proponents explain that these higher dimensions are hidden from view in one fashion or another.

The flux-tube theory's explanation comes from basic knot theory. "It was Heinrich Päs who knew that knots only form in three dimensions and wanted to use this fact to explain why we live in three dimensions," said Kephart.

A two-dimensional example helps explain. Say you put a dot in the center of a circle on a sheet of paper. There is no way to free the circle from the dot while staying on the sheet. But if you add a third dimension, you can lift the circle above the dot and move it to one side until the dot is no longer inside the circle before lowering it back down. Something similar happens to three-dimensional knots if you add a fourth dimension -- mathematicians have shown that they unravel. "For this reason, knotted or linked tubes can't form in higher-dimension spaces," said Kephart.

The net result is that inflation would have been limited to three dimensions. Additional dimensions, if they exist, would remain infinitesimal in size, far too small for us to perceive.

Read more at Science Daily

A Black Butterfly’s Wings Point the Way Toward Better Solar Cells

Black butterfly

A microscopic pattern on the wings of a butterfly has shown scientists how to capture more of the sun’s energy in solar cells.

The scales of the black-colored common rose butterfly are topped with an irregular lattice of chitin and melanin. Those structures drew the attention of Radwan Siddique, an engineer trying to develop a technique for building 3D nanostructures as part of his doctoral work at Germany’s Karlsruhe Institute of Technology.

Siddique told Seeker he came across a description of the butterfly’s wings in the course of his research. The lattice helps the cold-blooded insect regulate its body temperature, keeping it warm enough to fly in cool weather, he said.

“I was so intrigued that I literally went to a lot of butterfly nurseries and gathered several butterflies,” said Siddique, now a post-doctoral researcher at Caltech. “The black butterfly was one of them. I was putting them under SEM [an electron microscope] and looking at the structures.” It openings are less than a millionth of a meter wide, but they scatter light and help the butterfly absorb more of the sun’s heat.

“They use those nanostructures to improve absorption,” he said. “So I asked, ‘Can we use the same nanostructres in this type of solar cell, which is not highly used because the absorption isn’t that good?’”

Scientists from KIT and Caltech utilize the disordered nanoholes of the black butterfly to improve solar cell performance.

By mimicking the butterfly’s structure in a sheet of hydrogenated amorphous silicon, he and his colleagues at Karlsruhe were able to capture more low-frequency light — at wavelengths near the infrared end of the spectrum — that wouldn’t have been converted to energy otherwise. A layer of polymer pockmarked with circular indentations of various sizes, transferred to a silicon base, was able to pick up about double the amount of energy that a smooth surface produced and convert it to electricity. Angling those indentations might improve those efficiencies even more, he said.

The findings were published Oct. 18 in the research journal Science Advances. They’re part of a growing body of research aimed at improving the efficiency and reducing the size of solar cells.

Scanning electron microscope image of bio-inspired nanoholes

The ability to produce solar power with a thin film, as opposed to the larger, more typical crystal-based cells, holds the promise of making them more useful. They could be used to power personal electronics or for larger-scale applications, such as being incorporated into windows or other building materials.

And Siddique and his colleagues aren’t the first to find inspiration in the natural world: Earlier this year, researchers in Australia etched a fractal pattern inspired by the leaves of a fern onto sheets of graphene to increase the surface area available for storing and conducting energy.

Read more at Seeker

Archaeologists Unearth Roman Structure at the Foot of Jerusalem’s Western Wall

Reporters visit the recently discovered ancient roman theatre from the second sanctuary that was found by the Israeli Antiquity Authority at the foot of the Western Wall tunnels in Jerusalem's Old City on October 16, 2017. Excavations conducted by the Israel Antiquities Authority have uncovered large portions of the Western Wall that have been hidden for 1,700 years.

Israeli archaeologists in Jerusalem's Old City on Monday unveiled a newly unearthed section of the Western Wall and the first Roman public structure ever discovered in the city, they said.

Archaeologist Joe Uziel said he and his colleagues knew the wall section was there and had expected to find a Roman street at its base.

"But as we excavated and excavated we realized we weren't getting to the street. Instead we have this circular building," he told reporters at the underground site.

"Basically we realized that we were excavating a theatre-like (Roman) structure."

He said that carbon-14 and other dating methods indicated it came from the second or third centuries AD and appeared to be unfinished.

The Israel Antiquities Authority (IAA), which conducted the two-year dig, said that historical sources mentioned such structures but in 150 years of modern archaeological research in the city none had been found.

The section of the 2,000-year-old Western Wall uncovered by the diggers is about 15 meters (yards) in width and eight meters high, with the stones very well preserved.

It had been buried under eight meters of earth for 1,700 years, the IAA said.

The Western Wall is among the last remnants of the retaining structures that surrounded the second Jewish temple until its destruction by the Romans in 70 AD.

It is the holiest site where Jews are permitted to pray.

Previously, the last section to be exposed was in 2007, IAA chief Jerusalem architect Yuval Baruch said.

"Exposing parts of the Western Wall is of course extremely, extremely, extremely exciting, but the structure we are looking at right now we had no idea would be here," Uziel said, pointing to the 200-seat auditorium.

"It's probably the most important archaeological site in the country, the first public structure from the Roman period of Jerusalem," Baruch said.

"We know a lot about dwelling houses, a lot about installations, water systems, roads, streets, but this is the first time we can present to the public a Roman public structure," he added.

Religious tensions

The IAA statement said the building could have been a meeting chamber for Roman administrative officials or a concert venue, but said its location under an ancient arch, which could have served as its roof, gave a clue.


"This is a relatively small structure compared to known Roman theatres," it said.

"This fact, in addition to its location under a roofed space — in this case under Wilson’s Arch — leads us to suggest that this is a theatre-like structure of the type known in the Roman world as an odeon."

"In most cases, such structures were used for acoustic performances. Alternatively, this may have been a structure known as a bouleuterion — the building where the city council met," it said.

Wilson's Arch, named for 19th-century explorer and surveyor Charles Wilson, dates to the second temple period and served as a passageway for people entering the temple compound, the IAA says.

Uziel said that the archaeologists worked with care, mindful of the Jewish, Muslim, and Christian worshippers nearby.

"We did not want to disturb any of the religious activities that were occurring in this area," he said.

Read more at Seeker

Planet Nine May Be the Best Explanation for ‘Weirdness’ of Kuiper Belt Objects

Artist depiction of Planet Nine

Planet Nine is out there, and astronomers are determined to find it, according to a new statement from NASA. In fact, mounting evidence suggests it's hard to imagine our solar system without the unseen world.

The hypothetical planet is believed to be about 10 times more massive than Earth and located in the dark, outer reaches of the solar system, approximately 20 times farther from the sun than Neptune is. While the mysterious world still has yet to be found, astronomers have discovered a number of strange features of our solar system that are best explained by the presence of a ninth planet, according to the NASA statement.

"There are now five different lines of observational evidence pointing to the existence of Planet Nine," Konstantin Batygin, a planetary astrophysicist at the California Institute of Technology (Caltech) in Pasadena, said in the statement. "If you were to remove this explanation and imagine Planet Nine does not exist, then you generate more problems than you solve. All of a sudden, you have five different puzzles, and you must come up with five different theories to explain them."

In 2016, Batygin and co-author Mike Brown, an astronomer at Caltech, published a study that examined the elliptical orbits of six known objects in the Kuiper Belt, a distant region of icy bodies stretching from Neptune outward toward interstellar space. Their findings revealed that all of those Kuiper Belt objects have elliptical orbits that point in the same direction and are tilted about 30 degrees "downward" compared to the plane in which the eight official planets circle the sun, according to the statement.

Using computer simulations of the solar system with a Planet Nine, Batygin, and Brown also showed that there should be even more objects tilted a whopping 90 degrees with respect to the solar plane. Further investigation revealed that five such objects were already known to fit these parameters, the researchers said.

Since then, the astronomers have found new evidence that further supports the existence of Planet Nine. With help from Elizabeth Bailey, an astrophysicist and planetary scientist at Caltech, the team showed that Planet Nine's influence might have tilted the planets of our solar system, which would explain why the zone in which the eight major planets orbit the sun is tilted by about 6 degrees compared to the sun's equator.

"Over long periods of time, Planet Nine will make the entire solar-system plane precess, or wobble, just like a top on a table," Batygin said in the statement.

Finally, the researchers demonstrate how Planet Nine's presence could explain why some Kuiper Belt objects orbit in the opposite direction from everything else in the solar system.

"No other model can explain the weirdness of these high-inclination orbits," Batygin said in the statement. "It turns out that Planet Nine provides a natural avenue for their generation. These things have been twisted out of the solar system plane with help from Planet Nine and then scattered inward by Neptune."

Read more at Seeker

A Cheaper, Faster Way for Growing Human Brain Cells

Pipetting samples into a petri dish used in DNA, stem cell, biomedical, biotechnology, and pharmacological research

One of the fastest and most effective ways to find new treatments for diseases like cancer is a technique called high-throughput screening. You start with a large sample of identical cancer cells with the same genetic mutation. Then, using fast-moving robotic arms, you divvy up the cells on big plastic trays with thousands of individual indentations, or wells. The same precision robotic arms then treat each separate well with a different compound or drug.

After a few days or weeks, you test each well to see which compounds are the most promising for further testing. If you tried to repeat the same massive screening process with pipette-wielding lab workers, it might take years to complete.

Alzheimer’s researchers want to use the same high-throughput screening technique to test thousands of potentially life-saving compounds on brain cells. For that to work, though, they first need to find a reliably homogeneous supply of identical brain cells to run through the screening process.

But unlike human cancer cells, which are easily cloned and grown in the lab, human brain cells don’t survive in a dish. Instead, researchers have attempted to grow their own brain cells from induced pluripotent stem cells, which are skin or blood cells that have been reprogramed to become undifferentiated, blank-slate stem cells.

That’s easier said than done, though.

To grow a brain cell from a stem cell, you need to mimic the natural biological differentiation process that results in a specific type of brain cell. That requires a cocktail of precisely-timed doses of chemicals called growth factors that activate and deactivate different genes in the growing cell.

The trouble with most lab-grown brain cells is they’re highly heterogeneous by nature, meaning that different subtypes of neurons and glia — a “helper” cell in the central nervous system — emerge from the same differentiation process and then need to be sorted out. This multi-step process is expensive and time-consuming, especially for researchers who want to generate millions of identical brain cells for high-throughput screening.

The good news is a far cheaper and much faster system may be on the way. A team of Alzheimer’s researchers from the Gladstone Institutes has developed a simple, two-step process for growing thousands of identical neurons from a single stem cell, according to a paper published in the journal Stem Cell Reports.

Li Gan is associate director and senior investigator at the Gladstone Institute of Neurological Disease and a professor of neurology at the University of California, San Francisco.

Like many recent breakthroughs in biotech, Gan told Seeker, this one started with gene-editing. Using a CRISPR-like genome-editor called TALEN, the Gladstone researchers programed their stem cells to overexpress a certain gene that’s responsible for differentiating cells into neurons. But the gene would only be activated when the stem cell was exposed to a common antibiotic called doxycycline.

The gene-editing program itself wasn’t new, Gan explained, but had previously been installed in stem cells by viruses, which led to unpredictable results. Some stem cells would take up more of the virus than others, ultimately resulting in a mix of neurons and glia, not a pure sample of neurons. With TALEN, Gan and her team could precision edit one stem cell and clone it as many times as they wanted — creating “tens of millions” of identically pre-programed stem cells.

After just three days of exposure to doxycycline, the stem cells transformed into precursor neurons. And not just any old neuron, but a specific subtype of neuron that’s of particular interest to Alzheimer’s researchers. Most importantly, every single precursor neuron was exactly the same.

“The key to our system is that we allow our cells to be completely synchronized,” said Gan. “They turn into the same type of neurons at exactly the same time, because they express this particular gene exactly the same.”

When the cells were removed from the doxycycline solution, the gene immediately turned off, ensuring that none of the cells continued to differentiate into another neuron subtype or glia cell. The second step in the two-step process was to culture the cells for four weeks until they developed into functionally active neurons.

The reason Gan and her team chose this particular neuron subtype was that it contained tau, the naturally occurring brain protein that can form tangles that choke off and kill brain cells in Alzheimer’s and other neurodegenerative diseases. Abnormally high levels of tau are strongly associated with Alzheimer’s and other forms of dementia, and previous studies had shown that lowering tau levels in mice with Alzheimer’s can recover some memory deficits.

If the Gladstone team could find a new compound that lowers tau levels in human brain cells, it would be an excellent proof of concept that the high-throughput screening system worked.

Robotic arms quickly filled each of the 394 wells on a large plastic tray with 2,000 of Gan’s engineered neurons. To test the broadest sample of treatments possible, the Gladstone team ran the screening against 1,280 different bioactive molecules contained in the Library of Pharmaceutically Active Compounds. The top two tau-lowering candidates were both from the same family of compounds known as AR agonists.

Read more at Seeker