Nov 23, 2013

Biodiversity Higher in the Tropics, but Species More Likely to Arise at Higher Latitudes

A new study of 2300 species of mammals and nearly 6700 species of birds from across the globe helps explain why there are so many more species of plants and animals in the tropics than at higher latitudes. In a study supported by the National Evolutionary Synthesis Center in North Carolina, researchers found that while the tropics harbor a greater diversity of species, the number of subspecies -- potential stepping stones in the process by which one species becomes two -- is actually greater in the harsher environments typical of higher latitudes.

The surprising results suggest that the latitudinal diversity gradient may be due higher species turnover -- a higher potential for speciation counterbalanced by a higher potential for extinction -- towards the poles than near the equator, the researchers say.

Scientists have known for more than a century that species diversity increases towards the equator. Think tropical rainforests -- which house two thirds of the world's species -- teeming with buzzing insects, screeching birds and howling monkeys, versus the frigid tundra, where life is largely limited to scattered trees and only a few dozen kinds of mammals, such as caribou and foxes.

Numerous hypotheses have been proposed to explain this pattern. One idea is that tropical regions harbor greater biodiversity because they are especially fertile grounds for the formation of new species -- i.e., "cradles of diversity." Another idea is that biodiversity hotspots are less likely to lose the species they already have.

"There's a lot of controversy over what explains the global pattern of biodiversity," said lead author Carlos Botero of North Carolina State University.

In a study to appear in the November 22 issue of Molecular Ecology, Botero and colleagues assembled a data set of climate and weather patterns across the globe, and combined it with genetic data other information for nearly 50% and 70% of all mammals and birds known to be alive today.

The team was surprised to find that while the number of bird and mammal species increases closer to the equator, the number of genetically distinct groups within each species -- known as subspecies -- is greater in the harsher environments typical of higher latitudes.

"These are environments that are colder and drier, and where the differences between the hottest and coolest months are more extreme," Botero explained.

Animals in these environments are more likely to freeze during cold winters or die during usually hot summers. "If extreme weather events wipe out a population every now and then, but don't wipe out an entire species, the populations that survive will be geographically separated and could start to diverge from one another," Botero said.

The results are consistent with a 2007 study by researchers at the University of British Columbia suggesting that -- contrary to conventional wisdom -- species arise faster in temperate zones than in the tropics. "It may be that species come and go more frequently in the temperate zones," Botero said.

Read more at Science Daily

Artificial Skin Created Using Stem Cells from the Umbilical Cord

An important scientific breakthrough, developed by the University of Granada, will aid the immediate use of artificially-grown skin for major burn patients, since the skin could be stored in tissue banks and made available when needed.

One of the problems major burn victims have is that, using the current protocols for artificial skin, they need to wait various weeks in order for it to be grown, using healthy skin from the own patient.

Spanish scientists, from the Tissue Engineering Research Group, from the Dept. of Histology at the University of Granada, have managed, for the first time, to grow artificial skin from stem cells derived from the umbilical cord. Their study, published in the journal Stem Cells Translational Medicine, shows the ability of Wharton jelly mesenschymal stem cells to turn to oral-mucosa or skin-regeneration epithelia.

To grow the artificial skin, the researchers have used, in addition this new type of epithelia covering, a biomaterial made of fibrin and agarose, already designed and developed by the University of Granada research team. The work has been carried out in the laboratories of the Faculty of Medicine, alongside the Experimental Unit of the Granada “Virgen de las Nieves” University Hospital Complex.

Prior studies from this same research team, which received recognition in the World Congress on Tissue Engineering, held a few months ago in Seoul (S. Korea), already pointed to the possibility that Wharton stem cells could be turned into epithelia cells. This current work is the confirmation of those initial studies and its application to two regeneration structures: skin and oral mucosa, increasingly needed in injuries in these parts of the body.

Instant Use

One of the problems major-burn victims currently have is that, in order to apply the current techniques of artificial skin, a number of weeks are needed. That is because the skin needs to be grown from parts of the patient’s healthy skin. “Creating this new type of skin using stem cells, which can be stored in tissue banks, means that it can be used instantly when injuries are caused, and which would bring the application of artificial skin forward many weeks”, as explained by Antonio Campos, Professor of Histology at the University of Granada and one of the authors of this study.

Read more at Science Daily

Nov 22, 2013

Adopt a Skull and Save a Collection That Helped Debunk Phrenology

The Mütter Museum in Philadelphia wants you to adopt a skull. Among their strange and fascinating collection of medical artifacts and anatomical specimens is a collection of 139 skulls collected in the 1800s by Viennese anatomist Joseph Hyrtl, who was trying to debunk the then-popular pseudoscience of phrenology.

Your $200 donation pays for the initial restoration and remounting of a skull of your choosing, and gets your name on a small plaque next to your adopted skull for the next year.

The catalog of the skulls hints at many interesting stories. Some specimens have already been adopted, including the skulls of a Viennese prostitute, a notorious Thai criminal, and a tightrope walker who broke his neck (adopted by the editors of a blog called Skull-A-Day). The same goes for Geza Uirmeny of Hungary (or possibly Romania), who attempted suicide at age 70 by cutting his throat, but remarkably survived, and perhaps even more remarkably “lived until 80 without melancholy.”

And, alas, there’s Andrejew Sokoloff, who belonged to a Russian sect that practiced castration as a safeguard against ungodly lust. Sokoloff “died of self-inflicted removal of testicles,” according to museum records, but his skull will be well cared for thanks to the generosity of Judy and George Wohlreich.

There are roughly 100 skulls still awaiting adoption, says museum curator Anna Dhody. They include sailors, soldiers, robbers, and Gypsies. Anton Mikschik, a 17-year-old Moravian shoemaker’s apprentice, killed himself after getting caught stealing. Maria Falkensteiner, a Tyrolean maidservant, was just 22 when she died of meningitis. Joska Soltesz, a Hungarian reformist and soldier, died of pneumonia at 28.

The skulls have been in the museum’s collection since 1874. They include only 14 women, but represent a wide range of ages, from 8 to 80. Many died in poorhouses or jails, or from suicide or execution, which probably made it easier for Hyrtl’s associates to obtain the remains without facing resistance from surviving relatives. Such practices would be completely unacceptable today, but for 19th century anatomists it was standard procedure. In at least one case Hyrtl apparently employed the services of a grave robber.

Hyrtl taught anatomy at the University of Vienna, and he was a consummate collector. His personal collection may have once included the skull of Mozart. In addition to human skulls, he possessed 800 fish skeletons and more than 300 “organs of hearing” from a variety of animals.

Hyrtl lived during the heyday of phrenology, the idea that the brain was made up of discrete mental organs, each with a specific function. The size of each organ in a given person was thought to indicate the strength of the corresponding mental faculty. These ranged from things like benevolence and cautiousness to the propensity to bear lots of offspring. Because the skull remains soft during infancy, the thinking went, its external bumps reflected the size of the mental organs underneath — and, by proxy, the character of the person.

“Phrenology was an accepted science, and what went hand in hand with that at the time was the assumption that the Caucasian race was the most superior race,” Dhody said.

It’s all bunk, of course. Today that’s obvious. Hyrtl didn’t buy it either, but his reasons weren’t entirely scientific. A devout Catholic, he believed that the mind and brain developed according to God’s plan and therefore had no relationship to any measurements of the skull, which like any part of the body would be subject to forces in the natural world. He set out to prove this by collecting skulls.

He hoped to show — and did — that there was as much variation in cranial anatomy within the European Caucasian population as there was between different racial groups. His findings undermined the racist suppositions of the phrenologists.

Although he was already famous in academic circles, Hyrtl did not make a lot of friends with this line of inquiry and seems to have been forced into early retirement from the university as a result, Dhody says. “He definitely made waves.” By the end of his life he found himself in financial trouble, and began selling off collections. The Mütter bought the skulls and an assortment of other anatomical specimens from Hyrtl in 1874 for 6,410 Austrian thalers, or about $4,800 at the time.

Read more at Wired Science

This Parasite Eats a Fish’s Tongue — And Takes Its Place

Stop me if you’ve heard this one before. A fish walks into a bar and takes a seat. The bartender asks what he wants to drink, but the fish doesn’t say anything. So the bartender asks, “What, cat got your tongue?” The fish grabs a cocktail napkin and writes out, No, actually, it was an isopod. An isopod got my tongue and by “got” I mean she ate it.

That joke may not be funny to you, but it’s hilarious to the tongue-eating isopod. You see, in the Gulf of California there actually exists a critter, Cymothoa exigua, that targets a fish by infiltrating its gills and latching onto its tongue. It proceeds to not only consume the organ, but will then replace it with its own body, providing the fish with a new fully functioning tongue it uses (probably a bit begrudgingly) to grind food against tiny teeth on the roof of its mouth.

This remarkable attack is the only known instance in the animal kingdom of a parasite functionally replacing an organ of its host. And while C. exigua targets several other fish, attaching to their tongues and draining their blood, only with the rose snapper does it devour and completely replace the organ as an operating structure, according to marine biologist Rick Brusca of the University of Arizona. And he stresses that while there are hundreds of such species of tongue-targeting isopods, contrary to many media reports, only C. exigua can actually truly assume the duties of the organ.

If you can believe it, this is a love story at heart. And the rose snapper’s face is the stage on which it unfolds.

These isopods are protandrous hermaphrodites: They first mature into males, but then switch sexes to become females. The magic starts when more than one C. exigua lands in a given fish’s gills. When the first one infiltrates it begins to mature into a male, but when the second one appears, said Brusca, it “stimulates the first one to change sex and become a female and crawl from the gills up through the throat and attach to the tongue, and then this new second one is the male that will impregnate her.”

The female next anchors herself to the tongue with seven pairs of legs, each tipped with a highly muscularized spine that looks a bit like a scorpion’s stinger. It is here where she’ll mate and spend the rest of her life experiencing the world as the snapper does, only, you know, without the excruciating pain.

As she grows, she molts just like any other arthropod and feeds on the snapper’s tongue not by gnawing away, but by sucking the blood out of it. “They have five sets of jaws,” said Brusca, “and all five of them are modified into these stiletto-like devices, and a couple of them are like long lances, if you will, that slice open the tissue of the host fish. And then the others operate together kind of like a soda straw to draw the blood up out of the wound that they’ve created.”

In this way C. exigua will slowly drain the life out of the snapper’s tongue, which atrophies from the tip on back, bit by bit, until nothing but the muscular stub remains. This the isopod now grasps with her rearmost three or four pairs of legs, essentially becoming the fish’s new tongue. And the isopod has likely evolved like this to keep her host alive, according to Brusca, allowing her more time to rear her young.

But once the tongue is gone, the female is left without a food supply. So as her young continue to develop, she lives solely on stored energy supplies, according to Brusca. Scientists aren’t yet sure at what point the young are released, or how exactly they find fish of their own, but Brusca reckons that the female may wait until her host is schooling with other fish to cut her offspring loose from the brood pouch, giving the young plenty of targets.

What happens next is like that scene in Titanic where the band goes down with the ship, except that those guys probably hadn’t been randomly switching sexes and eating fish tongues. With her procreation complete, the female isopod, who lost her ability to swim as she matured, “probably lets go and leaves or gets swallowed, but she’s out of the picture,” said Brusca. “And now you’ve got a fish with no tongue, so it’s not going to survive either. So it’s really a case of true parasitism. In fact, the fish ends up getting sacrificed for the sake of the isopod.”

It’s still not known quite why C. exigua goes so far in its parasitism of rose snappers, where in other species it merely sips from the tongue — not destroying it and taking over its job. “Maybe the tongue in the rose snapper is particularly susceptible,” said Brusca. “Maybe it doesn’t have as good a vascularization as other fish tongues.”

There’s still much to be learned here, but the advantages of such a lifestyle are clear: The female isopod not only gets a steady meal, but also a perfectly safe bunker in which to raise her young. Like any other creature, her purpose is to pass along her genes. And with her mission accomplished, she goes down with the ship.

Read more at Wired Science

'Man-Eating Monster Dino' Made Way for T. Rex

A newly discovered predatory dinosaur from Utah is so large that it may represent the biggest species of meat-eating dino that ever lived in North America.

The dinosaur, Siats meekerorum a.k.a. "Man Eating Monster," is described in the latest issue of Nature Communications. The specimen was just a juvenile, but conservatively it measured at least 30 feet long and weighed 9,000 pounds.

The name Siats pays homage to a human-chomping monster from legends of the Ute native tribe of Utah.

"Siats still had a lot of room to grow, and there is only a 4-inch difference between the estimated femur length of a juvenile Siats and an adult Acrocanthosaurus (the second largest predator in North America), so we think a safe estimate for an adult Siats is that it at least vied with Acrocanthosaurus (11,000 pounds) for the No. 2 slot," lead author Lindsay Zanno told Discovery News.

"However, our upper estimate on Siats is a body mass larger than T. rex (currently in the No. 1 spot), so future material may reveal Siats grew up to be one of the biggest predators known around the globe," added Zanno, who is director of the Paleontology and Geology Research Laboratory at the North Carolina Museum of Natural Sciences.

Zanno, who is also an assistant professor of biology at North Carolina State University, co-authored the paper with Peter Makovicky of the Field Museum of Natural History.

The researchers analyzed the remains for Siats, which were unearthed at the Dakota Formation in Emery County, Utah. The fossils reveal that the huge dinosaur lived approximately 98 million years ago at the dawn of the Late Cretaceous.

It was a carcharodontosaur, which refers to a type of enormous carnivorous dinosaur known, not just for their size, but also for their jagged, sharp teeth.

Zanno and Makovicky believe that the mere existence of these apex predators prevented tyrannosaurs at the time from evolving into even larger beasts. It was only when Siats and other carcharodontosaurs mysteriously died out that tyrannosaurs like T. rex emerged.

"In the rock beds that contain the colossal bones of Siats we also find the teeth of relatively tiny tyrannosaurs about the size of a large dog," Zanno said. "This is a clear indication that tyrannosaurs were living in the shadows and carcharodontosaurs like Siats reigned at the dawn of the Late Cretaceous in North America."

She thinks it's possible that Siats even ate these small tyrannosaurs, although it probably went after less aggressive prey, such as large, plant-eating long-necked dinosaurs and primitive duckbilled dinos.

These and other animals, including crocodiles, turtles and mammals, all lived in a lush, wet coastal plain environment not far from a shallow sea that was then spreading over central North America. The sea divided the continent into smaller island landmasses.

Roger Benson, a paleobiologist at the University of Oxford, told Discovery News that the finding of Siats shows that extremely large predatory dinosaurs were present in North America at the time and that “their presence would have excluded tyrannosaurs from evolving to multi-ton sizes.”

Read more at Discovery News

Israeli Wine Cellar Predates the Bible

One of the world’s oldest and largest wine cellars has just been unearthed in Israel, according to a presentation today at the annual meeting of the American Schools of Oriental Research in Baltimore.

The cellar dates to approximately 1700 B.C., and was found at a site called Tel Kabri within the ruins of a northern Canaanite city. Its age predates both the Bible and the Dead Sea Scrolls by hundreds of years.

The researchers christened a three-foot-long jar in the cellar “Bessie.”

“We dug and dug, and all of a sudden, Bessie’s friends started appearing — five, 10, 15, ultimately 40 jars packed in a 15-by-25-foot storage room,” Eric Cline, chair of George Washington University’s Department of Classical and Near Eastern Languages and Civilizations, said in a press release.

Cline, who co-directed the project, continued, “This is a hugely significant discovery — it’s a wine cellar that, to our knowledge, is largely unmatched in its age and size.”

The 40 jars have a capacity of roughly 8453.5 cups, meaning the cellar could have held the equivalent of nearly 3,000 bottles of reds and whites.

“The wine cellar was located near a hall where banquets took place, a place where the Kabri elite and possibly foreign guests consumed goat meat and wine,” said the other co-director Yasur-Landau, chair of the Department of Maritime Civilizations at the University of Haifa. “The wine cellar and the banquet hall were destroyed during the same violent event, perhaps an earthquake, which covered them with thick debris of mud bricks and plaster.”

Andrew Koh of Brandeis University also worked on the project. Using a technique called organic residue analysis, he studied some of the jar fragments. They yielded traces of tartaric and syringic acids, both key components in wine. Koh also detected other ingredients popular in ancient wine making (and modern day cocktails!), including honey, mint, cinnamon bark, juniper berries and resins.

The Julia Child of wine during those times must have come from ancient Egypt, because the recipe is similar to medicinal wines that were popular for 2,000 or so years in early Egypt. News of the tasty mixture must have spread to Israel.

Read more at Discovery News

Black Hole Birth Spawned Record-Breaking Blast

On April 27, a powerful flash of radiation erupted from deep space. The flash, a gamma-ray burst (GRB), was the brightest on record, challenging some of the leading theories on how the most powerful explosions in the known Universe occur.

Triggered by the sudden collapse of a dying massive star, GRBs are thought to be energized by the resulting black hole that forms in its wake. The black hole birthing drives relativistic particles through the collapsing star material, generating a shock wave, producing a highly collimated beam of gamma-ray radiation. GRBs are considered to be the more energetic cousins of supernovae, but for the first time, this particular GRB — called GRB 130427A — was seen to occur alongside a supernova; an unprecedented observation.

“We normally detect GRBs at great distance, meaning they usually appear quite faint. In this case the burst happened only a quarter of the way across the Universe meaning it was very bright. On this occasion, a powerful supernova was also produced, something we have not recorded before alongside a powerful GRB and we will now be seeking to understand this occurrence,” said Paul O’Brien, of the University of Leicester, who collaborated on one of the five papers devoted to GRB 130427A published in the journals Science and Astrophysical Journal Letters on Thursday (Nov. 21).

Another noteworthy factor of this event was the high number of observatories in space and on the ground that were able to slew in the direction of GRB 130427A just after it occurred. The initial discovery was made almost simultaneously by NASA’s orbiting Swift Gamma-Ray Burst Mission and Fermi Gamma-ray Space Telescope, then an alert was sent out to observatories on the ground such as the Rapid Telescopes for Optical Response (RAPTOR) project to watch the gamma-ray glow brighten.

Even NASA’s newest X-ray space observatory, the Nuclear Spectroscopic Telescope Array (NuSTAR), was able to get in on the act, recording hard X-ray data in the GRB’s afterglow.

“We expect to see an event like this only once or twice a century, so we’re fortunate it happened when we had the appropriate collection of sensitive space telescopes with complementary capabilities available to see it,” said Paul Hertz, director of NASA’s Astrophysics Division in Washington.

Due to GRB 130427A’s relatively close proximity and the vast quantities of data collected from the multi-instrument campaign, it has become something of a GRB “Petri dish.”

“The rapid reaction of Swift has enabled us to discover many new and unexpected aspects of GRBs, the strong confirmation of the basic theory by this new very bright burst reassures us that we are on the right track in understanding these extraordinary explosions,” said Julian Osborne, Swift team leader at the University of Leicester.

Although astrophysicists will be picking through the data for some time to come, this event has already poked a couple of holes in our understanding of how GRBs work. For example, as highlighted in Fermi data, just as the optical light from the GRB peaked, there was an anomalous spike in highly energetic gamma-rays. The energies associated with this gamma-ray peak topped out at 95 GeV, the most powerful radiation ever seen from a GRB event.

Read more at Discovery News

Nov 21, 2013

Darwin's Frogs Croaking Thanks to Deadly Fungus

Male Darwin's frogs raise young in their mouths, protecting them from predators until they have matured for weeks, when the fathers regurgitate them into the world. But nothing can protect them from a deadly fungus, which has helped push one of the two species of these frogs to probable extinction, and driven a decline in the second variety, new research shows.

The fungus, known as Batrachochytrium dendrobatidis, or chytrid fungus, has spread throughout the world and devastated many amphibian populations. But this is one of the first instances in which the fungus has been directly implicated in the disappearance of such a widely known species, researchers said.

Researchers looked at museum specimens of both species and found that the fungus started showing up in these and other frogs in the 1970s, about when populations of both began to decline, according to a study published today (Nov. 20) in the journal PLOS ONE.

One of the species, the northern Darwin's frog (Rhinoderma rufum), hasn't been seen since 1980 and is likely extinct. The fungus is "probably the main reason" for the frog's disappearance, said Marcus Rowcliffe, a researcher at the Zoological Society of London who wasn't involved in the present study.

The southern Darwin's frog (Rhinoderma darwinii) is still around, but has declined faster than previously thought in recent years, said Claudio Soto-Azat, a study co-author and researcher at Andrés Bello University in Santiago, Chile, who did research for the study while a student at the Zoological Society of London.

The researchers found that a small percentage of southern Darwin's frogs were infected with the fungus, although at lower rates than other species. This could mean that the fungus more easily kills them, compared to other frogs, the study noted (whereas other species can live longer with the disease, and thus more of them are found alive suffering from the infection). They also found that populations of Darwin's frogs were lower in areas with higher rates of fungal infection. In one instance in 2007, 30 wild-caught southern Darwin's frogs were sent to be captive-bred in Germany, but all 30 died from the fungus.

The fungus may have been spread to Chile by African clawed frogs, brought to the region in part to be used for pregnancy tests, in the mid-20th century. These frogs laid eggs when injected with pregnant women's urine.

Darwin's frogs are the only known species of frogs where males can get "pregnant" and hold the young within a compartment of their mouth as the tadpoles mature. They are named for Charles Darwin, who happened upon one of the two species in 1834.

Another PLOS ONE study published in June by Soto-Azat and colleagues estimated that the northern Darwin's frog bit the dust in 1982.

Read more at Discovery News

The Case of the Spinning Egyptian Statue: Solved

An ancient statue in a British museum was caught on camera mysteriously turning in its locked display case in June. The footage mystified many and made international news. According to an article in the “Manchester Evening News:”

An ancient Egyptian statue has spooked museum bosses — after it mysteriously started to spin round in a display case. The 10-inch tall relic, which dates back to 1800 B.C., was found in a mummy’s tomb and has been at the Manchester Museum for 80 years.   But in recent weeks, curators have been left scratching their heads after they kept finding it facing the wrong way. Experts decided to monitor the room on time-lapse video and were astonished to see it clearly show the statuette spinning 180 degrees — with nobody going near it.
  • ”Maybe the statue has a material component that reacts to the rotation of the earth.”
  • ”Perhaps there is magnetism that eventually turns it to face north or south? Pulled based upon the position of the sun/moon?”
  • ”Magnetics are a possibility — some rocks have crystalline structures which can store charge.”
  • ”It seems to only be turning while exposed to sunlight. It doesn’t move at all when it’s dark.”
  • ”It’s releasing some kind of gas and being on glass it’s enough to let it rotate.”
  • ”It seems to turn at a uniform rate whenever the lights are on. Could the transformer for the lights be causing a vibration at just the right frequency?”
  • ”The sacred geometry of a pyramid creates a natural swirling vortex of energy that beams out of the top…. Perhaps this statue is emanating the same energy that pyramids do. If it’s sitting on a very clean, polished surface, it’s possible that energy is just enough to spin in it around slowly.”
For each explanation — notably including the one that turned out to be correct — counter-arguments and counter-evidence was offered. Earlier this week, a scientist finally found the definitive explanation. As a BBC News report explained:

Vibrations expert Steve Gosling placed a specialist three-axis sensor under Neb-Senu’s glass cabinet to record its movement over 24 hours. The sensor revealed traffic and footfall vibrations at busy times of the day, such as 18:00 GMT and 07:00 GMT, caused the statue to rotate.   Mr. Gosling, of 24 Acoustics engineering noise consultancy, said: “The vibration is a combination of multiple sources so there’s buses outside on the busy road, there’s footfall activity.” Movement ceased overnight. “There’s a lump at the bottom which makes it more susceptible to vibrations than the others which have a flat base,” Mr. Gosling added.

This investigation, done on behalf of a myth-busting British television show, confirmed what many scientists had long suspected. In fact that exact explanation appeared six months ago in a Discovery News analysis of this mystery shortly after it happened:

“If the object is placed on a smooth surface with very little friction to hold it in place — and unless the glass case (and the floor underneath it) is perfectly level — the statue will turn. As with the bump on the bottom of the statue, the tilt does not need to be noticeable to be effective. The statue is housed in an ordinary glass museum case, not a laboratory platform scientifically calibrated to maintain perfect level and resist vibrations. This would also explain why the statue rotates on its axis, turning more or less in one spot instead of wandering around the display case like a lost child looking for its mummy.”

Now that the mystery has been definitively debunked, some are reacting with dismissals such as “So what? It was obvious,” or “Anyone could have figured it out.”

Read more at Discovery News

Sea Lions React To Sonar

It's not only whales that are affected by military sonar, but California sea lions respond to the underwater noise as well, according to a new study in the journal Marine Environmental Research. Experiments with captive sea lions show that the louder the military style sonar signals the marine mammals are exposed to, the more they react, particularly if they are younger sea lions.

In the experiment, fifteen sea lions were exposed to a simulated tactical sonar signal (not directly physically harmful) for one second at varying levels of loudness. The sea lions were trained to swim across an enclosure, touch a paddle and return to the starting point.

The simulated sonar was turned on when the sea lions crossed the middle of the enclosure. Among the sea lion reactions were such things as refusing to participate, hauling out of the water to avoid the noise, changes in their breathing rate and staying underwater longer. The experiment was conducted using methods based on pharmaceutical studies on “dose and response” to medications.

The work is part of the ongoing effort by the Navy and independent scientists to learn how sonar affects marine mammals and makes some species apparently lose their way and get beached, as has believed to have happened when Navy ships have employed the sonar technology they use to detect enemy submarines.

“The problem is that there isn't much data out there,” said the National Marine Mammal Foundation's Dorian Houser, the lead author of the study. What scientists and the Navy have had is a hodgepodge of data that has amounted to little more than wild guesses about how specific animals respond to the military sonar. “The regulatory agency is forced to make this decision based on very little information.”

And so they throw together what little is known about large baleen whales with toothed whales, for instance, despite the vast differences in the animals and extrapolate.

“It's a tough issue to crack,” agreed Brandon Southall, a marine mammal researcher at the University of California at Santa Cruz, and president of Southall Environmental Associates. “You're asking how a pattern of behavior changes with different species and different individuals.”

Right now there are basically two lines of research underway. One is with captive animals, like what Houser and his colleagues are doing. The other is studying wild animals in the oceans, which is Southall's specialty.

Read more at Discovery News

Ancient and Stealthy: Methuselah Brown Dwarfs Found

Using data from NASA’s Wide-field Infrared Survey Explorer (WISE), astronomers have detected two ancient “failed stars” that are likely 10 billion years old. The discovery of the ancient pair has led to an estimate that there are likely billions of these previously unseen brown dwarfs barreling through our galaxy at high speed.

The University of Hertfordshire astronomers, led by David Pinfield, clocked the two brown dwarfs traveling at a breakneck velocity of 100-200 kilometers per second, far faster than younger stars and brown dwarfs. WISE 0013+0634 and WISE 0833+0052 were spotted through the detection of their very faint infrared signals in the constellations Pisces and Hydra, respectively.

Brown dwarfs form the stellar bridge between massive planets and small stars. They possess characteristics of both stars and planets, but cannot be defined as either. Brown dwarfs are too small to sustain nuclear fusion in their cores, hence the “failed star” moniker, but they lack material stratification through their bodies, so they don’t fall into the planetary category either — they could just as easily be nicknamed “overachieving planets.” As brown dwarfs are cool objects — these two new discoveries are thought to have temperatures between 250-600 degrees Celsius (520-870 Kelvin or 480-1,100 Fahrenheit) — only the most sensitive of infrared observatories can detect their weak infrared emissions.

With the help of follow-up studies by ground-based observatories, the researchers identified an abundance of hydrogen in the brown dwarfs’ atmospheres. Through spectroscopic analysis, they also revealed a dearth of heavy elements commonly found in younger stellar objects. Heavy elements (i.e. any element heavier than hydrogen and helium) are created in the cores of massive stars and supernovae — the low metallicity of these two objects therefore betray their ancient origins; they were formed from primordial interstellar gases when our galaxy was a fraction of the age it is now.

Nearby stars belong to one of three stellar populations: the thin disk, thick disk or halo. The latter two are known to contain some of the most ancient of stars. Also, stars in the thick disk and halo also have the highest velocities, a characteristic the two brown dwarfs possess. But owed to their very weak infrared emission, Methuselah brown dwarfs like WISE 0013+0634 and WISE 0833+0052 are very hard to detect, requiring some very clever astronomical techniques and data analysis.

According to the researchers, 97 percent of local stars belong to the thin disk population, including our comparatively young sun, while just 3 percent belong in the thick disk and halo populations. Considering 70 billion brown dwarfs are thought to live in the thin disk, if the number of stars is representative of the population of brown dwarfs, 3 percent represents at least 2 billion hard-to-detect brown dwarfs that formed in the Milky Way’s formative years, but are now zooming around the thick disk and halo regions.

Read more at Discovery News

Nov 20, 2013

Neanderthal Viruses Found in Modern Humans

Ancient viruses from Neanderthals have been found in modern human DNA by researchers at Oxford University and Plymouth University.

The researchers compared genetic data from fossils of Neanderthals and another group of ancient human ancestors called Denisovans to data from modern-day cancer patients. They found evidence of Neanderthal and Denisovan viruses in the modern human DNA, suggesting that the viruses originated in our common ancestors more than half a million years ago.

This latest finding, reported in Current Biology, will enable scientists to further investigate possible links between ancient viruses and modern diseases including HIV and cancer, and was supported by the Wellcome Trust and Medical Research Council (MRC).

Around 8% of human DNA is made up of 'endogenous retroviruses' (ERVs), DNA sequences from viruses which pass from generation to generation. This is part of the 90% of our DNA with no known function, sometimes called 'junk' DNA.

'I wouldn't write it off as "junk" just because we don't know what it does yet,' said Dr Gkikas Magiorkinis, an MRC Fellow at Oxford University's Department of Zoology. 'Under certain circumstances, two "junk" viruses can combine to cause disease -- we've seen this many times in animals already. ERVs have been shown to cause cancer when activated by bacteria in mice with weakened immune systems.'

Dr Gkikas and colleagues are now looking to further investigate these ancient viruses, belonging to the HML2 family of viruses, for possible links with cancer and HIV.

'How HIV patients respond to HML2 is related to how fast a patient will progress to AIDS, so there is clearly a connection there,' said Dr Magiorkinis, co-author of the latest study. 'HIV patients are also at much higher risk of developing cancer, for reasons that are poorly-understood. It is possible that some of the risk factors are genetic, and may be shared with HML2. They also become reactivated in cancer and HIV infection, so might prove useful as a therapy target in the future.'

The team are now investigating whether these ancient viruses affect a person's risk of developing diseases such as cancer. Combining evolutionary theory and population genetics with cutting-edge genetic sequencing technology, they will test if these viruses are still active or cause disease in modern humans.

'Using modern DNA sequencing of 300 patients, we should be able to see how widespread these viruses are in the modern population. We would expect viruses with no negative effects to have spread throughout most of the modern population, as there would be no evolutionary pressure against it. If we find that these viruses are less common than expected, this may indicate that the viruses have been inactivated by chance or that they increase mortality, for example through increased cancer risk,' said Dr Robert Belshaw, formerly of Oxford University and now a lecturer at Plymouth University, who led the research.

Read more at Science Daily

'Dueling Dinosaur' Fossils Fail to Sell

Two fossilized dinosaurs discovered side-by-side in the Montana badlands failed to sell when they went under the hammer in New York on Tuesday (Nov. 19), despite projections that they would break auction records.

Bonhams auction house, which handled the sale of the so-called Dueling Dinosaurs, had estimated the bones would sell for between $7 million $9 million. Bidding started at $3 million and stopped at $5.5 million, however, failing to meet the auction house's undisclosed reserve.

So for now at least, the famed T. rex called Sue remains the most expensive fossil specimen to be sold at public auction. The Field Museum in Chicago bought that dinosaur in 1997 for $8.36 million, blowing away expectations at the time that it would sell for around $1 million.

Auction house officials said they are hopeful the dinosaur duo will find a home and are now entering into negotiations with interested U.S. institutions.

"The story isn't over," said Thomas Lindgren, co-consulting director of the natural history department at Bonhams in Los Angeles, who put together today's natural history auction in New York, which drew a crowd prospective buyers, curious onlookers and reporters.

"Behind the scenes, before the sale occurred today, I've had museums mention that they have difficulty coming up with funds this quickly, but should the lot not sell — which of course occurred — they want us to be in negotiations immediately," Lindgren said during a press conference after the sale. "I'm very confident we're going to find a scientific home for these dinosaurs."

Locked in the same chunk of earth, the two dinosaurs were being auctioned off as a single specimen, still encased in dirt and their plaster field jackets. Some paleontologists had expressed fears ahead of the auction that the dinosaurs could be lost to science should they end up in the hands of a private collector who has no desire to loan or donate them to a public institution.

Lindgren said he had been guiding the sale toward the institutions and donors that would house the fossils in a public collection, adding that he wasn't thrilled with the idea that they could "disappear to a private individual who would not make them available."

Fossil hunters uncovered the massive herbivore and the meat-eater on a ranch in the Montana badlands in 2006. The beasts' poses suggest they were engaged in mortal combat, and hence the nickname of the Dueling Dinosaurs.

Billed as the most complete dinosaur fossils from North America's Late Cretaceous rocks, the Dueling Dinosaurs are extremely well articulated and bits of skin even cling to the sand that surrounds the bones.

The creatures in question are a ceratopsid — perhaps a new species of Triceratops — and a tyrannosaurid — possibly a Nanotyrannus lancensis, according to Bonhams.

Researchers are often loathe to put a price tag on their study specimens, and some objected to the sale on scientific grounds, arguing that the fossils' true importance, identity and death saga (i.e., whether they represent fierce combatants or perhaps a pair of unlucky strangers washed away in a flood) cannot be known until the bones are examined in peer-reviewed studies.

The fossils previously had been offered to museums in the United States, but they were turned down because of the prohibitive price, by some accounts. Hans-Dieter Sues, curator of vertebrate paleontology at the Smithsonian's National Museum of Natural History, told LiveScience earlier this month that his institution was offered the fossils for $15 million.

Read more at Discovery News

Ancient Siberian Skeletons Confirm Native American Origins

The DNA gleaned from two ancient Siberian skeletons is related to that of modern-day Native Americans and western Eurasians, new research suggests.

The genetic material from the ancient Siberians provides additional evidence that the ancestors of Native Americans made the arduous trek from Siberia across the Bering Strait into the Americas.

But it also reveals there were multiple waves of migrations in Asia around this time, said Mark Hubbe, a biological anthropologist at The Ohio State University who was not involved in the study.

"This brings a new level of complexity to what we think happened in Asia," Hubbe told LiveScience.

Ancient migrations

Several genetic clues indicate that Native Americans came from a population that once inhabited Siberia and crossed the Bering Strait between 20,000 and 15,000 years ago.

Between 1928 and 1958, Russian scientists excavated a Siberian site in Mal'ta, Russia, near Lake Baikal, and unearthed a trove of Venus figurines along with the skeleton of a juvenile, all dating back approximately 24,000 years. The figurines were intriguing, because they were similar in style to ones made by European hunter-gatherers.

European relatives

To trace the ancestry of these ancient people, Maanasa Raghavan, a researcher at the University of Copenhagen in Denmark, and colleagues managed to extract DNA from the ancient skeleton.

The team found that the mitochondrial DNA, or genetic material carried in the cytoplasm of cells that is passed through the maternal line, came from a lineage known as U, which is rare or extinct now, but was once common in hunter-gatherers from Europe during the Paleolithic Period.

The team also sequenced the male sex chromosome (Y chromosome), which traces the paternal lineage of the skeleton. On the paternal side, the ancient boy came from a lineage known as R, which is now found in southern Siberia and western Eurasia. The R lineage is also a sister group to one common in Native Americans.

The researchers estimate that between 14 and 38 percent of Native American ancestry could come from this ancestral population, with the remaining portion coming from ancient East Asians.

DNA from a 17,000-year-old skeleton found in south central Siberia showed signs of being from the same genetic lineage as the Ma'lta specimen.

Previously, researchers had thought that people migrated from Europe into east Asia, and then entered Siberia from the south in a fairly linear expansion, Hubbe said. But the new results suggest the Siberian inhabitants may have come from the West, he said. That suggests Asia experienced multiple, crisscrossing waves of migration, he said.

However, because the skeletons are so old, it's important to rule out the possibility that the DNA was contaminated, Theodore Schurr, an anthropologist at the University of Pennsylvania who was not involved in the study, wrote in an email.

Read more at Discovery News

Universe's Largest Structure is a Cosmic Conundrum

Astronomers have found a mind-bogglingly large structure -- so big it takes light 10 billion years to traverse -- in a distant part of the universe.

The discovery poses a conundrum to a fundamental tenet of modern cosmology, which posits that matter should appear to be distributed uniformly if viewed at a large enough scale.

The newly found structure is more than double the size of the previous record-holder, a cluster of 73 quasars referred to as the Huge-LQG, or Large Quasar Group, which spans 4 billion light-years. It is six times larger than the 1.4-billion-light year diameter Sloan Great Wall.

Light travels at about 671 million miles per hour, or about 6 trillion miles per year.

Scientists found the new structure by mapping the locations of gamma ray bursts. These fleeting, but high-energy outbursts are believed to be caused by exploding massive stars.

"It's a great tracer of where something was," astronomer Jon Hakkila, with the College of Charleston in South Carolina, told Discovery News.

Because bigger stars form in areas with more material in general, gamma ray bursts can give astronomers a rough estimate of how much matter a particular region contains.

“We’re treating each (gamma ray burst) source as if it’s a pin in the map and it’s sticking to something,” Hakkila said.

After accounting for potential survey biases -- such as NASA's Swift telescope and other gamma ray trackers looking more often in one part of the sky or another -- scientists found a region roughly 10 billion light-years away in the direction of the constellations Hercules and Corona Borealis that had a disproportionate number of gamma ray bursts.

Extrapolating from the locations of the bursts, scientists estimate the structure from which they came spans approximately 10 billion light-years in diameter.

Read more at Discovery News

Nov 19, 2013

Biologists Find an Evolutionary Facebook for Monkeys and Apes

Why do the faces of some primates contain so many different colors -- black, blue, red, orange and white -- that are mixed in all kinds of combinations and often striking patterns while other primate faces are quite plain?

UCLA biologists reported last year on the evolution of 129 primate faces in species from Central and South America. This research team now reports on the faces of 139 Old World African and Asian primate species that have been diversifying over some 25 million years.

With these Old World monkeys and apes, the species that are more social have more complex facial patterns, the biologists found. Species that have smaller group sizes tend to have simpler faces with fewer colors, perhaps because the presence of more color patches in the face results in greater potential for facial variation across individuals within species. This variation could aid in identification, which may be a more difficult task in larger groups.

Species that live in the same habitat with other closely related species tend to have more complex facial patterns, suggesting that complex faces may also aid in species recognition, the life scientists found.

"Humans are crazy for Facebook, but our research suggests that primates have been relying on the face to tell friends from competitors for the last 50 million years and that social pressures have guided the evolution of the enormous diversity of faces we see across the group today," said Michael Alfaro, an associate professor of ecology and evolutionary biology in the UCLA College of Letters and Science and senior author of the study.

"Faces are really important to how monkeys and apes can tell one another apart," he said. "We think the color patterns have to do both with the importance of telling individuals of your own species apart from closely related species and for social communication among members of the same species."

Most Old World monkeys and apes are social, and some species, like the mandrills, can live in groups with up to 800 members, said co-author Jessica Lynch Alfaro, an adjunct assistant professor in the UCLA Department of Anthropology and UCLA's Institute for Society and Genetics. At the other extreme are solitary species, like the orangutans. In most orangutan populations, adult males travel and sleep alone, and females are accompanied only by their young, she said. Some primates, like chimpanzees, have "fission-fusion societies," where they break up into small sub-groups and come together occasionally in very large communities. Others, like the hamadryas baboons, have tiered societies with harems, clans, bands and troops, she said.

"Our research suggests increasing group size puts more pressure on the evolution of coloration across different sub-regions of the face," Michael Alfaro said.

This allows members of a species to have "more communication avenues, a greater repertoire of facial vocabulary, which is advantageous if you're interacting with many members of your species," he said.

The research, federally funded by the National Science Foundation and supported through a postdoctoral fellowship from the UCLA Institute for Society and Genetics, was published Nov. 11 in the journal Nature Communications.

Lead study author Sharlene Santana used photographs of primate faces for her analysis and devised a new method to quantify the complex patterns of primate faces. She divided each face into several regions; classified the color of each part of the face, including the hair and skin; and assigned a score based on the total number of different colors across the facial regions. This numerical score is called the "facial complexity" score. The life scientists then studied how the complexity scores of primate faces were related to primates' social systems.

The habitat where species live presents many potential pressures that could have influenced the evolution of facial coloration. To assess how facial colors are related to physical environments, the researchers analyzed environmental variables such as geographic location, canopy density, rainfall and temperature. They also used statistical methods that took into account the evolutionary history and relationships among the primate groups to better understand the evolution of facial diversity and complexity.

While facial complexity was related to social variables, such as group size and the number of closely related species in the same habitat, facial pigmentation was best explained by ecological and spatial factors. Where a species lives is a good predictor of its degree of facial pigmentation -- how light or dark the face is.

"Our map shows clearly the geographic trend in Africa of primate faces getting darker nearer to the equator and lighter as we move farther away from the equator," Lynch Alfaro said. "This is the same trend we see on an intra-species level for human skin pigmentation around the globe."

Species living in more tropical and more densely forested habitats also tend to have darker, more pigmented faces. But the complexity of facial color patterns is not related to habitat type.

"We found that for African primates, faces tend to be light or dark depending on how open or closed the habitat is and on how much light the habitat receives," Alfaro said. "We also found that no matter where you live, if your species has a large social group, then your face tends to be more complex. It will tend to be darker and more complex if you're in a closed habitat in a large social group, and it will tend to be lighter and more complex if you're in an open habitat with a large social group. Darkness or lightness is explained by geography and habitat type. Facial complexity is better explained by the size of your social group."

In their research on primates from Central and South America published last year, the scientists were surprised to find a different pattern. For these primates, species that lived in larger groups had more plain facial patterns.

"We expected to find similar trends across all primate radiations -- that is, that the faces of highly social species would have more complex patterning," said Santana, who conducted the research as a postdoctoral fellow with the UCLA Department of Ecology and Evolutionary Biology and UCLA's Institute for Society and Genetics and who is now an assistant professor at the University of Washington and curator of mammals at the Burke Museum of Natural History and Culture. "We were surprised by the results in our original study on neotropical (Central and South American) primates."

In the new study, they did find the predicted trends, but they also found differences across primate groups -- differences they said they found intriguing. Are primate groups using their faces differently?

"In the present study, great apes had significantly lower facial complexity compared to monkeys," Lynch Alfaro said. "This may be because apes are using their faces for highly complex facial expressions and these expressions would be obscured by more complex facial color patterns. There may be competing pressures for and against facial pattern complexity in large groups, and different lineages may solve this problem in different ways."

"Our research shows that being more or less social is a key explanation for the facial diversity that we see," Alfaro said. "Ecology is also important, such as camouflage and thermal regulation, but our research suggests that faces have evolved along with the diversity of social behaviors in primates, and that is the big cause of facial diversity."

Read more at Science Daily

Two-Headed Ray Fetus Found in Australia

They say two heads are better than one. That may or may not be true, but at the very least, two heads are more interesting.

While checking up on the pregnant female rays that he was caring for in an aquarium, Australian researcher Leonardo Guida saw that some of the animals had given birth, in April of this year. As he made note of the baby rays, an "oddly shaped, pale object in the water" caught his attention.

The object turned out to be a stillborn ray … with two heads. This is the first two-headed ray or shark discovered in Australia, and one of only a few examples worldwide of this rare birth defect found in sharks and rays, said Guida, who is a doctoral student at Monash University in Melbourne.

The defect arises when the neural tube (like a spinal cord) in a single fertilized egg is duplicated, which can happen as the result of a genetic defect or for other unknown reasons. It can also happen when an embryo begins to divide into two to form twins, but is stopped prematurely.

The cause in this case "is unknown but is likely to have been a developmental problem and not a genetic mutation per se," said Guida, co-author of a study describing the ray published Nov. 15 in the journal Marine and Freshwater Research. "Pollutants can potentially cause developmental issues, however we did not test for this nor were we able to determine the probable cause."

The researchers caught the southern fiddler rays (Trygonorrhina dumerilii) by hand while scuba diving in Swan Bay, a semi-enclosed section of Port Phillip Bay south of Melbourne, home to heavy ship traffic. The bay has recently undergone extensive dredging to enlarge shipping channels, re-suspending contaminated sediment into the ocean, according to the study. This developed, combined with the fact that rays eat bottom-dwelling creatures, may have exposed these animals to significant levels of pollutants. But whether or not they could've caused this birth defect is unknown, the study noted.

Other similar findings include the discovery of a two-headed bull shark fetus off Florida.

"There have been a number of reports of deformed shark and ray embryos in recent years— two heads, one eye, etc.," said David Shiffman, a shark researcher and doctoral student at the University of Miami. There's no evidence to suggest these defects represent a new phenomenon or that they are harmful to shark populations as a whole, said Shiffman, who wasn't involved in the ray study.

"However, we're learning about the deformed embryos, because [in many cases] fishermen are killing the sharks," Shiffman said.

Read more at Discovery News

'Meat Mummies' Fed Egyptian Royals After Death

Care for some ribs? The royal mummies of ancient Egypt apparently did, as a new study finds that "meat mummies" left in Egyptian tombs as sustenance for the afterlife were treated with elaborate balms to preserve them.

Mummified cuts of meat are common finds in ancient Egyptian burials, with the oldest dating back to at least 3300 B.C. The tradition extended into the latest periods of mummification in the fourth century A.D. The famous pharaoh King Tutankhamun went to his final resting place accompanied by 48 cases of beef and poultry.

But meat mummies have been mostly unstudied until now. University of Bristol biogeochemist Richard Evershed and his colleagues were curious about how these cuts were prepared. They also wondered if the mummification methods for meat differed from how Egyptians mummified people or pets.

The team analyzed four samples from meat mummies archived at the Cairo and British museums. The oldest was a rack of cattle ribs from the tomb of Tjuiu, an Egyptian noblewoman, and her courtier Yuya. The beef dates back to between 1386 B.C. and 1349 B.C.

The second sample dated to between 1064 B.C. and 948 B.C. and consisted of meat from a calf found in the tomb of Isetemkheb D, a sister and wife to a high priest in Thebes. The final two samples were from the tomb of a Theban priestess, Henutmehyt, who died around 1290 B.C. One of the meat mummies found in Henutmehyt's tomb was duck, and the other was probably goat.

The researchers conducted a chemical analysis of the bandages or the meat itself in all four samples. They found that animal fat coated the bandages of the calf and goat mummies; in the case of the calf, the fat was on bandages not in contact with the meat, suggesting it had been smeared on as a preservative rather than seeping through as grease.

The most intriguing chemical profile appeared on the beef mummy, however. The bandaging around the mummy contained remnants of an elaborate balm made of fat or oil and resin from a Pistacia tree, a shrubby desert plant. This resin was a luxury item in ancient Egypt, Evershed and his colleagues report today (Nov. 18) in the journal Proceedings of the National Academy of Sciences. It was used as incense and varnish on high-quality coffins, but it was not used as a human mummification resin for at least 600 years after the deaths of Tjuiu and Yuya.

Read more at Discovery News

Dino-Era Water Trapped Under Impact Crater

More than one kilometer beneath the Chesapeake Bay in Virginia, geologists discovered 100- to 150-million-year-old water from the Atlantic Ocean’s infancy. The ancient water hid under a more recent 56-mile-wide crater left after a massive rock or block of ice nailed the Earth near what is now the entrance to the bay.

U.S. Geological Survey (USGS) hydrologists didn’t know the water beneath the crater dated from dino days until they analyzed the chemicals in the water. The water held forms of chloride and bromide, along with other chemicals, that allowed the scientists to estimate the water’s age. And while older water is known from Canada, the Chesapeake Bay impact water is now the oldest large body of water known on the planet.

“Previous evidence for temperature and salinity levels of geologic-era oceans around the globe have been estimated indirectly from various types of evidence in deep sediment cores,” said lead author Ward Sanford, USGS research hydrologist, in a press release. “In contrast, our study identifies ancient seawater that remains in place in its geologic setting, enabling us to provide a direct estimate of its age and salinity.” Sanford and colleagues published their findings in the journal Nature.

The ancient water contained twice the salt content of the modern ocean and dates from the early Cretaceous Period, when dinosaurs dominated the planet and the newborn north Atlantic was more of a lake than an ocean.

In the late Jurassic Period, 150 million years ago, pieces of the Earth’s crust, called tectonic plates, split to divide Europe from North America and Africa. This split formed a rift basin filled with extremely salty water that would later become the Atlantic Ocean. However the Atlantic would have to wait 50 million years until the mid-Cretaceous for a space to open between what is now Central and South America, just as the narrow Strait of Gibraltar now allows the Atlantic Ocean and Mediterranean Sea to mingle.

Before the north Atlantic connected with the rest of the world’s waters, some of that briny water became trapped underground beneath a coastal plain and isolated. The water remained largely unchanged until approximately 35 million years ago when a meteor or comet slammed into the Earth during the late Eocene Epoch. That impact created massive tsunamis that swept far inland and devastated the Atlantic coast of North America, yet helped to preserve the Cretaceous ocean water.

Read more at Discovery News

Nov 18, 2013

Amber Provides New Insights Into the Evolution of Earth's Atmosphere: Low Oxygen Levels for Dinosaurs

An international team of researchers led by Ralf Tappert, University of Innsbruck, reconstructed the composition of Earth's atmosphere of the last 220 million years by analyzing modern and fossil plant resins. The results suggest that atmospheric oxygen was considerably lower in Earth's geological past than previously assumed. This new study questions some of the current theories about the evolution of climate and life, including the causes for the gigantism of dinosaurs.

Scientists encounter big challenges when reconstructing atmospheric compositions in Earth's geological past because of the lack of useable sample material. One of the few organic materials that may preserve reliable data of Earth's geological history over millions of years are fossil resins (e.g. amber). "Compared to other organic matter, amber has the advantage that it remains chemically and isotopically almost unchanged over long periods of geological time," explains Ralf Tappert from the Institute of Mineralogy and Petrography at the University of Innsbruck. The mineralogist and his colleagues from the University of Alberta in Canada and universities in the USA and Spain have produced a comprehensive study of the chemical composition of Earth's atmosphere since the Triassic period.

The study has been published in the journal Geochimica et Cosmochimica Acta. The interdisciplinary team, consisting of mineralogists, paleontologists and geochemists, use the preserving properties of plant resins, caused by polymerization, for their study. "During photosynthesis plants bind atmospheric carbon, whose isotopic composition is preserved in resins over millions of years, and from this, we can infer atmospheric oxygen concentrations," explains Ralf Tappert. The information about oxygen concentration comes from the isotopic composition of carbon or rather from the ratio between the stable carbon isotopes 12C and 13C.

Atmospheric oxygen between 10 and 15 percent

The research team analyzed a total of 538 amber samples from from well-known amber deposits worldwide, with the oldest samples being approximately 220 million years old and recovered from the Dolomites in Italy. The team also compared fossil amber with modern resins to test the validity of the data. The results of this comprehensive study suggest that atmospheric oxygen during most of the past 220 million years was considerably lower than today's 21 percent. "We suggest numbers between 10 and 15 percent," says Tappert. These oxygen concentrations are not only lower than today but also considerably lower than the majority of previous investigations propose for the same time period. For the Cretaceous period (65 -- 145 million years ago), for example, up to 30 percent atmospheric oxygen has been suggested previously.

Effects on climate and environment

The researchers also relate this low atmospheric oxygen to climatic developments in Earth's history. "We found that particularly low oxygen levels coincided with intervals of elevated global temperatures and high carbon dioxide concentrations," explains Tappert. The mineralogist suggests that oxygen may influence carbon dioxide levels and, under certain circumstances, might even accelerate the influx of carbon dioxide into the atmosphere. "Basically, we are dealing here with simple oxidation reactions that are amplified particularly during intervals of high temperatures such as during the Cretaceous period." The researchers, thus, conclude that an increase in carbon dioxide levels caused by extremely strong vulcanism was accompanied by a decrease of atmospheric oxygen. This becomes particularly apparent when looking at the last 50 million years of geological history. Following the results of this study, the comparably low temperatures of the more recent past (i.e. the Ice Ages) may be attributed to the absence of large scale vulcanism events and an increase in atmospheric oxygen.

Read more at Science Daily

Deformed, Pointy Skull from Dark Ages Unearthed

The skeleton of an ancient aristocratic woman whose head was warped into a deformed, pointy shape has been unearthed in a necropolis in France.

The necropolis, found in the Alsace region of France, contains 38 tombs that span more than 4,000 years, from the Stone Age to the Dark Ages.

Rich valley

The Obernai region where the remains were found contains a river and rich, fertile soil, which has attracted people for thousands of years, Philippe Lefranc, an archaeologist who excavated the Stone Age burials, wrote in an email.

Archaeologists first found the tombs in 2011 while doing a preliminary excavation of the area prior to the start of a big industrial building project. This year, Lefranc and his colleagues went back to do a more in-depth excavation.

They found that the tombs were well preserved by the limestone rock in which they were buried. One of the burials contained 20 tombs of men, women and children.

"The corpses are lying on their backs, with outstretched legs and heads turned westwards," Lefranc said.

The tombs, which date to between 4900 B.C. and 4750 B.C., also contained a few stone vases and tools, along with ornaments such as mother-of-pearl elbow bracelets and collars. The small group may have been a family from a Neolithic farming and animal-herding culture that lived in long houses and buried their dead in cemeteries, Lefranc said.

Eastern transplants

In the second burial, which was in a separate area, they found 18 tombs from either the late Roman period or the early Dark Ages, about 1,650 years ago. One of the tombs held a woman, likely an aristocrat, who had a deformed, flattened forehead.

"The deformation of the skull with the help of bandages (narrow strips of cloth) and small boards is a practice coming from central Asia," Lefranc said in an email. "It was popularized by the Huns and adopted by many German people."

In those times, the deformed, alienlike skull was a privilege reserved for the aristocracy.

"In France, Germany and eastern Europe, these deformed skulls appear in tombs rich in objects," Lefranc said.

Read more at Discovery News

Ancient City Found Beneath Biblical-Era Ruins

Archaeologists have unearthed traces of a previously unknown, 14th-century Canaanite city buried underneath the ruins of another city in Israel.

The traces include an Egyptian amulet of Amenhotep III and several pottery vessels from the Late Bronze Age unearthed at the site of Gezer, an ancient Canaanite city.

Gezer was once a major center that sat at the crossroads of trade routes between Asia and Africa, said Steven Ortiz, a co-director of the site's excavations and a biblical scholar at the Southwestern Baptist Theological Seminary in Fort Worth, Texas.

The remains of the ancient city suggest the site was used for even longer than previously known.

The ancient city of Gezer has been an important site since the Bronze Age, because it sat along the Way of the Sea, or the Via Maris, an ancient trade route that connected Egypt, Syria, Anatolia and Mesopotamia.

The city was ruled over many centuries by Canaanites, Egyptians and Assyrians, and Biblical accounts from roughly the 10th century describe an Egyptian pharaoh giving the city to King Solomon as a wedding gift after marrying his daughter.

"It's always changed hands throughout history," Ortiz told LiveScience.

The site has been excavated for a century, and most of the excavations so far date to the the 10th through eighth centuries B.C. Gezer also holds some of the largest underground water tunnels of antiquity, which were likely used to keep the water supply safe during sieges.

But earlier this summer, Ortiz and his colleague Samuel Wolff of the Israel Antiquities Authority noticed traces of an even more ancient city from centuries before King Solomon's time. Among the layers was a section that dated to about the 14th century B.C., containing a scarab, or beetle, amulet from King Amenhotep III, the grandfather of King Tut. They also found shards of Philistine pottery.

During that period, the ancient site was probably a Canaanite city that was under Egyptian influence.

The findings are consistent with what scholars suspected of the site, said Andrew Vaughn, a biblical scholar and executive director of the American Schools of Oriental Research, who was not involved in the study.

"It's not surprising that a city that was of importance in the biblical kingdoms of Israel and Judah would have an older history and would have played an important political and military role prior to that time," Vaughn told LiveScience. "If you didn't control Gezer, you didn't control the east-west trade route."

Read more at Discovery News

'Gate to Hell' Guardians Recovered in Turkey

Archaeologists digging in Turkey have found the guardians of the "Gate to Hell" -- two unique marble statues which once warned of a deadly cave in the ancient Phrygian city of Hierapolis, near Pamukkale.

Known as Pluto's Gate -- Ploutonion in Greek, Plutonium in Latin -- the cave was celebrated as the portal to the underworld in Greco-Roman mythology and tradition. It was discovered in March by a team led by Francesco D'Andria, professor of classic archaeology at the University of Salento.

"The statues represent two mythological creatures," D'Andria told Discovery News. "One depicts a snake, a clear symbol of the underworld, the other shows Kerberos, or Cerberus, the three-headed watchdog of hell in the Greek mythology."

Rolled onto itself, the snake looks threateningly toward anybody trying to approach it, while the 4-foot-tall Kerberos resembles the Kangal, the Anatolian shepherd dog.

"It's a pretty scary statue," D'Andria said.

The sculptures were found as archaeologists further excavated the area where in March they unearthed the remains of the Plutonium, which included an inscription dedicated to the deities of the underworld -- Pluto and Kore.

The dig revealed the source of the thermal springs, which produce the famous white travertine terraces.

"Pamukkale's springs originate right from this cave," D'Andria said.

Believed to have healing properties, the hot springs made the Roman city of Hierapolis -- now a World Heritage Site -- a popular destination for pilgrimages.

Both marble statues emerged from the thermal water, leaving little doubt that the site was indeed Pluto's Gate. The cave was described in historic sources as filled with lethal mephitic vapors.

"This space is full of a vapor so misty and dense that one can scarcely see the ground. Any animal that passes inside meets instant death," the Greek geographer Strabo (64-63 B.C. to about 24 A.D.) wrote about the site.

"I threw in sparrows and they immediately breathed their last and fell," he added.

"They were instantly killed by the carbon dioxide fumes," D'Andria said.

Strabo's account was confirmed during the excavation, as D'Andria and colleagues found several dead birds and insects near the opening.

In the previous excavation, the archaeologists also found the remains of a temple, a pool and a series of steps placed above the cave -- all matching the descriptions of the site in ancient sources.

The site represented an important destination for pilgrims. People watched the sacred rites from steps above the cave opening, while priests sacrificed bulls to Pluto. The ceremony included leading the animals into the cave, and dragging them out dead.

Only the eunuchs of Cybele, an ancient fertility goddess, were able to enter the hell gate without any apparent damage.

"They hold their breath as much as they can," Strabo wrote, adding that their immunity could have been due to their "menomation," "divine providence" or "certain physical powers that are antidotes against the vapor."

According to D'Andria, the site was a famous destination for rites of incubation. Pilgrims took the waters in the pool near the temple, slept not too far from the cave and received visions and prophecies, in a sort of oracle of Delphi effect. Indeed, the fumes coming from the depths of Hierapolis' phreatic groundwater produced hallucinations.

The popularity of the site is testified by dozens of lamps unearthed in front of the cave opening. Among the most precious objects, the archaeologists also found a marble head representing the goddess Aphrodite.

"These votive offerings shows the relentless vitality of the pagan cults in Hierapolis between the 4th and 6th centuries A.D., when the Roman empire was progressively Christianized by emperors such as Constantine and up to Justinian," Alister Filippini, a researcher in Roman history at the Universities of Palermo, Italy, and Cologne, Germany, told Discovery News.

It is possible that during the 5th century the Plutonium's entrance was blocked, preventing access to the underground cave, so that the related pagan rites could not be performed. However pilgrims continued to venerate the area by leaving offerings to the deities, who were believed to miraculously heal the sick people taking the thermal waters near the Plutonium.

At the same time, between the 4th and 6th centuries, the statues of Kerberos and the snakes were scarred, most likely by Christian pilgrims.

Read more at Discovery News

Nov 17, 2013

Ker-pow! Batkid Saves Gotham City

A five-year-old boy recovering from cancer became a superhero for a day, as San Francisco transformed itself into Gotham City and thousands turned out to see the Batkid fly to the rescue.

Even President Barack Obama got in on the act after the story went viral, sending pint-size caped crusader Miles Scott a video message telling him "Way to go!"

Scott, who was diagnosed with leukemia when he was 18 months old, was cheered as he roared out in his Batmobile to nab arch-villain Riddler and save a damsel in distress tied to the city's famous tram tracks.

Police chief Greg Suhr ordered his men to help the diminutive crime-fighter take on his nemesis the Penguin, while he also got messages from San Francisco's baseball and NFL teams for his day in the limelight.

"Our hero has arrived. The streets of San Francisco are safe today" the San Francisco 49ers tweeted, as social media went wild for the youngster, prompting huge crowds to follow him.

The story then took off, making national and international news, with live coverage by outlets including CNN.

"I've never seen anything go viral like this, with the outpouring of support from across the world," said Patricia Wilson of Make-a-Wish Foundation, the charity which organized the dream day.

Thousands gathered in the city's Union Square when the Batkid took a break to refuel at a local restaurant. "Even superheroes have to have lunch," explained one TV reporter, surveying the throng stretching across the square.

The city's San Francisco Chronicle printed a special edition for, with a "Gotham City Chronicle" masthead and a screaming headline: "Batkid Saves City!"

The US Attorney's office put out a spoof press release -- datelined "San Francisco/Gotham" -- announcing that the Riddler and the Penguin had been charged with conspiracy and kidnapping.

"Duo faces long prison terms thanks to Batkid," it said.

In Washington, Obama released a message via the Vine video sharing service, looking into the camera and saying "Way to go, Miles! Way to Save Gotham City."

The First Lady added, on her Twitter feed: "Thanks for catching all those bad guys #SFBatKid! You're an inspiration to us all. -mo"

Scott, whose leukemia is currently in remission, was also due to be given the keys to the city by San Francisco Mayor Ed Lee, during his day as the famous comic-book hero.

The US Attorney's press release said "The Riddler" and "The Penguin" were pseudonyms for Edward "E" Nigma, and Oswald Chesterfield Cobblepot.

"We?ve been chasing Nigma and Cobblepot for years and just when I was about to give up hope that we would ever bring them to justice, wouldn't you know it ? Batkid shows up and saves the day,? said US Attorney Melinda Haag.

"I've been involved in some unbelievable cases and I've worked with some pretty remarkable law enforcement officers, but the bravery displayed by Batkid is off the charts. I'm absolutely certain that there is no villain this remarkable superhero can't defeat," she added.

Read more at Discovery News

Volcanic Rumblings Under Antarctic Ice

What could be more trivial and inconsequential than tiny earthquakes in the icy wastes of Antarctica? Plenty, when the quakes might be from magma moving in the crust beneath the West Antarctic Ice Sheet — a possible hint that an eruption is on the way to open the flood gates for water and ice pouring out of that vast region.

Two deep, low-magnitude earthquake swarms recorded by a seismic network in 2010 and 2011 have been detected near what’s called Mount Sidley, but are from the ground under deep ice, according to a new report in Nature Geoscience.

“Such earthquakes occur beneath active volcanoes, are caused by deep magmatic activity and, in some cases, precede eruptions,” writes the team led by Amanda Lough of Washington University. The same sorts of pre-eruption swarms of tiny quakes were recorded at Mount Pinatubo in 1991, they said.

In this case, however, any eruption would happen under 1,400 meters (almost 4,600 feet) of ice, and probably never melt through to the surface. But that wouldn’t stop all that hot rock from melting a lot of ice and drastically increasing the melt water draining from under this gigantic basin. All that liquid water under the ice could also lubricate ice streams so they flow faster. If that was to happen, it would be a new and unwelcome addition to the worrisome problem of polar ice losses from global warming that’s already measurably raising sea levels worldwide.

As additional evidence that the regions volcanoes are not dead, the researchers also cites ice-penetrating radar data which has spotted a plume of volcanic ash buried in the ice. The ash is thought to have come from the nearby Mount Waesche. Based on how fast ice accumulates in the area, the ash is estimated to have rained down on the ice surface about 8,000 years ago — less than the wink of an eye ago in geological terms.

Read more at Discovery News