Jul 20, 2013

Black Bears Return to Missouri Indicates Healthy Forests

For nearly a century, the only bears known to reside in Missouri were on the state flag or in captivity. Unregulated hunting and habitat loss had wiped out most black bears in Missouri, Arkansas and Oklahoma by the 1920s. Now, thanks to a reintroduction program in Arkansas during the 50s and 60s, hundreds of bears amble through the forests of southern Missouri, according to a joint study by University of Missouri, Mississippi State University, and Missouri Department of Conservation biologists, who warn that although the bear population is still small, outdoor recreationists and homeowners should take precautions in the Ozark forest to avoid attracting bears.

"Black bears normally do not attack humans, but they will ransack picnic baskets, tear through garbage bags or even enter buildings looking for food," said Lori Eggert, associate professor of biological sciences in MU's College of Arts and Science. "Although some Missourians may be concerned, the return of black bears to Missouri is actually a good sign. It means parts of the state's forests are returning to a healthy biological balance after nearly two centuries of intensive logging and exploitation."

Eggert and her colleagues used the genetic fingerprints of bears in Missouri to trace their origin back to Arkansas, where thousands of bears now roam. The majority of these animals appear to be descendents of bears originally reintroduced to the region from populations in Minnesota and Manitoba, Canada. Surprisingly, some of the Missouri bears analyzed by Eggert's team had genetic signatures that suggested they were not descended from the northern bears. Further testing may prove that a tiny population of bears managed to survive unnoticed in the Ozark wilderness after the rest of the region's population had died out.

"The larger the gene pool of bears in the region, the healthier the population will be as it recovers," said Eggert. "If they do indeed exist, these remnant populations of black bears may serve as valuable reservoirs of genetic diversity."

If the Missouri population recovers sufficiently, officials someday may allow human hunters to stalk the Show-Me-State's black bears, noted Eggert. The Arkansas Game and Fish Commission allows limited bear hunting in October and November.

Read more at Science Daily

If You're Not Looking for It, You Probably Won't See It

If you were working on something at your computer and a gorilla floated across your computer screen, would you notice it? You would like to think yes, however, research shows that people often miss such events when engaged in a difficult task. This is a phenomenon known as inattentional blindness (IB). In a new study from Brigham and Women's Hospital (BWH) in Boston, researchers have found that even expert searchers, operating in their domain of expertise, are vulnerable to inattentional blindness.

This study published this week Psychological Science.

"When engaged in a demanding task, attention can act like a set of blinders, making it possible for stimuli to pass, undetected, right in front of our eyes," explained Trafton Drew, PhD, post-doctoral researcher at BWH and lead author on this study. "We found that even experts are vulnerable to this phenomenon."

The researchers asked 24 radiologists to perform a familiar lung nodule detection task. They examined five scans; each scan contained an average of 10 nodules. A gorilla, 48 times larger than the average nodule, was inserted in the last scan. The researchers found that 83 percent of radiologists did not report seeing the gorilla. With the help of Melissa Le-Hoa Vo, post-doctoral researcher at BWH, the researchers tracked the eye-movements of the radiologists and found that that the majority of those who missed the gorilla looked directly at it.

"The radiologists missed the gorillas not because they could not see them, but because the way their brains had framed what they were doing. They were looking for cancer nodules, not gorillas," explained Jeremy Wolfe, senior psychologist and director of the Visual Attention Laboratory at BWH. "This study helps illustrate that what we become focused on becomes the center of our world, and it shapes what we can and cannot see."

The researchers note that it would be a mistake to regard these results as an indictment of radiologists and stress that even this high level of expertise does not immunize against inherent attentional limitations of what we perceive. The results suggest that even expert searchers typically only see what they are looking for, and are often unaware of the unexpected. The researchers hope that the results will lead more expert searchers to recognize the important role of attention in determining what the searcher will find and what they may miss.

This work was funded by a NRSA post-doctoral fellowship from the NIBIB to TD.

From Science Daily

Jul 19, 2013

Lizards Show Evolution Is Predictable

If you could hit the reset button on evolution and start over, would essentially the same species appear? Yes, according to a study of Caribbean lizards by researchers at the University of California, Davis, Harvard University and the University of Massachusetts. The work is published July 19 in the journal Science.

The predictability of evolution over timescales of millions of years has long been debated by biologists, said Luke Mahler, a postdoctoral fellow at UC Davis and first author on the paper. For example, the late Stephen Jay Gould predicted that if you "rewound the tape" on evolution and started over, you would get an entirely different outcome, arguing that small events -- a storm that wiped out a particular pond, a poor season for insects -- could have a disproportionate effect.

On the other hand, there are a number of examples of species in similar habitats that evolve independently into similar-looking forms, such as the cichlid fishes of African lakes.

"It's a big question in evolutionary biology, but very hard to test," Mahler said.

Mahler found his test subjects in the Anole lizards that live on four neighboring islands -- Cuba, Hispaniola (the countries of Haiti and the Dominican Republic), Jamaica and Puerto Rico. Anoles began colonizing these islands, all similar in climate and ecology, about 40 million years ago, and once there, they began to multiply, resulting in a diversity of species on each.

The researchers studied 100 of the 119 Anole lizard species from the islands, taking measurements of their bodies from wild and museum specimens and comparing them across islands.

They found a striking degree of convergence -- on each island, evolution had produced a set of very similar-looking lizards occupying similar environmental niches.

"The adaptive radiations match on all four islands -- with few exceptions, each species on an island has a match on the other islands," Mahler said.

By combining the body-form data with a family tree of the Anoles, Mahler and colleagues were able to construct an "adaptive landscape" for the lizards. An adaptive landscape is a fundamental concept in evolutionary biology but difficult to show in practice. Peaks on an adaptive landscape represent various combinations of features that will be favored by natural selection, whereas valleys are just the opposite. Species with similar habits will tend to cluster on the same peak.

For Anole lizards, their niche might be living on tree-trunks, or among twigs high in a tree, or down in the grasses on the ground. Each calls for different adaptations, and creates a different adaptive peak.

Read more at Science Daily

Unearthed Mayan Tablet Tells of Power Struggle

A nearly 1,500-year-old Mayan stone monument, inscribed with a story of an ancient power struggle, has been unearthed in Guatemala.

The stone slab, which dates to A.D. 564, was found in a small tunnel that adjoins the tomb of an ancient queen beneath the Mayan temple at the site of El Perú-Waka'.

The slab, almost 6 feet (2 meters) high and 3 feet (1 m) wide, is carved with the image of a large man in its center, and is inscribed with Mayan hieroglyphics. The text on the monument describes a tumultuous seven-year period when two dynasties battled for rule of the ancient kingdom.

Prior to discovering this monument, no one knew the names of Mayan rulers during the sixth century.

"It really does advance our knowledge of the history of this royal family and dynasty," said study co-author David Friedel, an anthropologist at Washington University in St. Louis.

Ancient empire

The Mayan empire flourished in southern Mexico and parts of Guatemala for about six centuries, then mysteriously collapsed around A.D. 900. The Mayans built the massive city of Tikal, developed a hieroglyphic writing system and their own calendar, which infamously predicted the world would end in 2012.

However, because they usually wrote on paper, rather than stone, "most of their writing is gone," Friedel told LiveScience.

Earlier this year, Friedel and his colleagues were excavating the Mayan tomb of a royal woman named Lady K'abel, when they uncovered the massive stone stele. Carved into the stele was the outline of a man cradling a sacred bundle in his arms, and there were inscriptions describing his feats on the sides of the monument.

Though the stone was worn away in the center, the inscriptions on the side remained readable.

Tumultuous period

The team deciphered the inscriptions to reveal that a king known as King Wa'oom Uch'ab Tzi'kin, or He Who Stands Up the Offering of the Eagle, likely dedicated the stele to his father, King Chak Took Ich'aak, or Red Spark Claw, in 564. Both names were lost to history until now.

Because the Mayan calendar date was written on the slab, the team knows the exact day on which it was dedicated.

The inscription reveals that the death of the father, King Chak Took Ich'aak, in A.D. 556 ushered in a period of political turmoil as different groups grappled for supremacy.  His son ultimately took the throne.

Read more at Discovery News

Fossilized Elephant Tusk Found on Seafloor

A fossilized elephant tusk at least 100,000 years old has been discovered on the seafloor off the Sicilian coast, according to a survey of underwater archaeologists.

Discovered during a series of archaeological dives in the waters off Torretta Granitola, a village on the island’s southwestern coast, the tusk is more than 3 feet long.

“It was found embedded on the sea bottom in Pleistocene alluvional deposits,” the Superintendency of Maritime Cultural Heritage of Sicily said in a statement.

In the same area, Giampaolo Mirabile, a local diver, found some years ago two molar teeth belonging to the dwarf elephant Palaeoloxodon mnaidriensis, or Elephas Mnaidriensis, a species that roamed Sicily between 100,000 and 200,000 years ago.

“The tusk’ size confirms the previous finding and points to the same extinct species,” Sebastiano Tusa, Sicily’s superintendent of the Sea Office, said.

Tusa, who dived to the site with Giampaolo Mirabile, Gaetano Lino and Alessandro Urbano, also noticed what appeared like elephant footprints near the tusk.

“It’s clear now that the elephant’s disarticulated remains are spread in a limited area, embedded in a pebble conglomerate which is the result of alluvional deposits,” Tusa said.

Not far from the fossil find, the archaeologist also discovered numerous lumps of flint. Since the flints lay at a depth of about 13 feet, it is possible they represents the remains of a ship and its cargo.

But there might be a more likely explanation.

“Flint was used in the manufacture of tools since the most remote prehistory, mostly in Paleolithic and Neolithic times,” Tusa said.

Read more at Discovery News

Snow's Up! Frosted Star System Discovered

When you look at a snow-capped mountain, the line that separates the snow-less lower slopes and the snowy peak is descriptively known as a “snow line.” It’s above this line where you’d want to go with your snowboard or skis. Now, for the first time, astronomers have discovered the snow line for a particularly frosty star system 175 light-years away — but there’s no word on the quality of the snow for slaloming.

Stellar snow lines work in a similar way to their terrestrial mountain counterparts. On a mountain, there’s a certain altitude where the atmosphere becomes so cold that water will freeze and snow will collect around the frozen mountain peak. Around a star, on the other hand, there’s a certain distance from the hot star where it becomes so cold that it allows water (and other volatiles, such as methane) to freeze as ice particles.

Astronomers using the brand new Atacama Large Millimeter/submillimeter Array (ALMA) in Chile have used a neat little trick to resolve the stellar snow line around the young sun-like star TW Hydrae. And by doing so, they have taken a glimpse at what our solar system may have looked like during the early stages of its evolution.

“ALMA has given us the first real picture of a snow line around a young star, which is extremely exciting because of what it tells us about the very early period in the history of the Solar System,” said Charlie Qi of the Harvard-Smithsonian Center for Astrophysics, one of the two lead investigators of this study. “We can now see previously hidden details about the frozen outer reaches of another planetary system similar to our own.”

An added bonus to observing the snow line around another star is that it can give us a sense as to how planets, comets and even organic molecules may form.

Water (H2O) is the first molecule to condense and freeze when it reaches the necessary distance from the star, forming the first snow line. Moving further away from a star, other molecules start to freeze, such as carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO). As each species of molecule has a different freezing point, the snow line of each can be found at different distances from the star.

In the case of our solar system, the formation of the planets may have been influenced by the different snow lines at different orbital distances from the sun. During the protoplanetary phase of the sun, frozen volatiles at certain snow lines would have given the protoplanetary dust a sticky outer layer, potentially accelerating planet formation through the process of agglomeration. For example, the water snow line for the sun can be found between the orbits of Mars and Jupiter; the CO snow line is at the orbit of Neptune. How does this factor into planetary formation at those distances?

The CO snow line is also interesting, say Qi and his team, for its implication in the formation of methanol, one of the key ingredients for organic chemistry. If comets formed beyond the solar system’s CO snow line, they could have been enriched in organic compounds that were then transported to the inner solar system, depositing the life-giving cocktail on Earth. We could be witnessing this process unfolding around TW Hydrae.

But seeing the CO snow line isn’t easy — CO cannot be observed directly. So, the team hunted down the fragile, yet easily identifiable diazenylium (N2H+) molecule that generates a strong and identifiable millimeter wavelength emission that is perfect for ALMA to detect. N2H+’s chemistry is easily broken down by the presence of CO. So, through a simple astronomical process of elimination, where N2H+ isn’t, CO is. By seeking out the absence of N2H+, they’d created a negative picture of the location of the CO’s snow point around the star.

Read more at Discovery News

Jul 18, 2013

Microbes Can Influence Evolution of Their Hosts

You are not just yourself. You are also the thousands of microbes that you carry. In fact, they represent an invisible majority that may be more you than you realize.

These microscopic fellow travelers are collectively called the microbiome. Realization that every species of plant and animal is accompanied by a distinctive microbiome is old news. But evidence of the impact that these microbes have on their hosts continues to grow rapidly in areas ranging from brain development to digestion to defense against infection to producing bodily odors.

Now, contrary to current scientific understanding, it also appears that our microbial companions play an important role in evolution. A new study, published online on July 18 by the journal Science, has provided direct evidence that these microbes can contribute to the origin of new species by reducing the viability of hybrids produced between males and females of different species.

This study provides the strongest evidence to date for the controversial hologenomic theory of evolution, which proposes that the object of Darwin's natural selection is not just the individual organism as he proposed, but the organism plus its associated microbial community. (The hologenome encompasses the genome of the host and the genomes of its microscopic symbiotes.)

"It was a high-risk proposition. The expectation in the field was that the origin of species is principally driven by genetic changes in the nucleus. Our study demonstrates that both the nuclear genome and the microbiome must be considered in a unified framework of speciation," said Associate Professor of Biological Sciences Seth Bordenstein who performed the study with post-doctoral fellow Robert Brucker.

They conducted their research using three species of the jewel wasp Nasonia. These tiny, match-head sized wasps parasitize blowflies and other pest flies, which make them useful for biological control.

"The wasps have a microbiome of 96 different groups of microorganisms," said Brucker. Two of the species they used (N. giraulti and N. longicornis) only diverged about 400,000 years ago so they are closely related genetically. This closeness is also reflected in their microbiomes, which are quite similar. The third species (N. vitripennis), on the other hand, diverged about a million years ago so there are greater differences in both its genome and microbiome, he explained.

The mortality of hybrid offspring from the two closely related species was relatively low, about 8 percent, while the mortality rate of hybrid offspring between either of them and N. vitripennis was quite high, better than 90 percent, the researchers established.

"The microbiomes of viable hybrids looked extremely similar to those of their parents, but the microbiomes of those that did not survive looked chaotic and totally different," Brucker reported.

The researchers showed that the incompatibilities that were killing the hybrids had a microbial basis by raising the wasps in a microbe-free environment. They were surprised to find that the germ-free hybrids survived just as well as purebred larvae. But when they gave the germ-free hybrids gut microbes from regular hybrids, their survival rate plummeted.

Read more at Science Daily

Climate Change 10,000 Times Faster Than Evolution

Evolution can be fast, but not fast enough to keep up with the rate of human-caused climate change, say two researchers who have studied the evolution rates of hundreds of species in the past.

In fact, many vertebrate species would have to speed up their evolution rate 10,000 times to match today's pedal-to-the-metal rate of global warming, according to John Wiens, an ecology and evolutionary biology professor at the University of Arizona, and Ignacio Quintero, a postgraduate research assistant at Yale University.

"A big question is 'Can some species adapt quickly enough to survive?'" said Wiens. “So we looked at 17 groups of animals” comprising 540 species that included amphibians, birds, reptile and mammals, to see how they adapted to temperature changes in the past. “We estimated the rate of climate change for these species.”

Specifically, they looked at when these species split into new species based on genetic data, which is a measure of their rate of evolution, and compared that to climate changes in the niches where those animals lived at those same times in geological history. What they found was that the species could handle a global temperature change of about one degree centigrade per million years. Their results appear in a paper in the latest issue of the journal Ecology Letters.

The problem, of course, is that humans are un-sequestering and burning millions of years worth of carbon-rich fossil fuels and releasing their heat-retaining gases into the atmosphere at a rate that's causing a temperature rise of perhaps 4 degrees Celsius by the year 2100. So if a species can't move to a nearby cooler habitat, it will be unlikely to evolve out of its predicament and survive.

All this seems to fly in the face of a variety of special cases of rapid evolution that have been documented in birds, reptiles and amphibians. But that's not quite so, explained evolutionary biologist Robert Holt of the University of Florida.

The rate of evolution of a particular group of animals probably has a lot to do with how big of a genetic tools, or flexibility to develop new traits, a species has to work with. Some species have more than others, Holt said.

“There is a lot of rapid evolution in the world as well as a lot of animals that don't evolve when you thought they would,” said Holt. Horseshoe crabs, for instance, haven't changed much in 300 million years, he said. But their ecological niche hasn't changed much either. So evolutionary “stasis” is key to that animal's survival.

But the same talent for not evolving could be a serious liability for a species being directly affected by rapid climate change – like a bird, reptile or amphibian, for instance. And even those species that are more capable of changing may not always make it.

“Even if they have the genetic variation, it may not be enough,” said Holt. “The rate of population decline may still be so much that they can't avoid extinction.” This is especially true of species that are already small in numbers, he said.

Read more at Discovery News

Largest Viruses Ever Revealed

Giant viruses, more than twice as big as the last largest known viruses, have now been unearthed from sludge across the world, researchers say.

Even more titanic viruses might await discovery, the scientists said, and they may have features that could blur the lines between life and viruses, which are not considered to be living things.

Ten years ago, researchers accidentally discovered mimivirus, what until now was the biggest, most complex virus known. Mimivirus is a name derived from "mimicking microbes." The name was chosen because the viruses were nearly the size of some bacteria. Its relatives the megaviruses can reach sizes of more than 700 nanometers (a nanometer is one billionth of a meter) and possess more than 1,000 genes, features typical of parasitic bacteria. Typical viruses are maybe 20 to 300 nanometers large, and  many viruses, such as influenza or HIV, get along very well with 10 or fewer genes.

Now the research team that discovered those giant viruses have unearthed two more that are even bigger. The shape of these new viruses, which resemble ancient Greek jars, reminded the scientists of the myth of Pandora's box, giving the germs their name -- pandoraviruses.

"The opening of the box will definitively break the foundations of what we thought viruses were," Chantal Abergel, research director at the French National Center for Scientific Research in Marseille, told LiveScience.

The new record-breaking viruses are visible with a traditional light microscope, being a full micrometer or millionth of a meter in size, or approximately a hundredth the width of a human hair. They also each possess a whopping roughly 2,500 genes.

"We were prepared to find new viruses in the 1,000-gene range, but not to more than double that figure," Abergel said. "This really indicates than we don't know what are the possible limits anymore."

Megaviruses, which initially were mistaken for bacteria, were discovered in amoebas, and the investigators found pandoraviruses by also looking at amoebas. One virus, named Pandoravirus salinus, was unearthed at the mouth of the Tunquen River off the coast of central Chile, while the other, called Pandoravirus dulcis, dwelled at the bottom of a shallow freshwater pond near Melbourne, Australia. (Pandoravirus-like particles were actually first observed about 13 years ago, but were not recognized as viruses at the time.)

Two to four hours after amoebas engulf these pandoraviruses, the nucleus of the amoebas begins transforming radically, ultimately vanishing. When the amoebas finally die, they each unleash about 100 pandoraviruses.

The amoebas the researchers used in their experiments are probably not the natural hosts for these viruses; rather, the main targets of these viruses may be protozoa or algae that are typically very difficult to grow and maintain in labs.

The scientists used amoebas instead because they can grow in labs, and gorge on their surroundings in a very indiscriminate way, sweeping most anything into themselves as they look for potential food. "This is why they are a very good target for capturing giant viruses," Abergel said.

More than 93 percent of pandoravirus genes resemble nothing known. This makes their origins a mystery — analysis of their genomes suggests pandoraviruses are not related to any known virus family.

"These viruses have more than 2,000 new genes coding for proteins and enzymes that do unknown things," Abergel said. "Elucidating their biochemical and regulatory functions might be of tremendous interest for biotech and biomedical applications. We want to propose a full large-scale functional genomics project on the pandoravirus genomes."

The fact that pandoraviruses are totally different from the previously known family of giant viruses may suggest even more families of giant viruses remain to be discovered, said researcher Jean-Michel Claverie, head of the Structural and Genomic Information Laboratory in Marseille, France.

"Our knowledge of the microbial biodiversity on this planet is still very partial," Claverie said. "Huge discoveries remain to be made at the most fundamental level that may change our present scenario about the origin of life and its evolution."

It remains a mystery why pandoraviruses have more than 2,500 genes while most viruseshave far less, the researchers said. One controversial suggestion the researchers make is that giant viruses and other viruses that depend on DNA as their genetic material may be the shrunken descendants of living, cellular ancestors.

Read more at Discovery News

Mars' Once Thick Atmosphere Now Kaput

At one time, Mars had a thick, protective atmosphere -- possibly even cushier than Earth’s -- but the bubble of gases mostly dissipated about 4 billion years ago and has never been replenished, new research shows.

The findings come from NASA’s Mars rover Curiosity, which has been moonlighting as an atmospheric probe as it scours planet’s surface for habitats that could have supported ancient microbial life. The rover landed inside a large impact basin called Gale Crater last August.

Two instruments aboard Curiosity are providing scientists with unprecedented details about Mars’ present-day atmosphere. The data is then run through computer models as well as compared to analysis of trapped gases in ancient Mars meteorites that have been recovered on Earth.

The scientists look for telltale isotopes, which are atoms of elements that have different numbers of neutrons. Normal carbon, for example, is known as carbon-12 and contains six neutrons. Some carbon stragglers may have seven, or even eight, neutrons. What’s key is how the isotopic concentrations change over time.

Across all the gases in Mars’ atmosphere -- carbon dioxide, argon, nitrogen, oxygen and carbon monoxide -- scientists found higher concentrations of isotopes, evidence that most of the atmospheric gas has escaped.

“The overarching conclusion is that the Mars atmosphere hasn’t really changed a lot in 4 billion years,” said Chris Webster, manager of the Planetary Sciences Instruments Office at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

Why the planet lost its atmosphere is a matter of debate, but scientists believe it stemmed from the loss of the planet’s magnetic field.

“On Earth, our magnetic field protects us, it shields us from the solar wind particles. Without Earth’s magnetic field, we would have no atmosphere and there would be no life on this planet. Everything would be wiped out -- especially when you go back 4 billion years. The solar wind was at least 100 times stronger then than it is today. It was a young sun with a very intense radiation, ” Webster told Discovery News.

That might be exactly what happened on Mars, though whether life could have evolved and been preserved are key questions being addressed by Curiosity and the focus of follow-on missions now in the planning stages.

“The jury is out on how long an earlier, heavy atmosphere might have persisted after the late heavy bombardment, when things were flying around,” said NASA’s Paul Mahaffy, lead scientist for Curiosity’s Sample Analysis at Mars suite of instruments.

“Before that, the record is probably hard to find because things probably really got changed by all these impacts. But once things settled down a little bit, it’s a really important to understand what the climate conditions were,” Mahaffy told Discovery News.

Read more at Discovery News

Jul 17, 2013

Dogs Remember as Well as Humans

The memory of dogs is more human-like than previously thought, allowing our furry pals to copy our actions, even after delays.

The discovery, outlined in the latest issue of Animal Cognition, means that dogs possess what’s known as “declarative memory,” which refers to memories which can be consciously recalled, such as facts or knowledge.

Humans, of course, have this ability, as anyone playing a trivia game demonstrates. But it had never fully been scientifically proven in dogs before, although dog owners and canine aficionados have likely witnessed the skill first-hand for years.

Claudia Fugazza and Adám Miklósi of Eötvös Loránd University in Hungary conducted the study. A LOT of dog studies happen in Hungary, where people really love their pooches and some of the world’s leading canine researchers live.

The team investigated if dogs could defer imitation, which in this case meant copying what their owners were doing. Eight adult pet dogs were trained using the “Do As I Do” method. (Fugazza is a leading expert on this training method for dogs.) The tasks included copying their owners walking around a bucket and ringing a bell. Can dogs then successfully replicate what they learned after a 10 or so minute distracting break?

Fugazza described what happened next with one owner-dog pair:

The owner, Valentina, got her dog Adila to pay attention to her. She then demonstrated an activity, like ringing a bell with her hand.

Valentina and Adila then took a break, with both doing whatever they wanted to do. Sometimes they played together with a ball, or relaxed on a lawn. Adila happily sniffed around and barked at passers by.

After the break, Valentina went to her original starting position and gave the command “Do it!” Adila knew exactly what came next. The attentive dog rang the bell. Adila even did this when a human stranger, who didn’t even know what the prior activity (bell ringing) was, gave the same command.

Read more at Discovery News

Flesh-Eating Worms Invade Woman's Ear

After the British tourist returned from a vacation in Peru earlier this year, she started experiencing headaches, shooting pains down the side of her face and an unexplained discharge from one ear.

Those symptoms, plus the bizarre scratching sounds she continued hearing, prompted Harris to visit a doctor soon after her return to England.

Though doctors at first dismissed the symptoms as nothing more than an ear infection, specialists soon made a startling discovery: Harris' ear was filled with flesh-eating worms, according to the Daily Mail.

The worms that Harris, 27, was hosting were the larvae of the New World screwworm fly (Cochliomyia hominivorax). The fly is a notorious livestock pest that also seeks out pets, zoo animals and occasionally humans as hosts.

A pregnant female screwworm fly seeks an open wound on the skin of a warm-blooded animal to lay her eggs. Within 24 hours, the eggs hatch into tiny larvae that feed on living tissue and bodily fluids, according to the Food and Agriculture Organization of the United Nations.

The screwworm fly was, after many years of eradication efforts, eliminated from the United States in 1959 by a program that introduced sterile males into the population. The fly, however, continues to plague livestock in parts of Central and South America.

A close relative, the secondary screwworm fly (Cochliomyia macellaria), feeds on dead or diseased flesh. The larvae of this fly have been used successfully in "maggot therapy" to clean infected wounds and promote healing after surgery.

Harris was apparently infected after a swarm of flies pestered her while hiking in Peru; one flew into her ear, but after she shooed the insect away, she thought nothing more of it.

Read more at Discovery News

Dino With Huge Nose and Horns Unearthed in Utah

A North American dinosaur with a large nose and gigantic horns was unearthed for the first time in the remote badlands of southern Utah, according to a new study.

The dinosaur, Nasuceratops titusi, aka “Big Nosed Horned Faced,” measured about 15 feet long and weighed about 2.75 tons. It lived approximately 76 million years ago and is described in the latest Proceedings of the Royal Society B.

Its huge nose remains a mystery.

“The jumbo-sized schnoz of Nasutoceratops likely had nothing to do with a heightened sense of smell — since olfactory receptors occur further back in the head, adjacent to the brain — and the function of this bizarre feature remains uncertain,” lead author Scott Sampson of the Denver Museum of Nature & Science, said in a press release.

What we do know is that this badass badlands dino lived in what was then a swampy, subtropical setting on the “island continent” of western North America, also known as Laramidia. This landmass formed when a shallow sea flooded the central region of North America, isolating the western and eastern portions for millions of years during the Late Cretaceous.

The dinosaur was a plant eater and belonged to the same family as Triceratops. Its horns indicate that it didn’t just stand around peacefully eating leaves, though.

“The amazing horns of Nasutoceratops were most likely used as visual signals of dominance and, when that wasn’t enough, as weapons for combatting rivals,” said co-author Mark Loewen of the Natural History Museum of Utah and the University of Utah.

Eric Lund of Ohio University discovered the news species.

Read more at Discovery News

Sharks Thrive in Fiji's Protected Waters

In Fiji's largest marine reserve, shark populations are benefiting from "no-take" protections that keep their food supply steady, according to a new study.

Compared with waters where fishing is allowed, there are up to four times as many reef sharks in a protected zone called the Namena Reserve, researchers say.

This 23-square-mile (60 square kilometers) reserve was designated in 1997 off the southern coast of Vanua Levu, Fiji's second largest island. For three weeks in July 2009, researchers used underwater video cameras to survey sharks at eight sites within Namena and eight sites outside the reserve.

Hour-long clips from all 16 locations captured images of five different species: grey reef sharks, whitetips, blacktips, silvertips and zebra sharks. By analyzing this footage, researchers found that shark abundance and biomass in the protected zone was twice as great at shallow sites and four times as great at deep sites, compared with similar spots just outside of the reserve.

Sharks are harvested for their meat, liver oil, cartilage and their famously valuable fins; these cartilaginous parts are hacked off, often from live sharks, to be used in shark fin soup, a prized delicacy in East Asia. Since sharks have slow growth and reproductive rates, it can be difficult for their populations to bounce back from big losses and unsustainable hunting practices. A study published earlier this year estimated that 100 million sharks are killed by fisheries each year.

In Fiji, tradition has kept shark harvesting in check. Many people in the island nation consider sharks to be sacred and see eating the predators as taboo, according to researchers with the Wildlife Conservation Society (WCS) who worked on the new study. Within the Namena Reserve, sharks likely are thriving because restrictions on fishing make their prey plentiful, the researchers say.

"The news from Fiji gives us solid proof that marine reserves can have positive effects on reef shark populations," Caleb McClennen, director of WCS's Marine Program, said in a statement last week. "Shark populations are declining worldwide due to the demand for shark products, particularly fins for the Asian markets. We need to establish management strategies that will protect these ancient predators and the ecosystems they inhabit."

Sharks in Fiji may still be vulnerable to foreign fishing fleets, the researchers warn, and local communities may be driven to hunt the venerated animals as prices for shark parts increase. According to the World Wildlife Fund, a shark's fin can sell for up to $135 per kilogram (about 2 lbs) in Hong Kong.

Read more at Discovery News

Jul 16, 2013

T. Rex Was Ferocious Predator, Not Scavenger

As most anyone who went through the "dinosaur phase" in childhood already guessed Tyrannosaurus rex was a fearsome predator.

A plant-eating dinosaur found with a Tyrannosaurus rex tooth lodged in its tail has confirmed what scientists long suspected: T. rex was a predator.

The tooth was discovered in the tail of a hadrosaur that lived about 66 million years ago.

"It's the Holy Grail for a paleontologist," said study co-author David Burnham, a paleontologist at the University of Kansas. "Not only was the tooth broken off, but the tail had healed around it. That means that Tyrannosaurus rex attacked that other dinosaur."

The findings were published today (July 15) in the journal Proceedings of the National Academy of Sciences.

Circumstantial evidence

Although T. rex has been portrayed as the deadliest dino predator, the case for predation wasn't airtight. Even though stomach remains, a fearsome bite and body plan all suggested the imposing dinosaur attacked and ate other prey, some paleontologists proposed that T. rex was a scavenger, feasting on already dead animals but not killing its prey itself.

A few other herbivore fossils had been found with traces of T. rex bite wounds, but the evidence wasn't conclusive.

Burnham and his colleagues were excavating in the Hell Creek formation in South Dakota. During the Cretaceous Period, the area was a vast network of forested rivers, and the formation now contains myriad fossils of dinosaurs and small mammals from the period.

'Beyond a reasonable doubt'

Burnham's graduate student, Robert DePalma, uncovered two fused vertebrae from the tail of a hadrosaur, likely Edmontosaurus annectens, a plant eater that munched on pine needles using scissorlike teeth.

Lodged inside the vertebrae was part of a tooth, and the area around it showed signs of healing. When the team analyzed the serrations on the tooth, they confirmed it belonged to a T. rex.

Read more at Discovery News

Long-Lost Pyramids Found?

Mysterious, pyramid-like structures spotted in the Egyptian desert by an amateur satellite archaeologist might be long-lost pyramids after all, according to a new investigation into the enigmatic mounds.

Angela Micol, who last year found the structures using Google Earth 5,000 miles away in North Carolina, says puzzling features have been uncovered during a preliminary ground proofing expedition, revealing cavities and shafts.

"Moreover, it has emerged these formations are labeled as pyramids on several old and rare maps," Micol told Discovery News.

Located about 90 miles apart, the two possible pyramid complexes appeared as groupings of mounds in curious positions.

One site in Upper Egypt, just 12 miles from the city of Abu Sidhum along the Nile, featured four mounds with an unusual footprint.

Some 90 miles north near the Fayum oasis, the second possible pyramid complex revealed a four-sided, truncated mound approximately 150 feet wide and three smaller mounds in a diagonal alignment.

"The images speak for themselves," Micol said when she first announced her findings. "It's very obvious what the sites may contain, but field research is needed to verify they are, in fact, pyramids,"

First reported by Discovery News, her claim gained widespread media attention and much criticism.

Authoritative geologists and geo-archaeologists were largely skeptical and dismissed what Micol called "Google Earth anomalies" as windswept natural rock formations -- buttes quite common in the Egyptian desert.

"After the buzz simmered down, I was contacted by an Egyptian couple who claimed to have important historical references for both sites," Micol said.

The couple, Medhat Kamal El-Kady, former ambassador to the Sultanate of Oman, and his wife Haidy Farouk Abdel-Hamid, a lawyer, former counselor at the Egyptian presidency and adviser of border issues and international issues of sovereignty, are top collectors of maps, old documents, books and rare political and historical manuscripts.

El-Kady and Farouk have made important donations to the Egyptian state and the U.S. Library of Congress. Their various gifts to the Library of Alexandria include Al-Sharif Al-Idrissi's map of the Earth drawn for King Roger II of Sicily in 1154.

According to the couple, the formations spotted by Micol in the Fayum and near Abu Sidhum were both labeled as pyramid complex sites in several old maps and documents.

"For this case only, we have more than 34 maps and 12 old documents, mostly by scientists and senior officials of irrigation," El-Kady and Farouk told Discovery News.

For the site near the Fayum, they cited three maps in particular -- a map by Robert de Vaugoudy, dating from 1753, a rare map by the engineers of Napoleon Bonaparte, and a map and documents by Major Brown, general of irrigation for Lower Egypt in the late 1880s.

The documents would point to the existence of two buried pyramids which add to the known Fayum pyramids of Lahoun and Hawara.

"They would be the greatest pyramids known to mankind," the couple said. "We would not exaggerate if we said the finding can overshadow the Pyramids of Giza."

Their sources would indicate the pyramids at the Fayum site were intentionally buried in a "damnatio memoriae" -- an attempt to intentionally strike them from memory.

While the site in the Fayum has not been investigated yet, a preliminary on-the-ground expedition has already occurred at the site near Abu Sidhum, providing intriguing data to compare with El-Kady and Farouk’s maps and documents.

"Those mounds are definitely hiding an ancient site below them," Mohamed Aly Soliman, who led the preliminary expedition near Abu Sidhum, told Discovery News.

"First of all, the land around them is just a normal flat land. It is just desert -- sand and stones," he said. "The mounds are different: You will find pottery everywhere, seashells and transported layers. These are different layers, not belonging to the place, and were used by the Egyptians to hide and protect their buried sites," he said.

"Describing himself as "one of the many Egyptians obsessed with the pharaohs’ civilization," Aly has a background as a private investigator and has been studying to identify archaeological sites in Egypt.

"If we look back in history we will find that pharaohs were using seashells in building their tombs and pyramids for ventilation purpose," Aly said.

"Even the rocks used in building pyramids contained up to 40 percent seashells."

Read more at Discovery News

TICKS: Outdoor Enemies or Harmless Arachnids?

While outdoor enthusiasts plan a host of activities this time of year, many live in fear of one tiny arachnid – the tick. According to experts who study these minute creatures, that fear is often unfounded, and there are definite steps to take to avoid coming in contact.

“This is the time of year when certain areas become tick habitats,” said Glen Scoles, a research entomologist for the Agricultural Research Service of the USDA at the Animal Disease Research Unit in Pullman, WA. “Foresty areas are prone to this, and these days many people choose to live in suburbs close to infested areas. Different parts of the country deal with different types of ticks and diseases related to ticks.”

In the Western United States where Scoles lives, American dog ticks and Rocky Mountain wood ticks are common, some of which can transmit diseases. The latter even accounts for some cases of tick paralysis, said Scoles. “This is a situation where the tick’s saliva causes a response in humans that leads to paralysis, causing people not to be able to use their legs, and as the paralysis creeps upward it can reach the diaphragm and lead to death. However, if the tick is removed properly, the symptoms disappear.”

In the Eastern United States, ticks are commonly connected to Lyme disease, which in early stages can be treated with antibiotics, but if caught too late can lead to debilitating conditions. Recently, black-legged ticks have been associated with cases of encephalitis in New York state.

The Centers for Disease Control and Prevention (CDC) suggests two highly effective ways to avoid coming in contact with ticks. First, the CDC recommends using products containing permethrin to treat clothing and outdoor gear. Permethrin is a synthetic chemical that works as both an insecticide and insect repellent. Permethrin should never be used directly on the skin. Further, the CDC recommends using a product with 20 percent or more DEET, which is an oil applied to the skin that provides protection against biting insects, including ticks.

Permethrin has been in use for decades, and these days is even used to treat military uniforms. The chemical has a history of effectiveness with few side effects or dangers, according to Dr. Kirby C. Stafford III, head of the Department of Entomology at The Connecticut Agricultural Experiment and state entomologist for Connecticut.

“Permethrin was one of the first synthetic insecticides that was discovered and has very low toxicity,” Stafford said. “Today it’s used in a wide variety of products in relation to ticks in two ways; first as an ingredient in clothing-based tick repellents, and second as an insecticide for ground application to control ticks.”

According to Scoles, who has studied ticks for 17 years, the good news is that the widespread fear and cringing associated with ticks is often much ado about nothing.

“Ticks are a part of the natural biology of the world,” Scoles said. “It is important for people to know that every tick that bites you is not carrying some deadly disease. In fact, there is only a one to two percent chance the tick that bites you is going to transmit anything to you. Sometimes people get swollen lymph nodes or severe itching and swelling at the site of the bite, but the symptoms go away. You do not have to assume that all reactions are due to bacteria.”

Read more at Discovery News

People May Get Place in Geologic Time Scale

The Anthropocene is the name of a proposed new geological time period (probably an epoch) that may soon enter the official Geologic Time Scale. The Anthropocene is defined by the human influence on Earth, where we have become a geological force shaping the global landscape and evolution of our planet.

According to this idea, the present epoch — still known as the Holocene, which started 11,000 years ago — would have ended somewhere between the end of 18th century and the 1950s (when the Anthropocene began). The earlier time limit considers the increasing amount of carbon dioxide and other greenhouse gases in Earth’s atmosphere that is mostly due to the burning of fossil fuels for energy to power our growing industrial technology.

We may consider this process to have started in 1784, with the invention of the steam engine by James Watt. The present high levels of greenhouse gases in our atmosphere are probably causing global warming. The later time period takes into account the increasing background radiation from the nuclear tests by the United States and the Soviet Union during the beginning of the Cold War.

This new frontier in the geological timeline is potentially more precisely defined than any was before due to its recent occurrence. The Antrhopocene is also supported by increasing evidence of human influence on natural global processes, such as the sediment transport being supplanted by our construction processes; land occupation and transformation; water course deviation and water reserve appropriation; massive extinction and introduction of invasive species; development and widespread use of previously non-existent chemical substances (eg. plastics and persistent organic pollutants); and even the creation of new elements (the last 20 in the periodic table).

In this interview, Dr. David Grinspoon, Baruch S. Blumberg Chair of Astrobiology at the Library of Congress and Curator of Astrobiology at the Denver Museum of Nature & Science, talks about a book he is writing on the Anthropocene from an astrobiology point of view.

Q: The Anthropocene concept has been slowly emerging in science due to comments from Antonio Stoppani in 1873 (Anthropozoic era), LeConte in 1879 (Psychozoic), Pavlov in 1922 (Anthropogene) and Vernadsky in 1962 (Noosphere). Eugene Stoermer and Paul Crutzen formally addressed the concept and introduced the Anthropocene term in the title of a paper for the Global Change Newsletter in 2000. Could you tell us when and how you got involved with the topic?

David Grinspoon: It’s a topic I’ve long been interested in. Even as a kid enthralled with science fiction, I wondered about the role of people in the long-term evolution of the Earth, the far future and the fate of humanity. And thinking about advanced life elsewhere in the universe also leads us back to wonder about how long a civilization can last, which raises the same questions.

In my PhD thesis, written in 1989, I discussed the fact that when a civilization develops the technology to prevent catastrophic asteroid impacts, it marks a significant moment in the evolution of the planet. And the book I’m writing now I actually started even before I finished my last book in 2003. It’s a natural sequel because in the end of that book I speculate about what the coming of "intelligence" and "civilization" mean for Earth and other planets.

So even though "Anthropocene" is a recently popular term for this concept, I’ve been thinking and writing about it for over 20 years. I’m so happy that it’s becoming such a central topic of discussion in the worlds of science, policy and environmental activism. It’s about time!

Q: What should be considered the geological marks of the Anthropocene?

DG: There are a number of reasonable suggestions for this, but my favorite is the signature of the first atomic bomb tests. This produces a signature, both isotopic and in terms of new geological structures, that cannot be interpreted in any other way. And the symbolism is so potent — the moment we grasped that terrible promethean fire that, uncontrolled, could consume the world.

Now, it’s true that humans were altering the Earth before this time, as several scientists have pointed out — for example, land use, agriculture, urbanization and atmospheric carbon dioxide. But, you know, other species have come along and changed the world before and we don’t name a geological epoch after each of them.

What is really different now is that we are aware of our world changing role. Or potentially aware — some of us are at least. So for me, regardless of how you define the Anthropocene, this is when it gets interesting — when the mass of humanity starts to wake up to our world-changing role. And after the Bomb, certainly after Hiroshima, we could not see ourselves, with our world-changing technology, the same again.

Q: How likely is the possibility that we are now living through the planet's sixth mass extinction event? Is it already big enough to be detected in a future paleontology effort using our present methods and capabilities of investigation?

DG: I have heard differing opinions on whether or not the sixth great extinction is assured at this point, but either way it is obvious we are having a significant impact on the evolution of life on this planet and many species have not, will not, survive our presence here. Our impact will be detectable for the rest of time on this planet.

For example, it is clear that the existing coral reefs on the planet will not survive our impact. We are going to lose them. This is inevitable now because of ocean acidification even in the best-case scenario.

It is slightly comforting that the reefs have disappeared before, due to past episodes of acidification, and they have returned. So they may be back in the future, but there will be a time of no coral reefs in Earth history that will forever be traceable to the actions we are taking now.

Q: Do you believe the Anthropocene should be classified as a new geological epoch within the Quaternary period, or does it stand for a larger time scale? Might the establishment of the Anthropocene geological time period include the presently known Holocene epoch?

DG: One interesting question about the Anthropocene is how long it might last. Geologically, will it be an event like the K/T boundary (which marks the extinction of the dinosaurs 65 million years ago), an epoch like the Paleocene or a transition like the origin of life?

I think it will either be a brief event recording the failed experiment of our so-called civilization, or it will be a transition to an entirely new planet in which intelligent life has a permanent role in managing the planet. But if we call it an epoch it represents an ambition for our species that is somewhere between these two extremes, and maybe that is OK for now.

Q: How do you rate the chances that the Anthropocene Study Group — established in June of 2009 — can convince the International Commission on Stratigraphy (ICS) in its 2016 meeting to add the Anthropocene epoch to the Geologic Time Scale?

DG: I don’t know. To be honest, I haven’t been following this too closely. It’s really not that interesting to me whether or not it becomes formally adopted as part of the geological time scale. What I’m interested in is the conversations going on about the Anthropocene and what it means to view ourselves as a part of Earth’s geological history. These conversations will continue regardless of what this Commission decides.

Read more at Discovery News

Jul 15, 2013

Educators Explore Innovative Theater as a Way to Learn Physics

In a study released last week, education researchers found that personifying energy allowed students to grapple with difficult ideas about how energy works. Contrasted with more traditional lectures and graphs, this innovative instructional technique may be useful for teaching about other ideas in physical science, which commonly deals with things that change form over time.

Energy is a very important concept across many fields of science, and is a key focus of the new national science standards. Energy is also a central player in several global issues, such as climate change and fuel economy. However, energy is a challenging concept to fully understand. While energy can be precisely defined mathematically, it is often difficult to grasp intuitively. Energy can change form -- a ball held at some height has energy due to the pull of gravity, which gradually becomes energy of motion as the ball falls. However, no energy is lost in the process, a property called "conservation of energy." These basic ideas may seem straightforward, but when applied to real world situations (like fuel economy), they become very challenging to think about.

"Existing representations [such as bar charts] don't emphasize the thing that we care most about energy in physics, which is that it's conserved," said lead author Rachel Scherr, of Seattle Pacific University. These other instructional methods also don't show how energy moves among different objects in a system.

In the current study, the researchers report their ongoing examination of an activity that they have created, called "Energy Theater." Energy Theater is specifically designed to help learners visualize energy and how it dynamically changes form and location. In Energy Theater, learners (K-12 science teachers in this study) each play the role of one "chunk" of energy, and indicate with hand gestures what form that energy has (e.g., chemical, motion, gravitational, thermal). Different objects are represented by loops of rope on the ground, and learners can move from object to object, demonstrating energy moving between those objects. While energy is not actually a material substance, this metaphor can help learners think about how a fixed amount of energy can flow between different objects.

For example, the group may be given the problem of, "Show what happens when a hand pushes a box across a table." Participants would first stand in the area representing the hand, making the gesture for "chemical energy." One by one, they would move to the area representing the box, changing their gesture to "energy of motion." Other scenarios might include how energy flows when an incandescent light bulb is turned on. The group must work together to decide how the "theater" will play out for a particular situation, making complicated decisions about just where and when the energy will flow and take different forms.

"These elaborate stories about energy dynamics are not usually told," said co-author Hunter Close of Texas State University. "In order to tell [these stories], we have to act them out, because they are so complicated." The authors note that the specific attributes of Energy Theater help support this deeper learning: "I think the important message is that diverse learners can figure out all kinds of sophisticated energy scenarios once they have a representation for doing so," said Scherr. Energy Theater automatically keeps track of how much energy is located in different places, emphasizing conservation. It also serves as a visual "memory" for the group, helping them to keep track of the different moving parts. "It's also kind of fun and enticing," said Scherr. "It's an opportunity to interact. It's easy to feel very involved in what the group is doing."

Current evidence for the effectiveness of the activity is that learners are able to generate very detailed energy tracking diagrams after the activity. Analysis of the groups' conversations as they work to script out the "play" also demonstrates the complexity of the ideas that the group is working to understand.

The team suggests that Energy Theater is a useful addition to more traditional instruction, enriching the student's development of ideas about energy. This approach might also be fruitfully applied to other areas of science involving dynamic processes -- for example, people might represent atoms in a substance, which can change state from solid to liquid to gas. The authors report that teachers typically appreciate the tactile nature of the activity, its appropriateness for English language learners, and the fact that all students have to participate.

Read more at Science Daily

Bilingual Children Have a Two-Tracked Mind

Adults learning a foreign language often need flash cards, tapes, and practice, practice, practice. Children, on the other hand, seem to pick up their native language out of thin air. The learning process is even more remarkable when two languages are involved.

In a study examining how bilingual children learn the two different sound systems of languages they are acquiring simultaneously, Ithaca College faculty member Skott Freedman has discovered insights that indicate children can learn two native languages as easily as they can learn one.

"At first glance, the process of learning a language can seem incredibly daunting," said Freedman, an assistant professor of speech language and pathology and audiology. "Environmental input presented at a fairly rapid rate must be mapped onto detailed representations in the brain. A word's meaning, sounds, and grammatical function all must be extracted from the incoming speech stream. Yet this potentially arduous task is typically executed with little effort by children barely a year old. In fact, studies show that children can learn a word in as little as one exposure."

But how complex is the process when a child grows up learning two languages?

"It has commonly been debated whether a bilingual child has one large set of sounds from both languages or, conversely, two separate sound systems," Freedman said. "A way of testing this theory is to measure a child's language productions in both languages using some measure of complexity and then comparing the two languages."

Freedman's study measured complexity in terms of the word shape, such as the presence of word-final consonants and consonant clusters. He also measured the degree to which the children could approximate their languages. For example, if a child said "tar" for the word "star," he or she produced three of four possible sounds, therefore approximating the word with 75 percent accuracy.

"A hypothesis proposed several years ago predicts that, though bilingual children may differ in their productions between languages, they will nevertheless maintain a similar level of overall approximation," Freedman said. "The hypothesis was confirmed in a study using an English-Hungarian bilingual child, but no study to date has tested the hypothesis in Spanish, the fastest-growing language in the United States."

Freedman's study compared the language productions of five English-Spanish bilingual children during a picture-naming task to the productions of five English-only and five Spanish-only speaking children. The results confirmed the hypothesis, with some added insights.

"While bilingual children produced more complex forms in Spanish than in English, they nonetheless approximated English and Spanish to the same degree. Perhaps while learning a language, some inner algorithm determines how much one needs to articulate in order to be understood regardless of the different kinds of sounds between languages. Otherwise, children should have been more easily understood in Spanish."

In addition, Freedman found that no production differences emerged between the bilingual children and their monolingual counterparts in English or Spanish, indicating a sufficient amount of independence between a bilingual child's two sound systems.

Read more at Science Daily

Big Lionfish Found at Disturbing Depths

The relentless scourge of lionfish has crept to unexpected depths: Off the coast of Florida, researchers say they found the venomous invader thriving around a sunken ship at 300 feet (91 meters) below the water's surface.

"We expected some populations of lionfish at that depth, but their numbers and size were a surprise," researcher Stephanie Green, of Oregon State University, said in a statement.

Last month, Green and colleagues investigated the seafloor near Fort Lauderdale, Fla., in a deep-diving Antipodes sub. At 300 feet (91 m) deep, the team witnessed a large number of the spiny fish near the intentionally sunken Bill Boyd cargo ship, an artificial reef created in 1986.

While lionfish are typically between 12 and 15 inches (30 to 38 centimeters) long, the Oregon State researchers say they saw unusually large specimens as big as 16 inches (40 cm) long.

"This was kind of an 'Ah hah!' moment," Green said. "It was immediately clear that this is a new frontier in the lionfish crisis, and that something is going to have to be done about it. Seeing it up-close really brought home the nature of the problem."

Native to tropical Indo-Pacific waters, lionfish were introduced to the Atlantic by humans in the 1990s, likely through the exotic pet trade. Now found in reefs from North Carolina to South America, the rapidly reproducing invasive fish have voracious appetites, gobbling up native fish and competing with other species for food resources.

Worse, lionfish have no natural enemies in Atlantic waters, except spear gun-toting humans. Another study, detailed online July 11 in the journal PLOS ONE, found that not even sharks can curb red lionfish populations in Caribbean reefs.

Researchers are trying to figure out what is keeping lionfish in check in the Pacific so that they might stem the Atlantic invasion, which thus far has looked to be unstoppable. Prepared correctly, lionfish are said to make a tasty meal, but one prick from the fish's venomous spine can cause excruciating pain. Lionfish derbies to bring in big catches of the predator have been held in Florida and the Caribbean.

Read more at Discovery News

The Best Way to Explore Europa? Bomb It

What’s the best way to explore Jupiter’s icy moon Europa? If tests by British scientists and engineers are anything to go by, bombing its icy crust with a heavy bullet-shaped penetrator should do the trick.

Europa holds significant promise as being a potential oasis for life in our solar system. Below its frozen, dirty surface, scientists know a liquid water ocean hides, protected from the ravages of space and heated by energy generated by gravitational interactions between the gas giant and moon. Forget the search for extinct microbes on Mars; some hypotheses hint at the potential for complex organisms evolving in Europa’s depths. And by “complex organisms,” we’re talking creatures potentially as complex as jellyfish.

The penetrator in flight during the ice impact test.
These ideas have recently been bolstered by some key discoveries that nutrients collecting on the icy surface are cycling into the ocean and oxygen levels in the Europan ocean could support a huge biomass. In short, the more we study Europa, the more it dares us to dive into its mysterious ocean, pushing us to seek out whatever lies beneath.

But there are huge challenges confronting any future manned or unmanned expedition to the Jovian moon. For one, the icy world has no atmosphere so mounting a surface mission would require a huge amount of energy to slow the lander safely; atmospheric breaking that slows Mars missions before landing simply does not exist on Europa. A Europa landing would have more in common with Apollo than Curiosity.

Also, to access the subsurface ocean, the mission would need some kind of novel drilling technique to drop a probe through the miles of icy crust. Either that, or we’d need to develop a strategy of landing a surface mission right next to a naturally-formed crevasse.

Now throw in the challenge of protecting your spacecraft from the ravages of Jupiter’s radiation belts and developing an energy source — likely nuclear — that will last for the duration of the mission and you have a beast of a proposition.

So, when a team of British engineers approached the idea of Europa exploration, they stripped the mission down to the basics. The Europa mission should consist, at least in part, of a high-velocity projectile that will use brute force to kick off exploration of this fascinating world.

Using a 10 ton block of ice and a 20 kilogram (44 lb) high-velocity penetrator, the team simulated impact velocities higher than what would occur if such a mission were chosen to explore Europa. At a rocket testing facility in Wales, they fired the bullet-shaped penetrator at 340 meters per second (760 miles per hour) — the speed of sound at sea level (on Earth) — into the ice block, decelerating at 24,000g. Sure, the penetrator turned the ice block into slush, but the key success was that the sensitive instrumentation inside the bullet survived intact. If this were a real “penetrator mission” to Europa, the bullet would have lodged itself deep inside the upper layers of the Europa ice, ready to do some science.

“It was really successful because the entry velocity was higher than expected and all the systems we’ve looked at so far have survived,” Marie-Claire Perkinson, the research program’s industrial leader from Astrium UK, told BBC News.

Now that tests are underway, the European Space Agency (ESA) is taking note.

“Penetrators offer a number of advantages over ‘soft landers’, which have to slow down to reach the surface safely,” explained ESA project manager Sanjay Vijendran. “They would enable you to get deep into the sub-surface essentially for free, up to three meters without having to drill. And being light means you can deploy a few at once from a single spacecraft orbiter.”

Read more at Discovery News

Jul 14, 2013

The Secret of Screaming Volcanoes Explained

Not far from Anchorage, Alaska, there is a volcano that screams. Then falls silent. Then erupts and throws volcanic ash 10 kilometers into the sky. Then starts all over and does it again, and again.

This strange and repeating seismic behavior was discovered in the 2009 eruptions of Redoubt Volcano by Alicia Hotovec-Ellis of the University of Washington. But now she and her colleagues have a model to explain what might cause all the screaming and then the silence before the volcanic storm.

To get an idea what the screaming sounds like – converted from seismic waves, sped up 60 times into audible sound waves – listen to this file which is a real recording of Redoubt Volcano. What you hear is a drum beat of quakes that get faster and faster until they blur together in a rising sound and then go quiet. It's the blurred rising sound that has been called the scream.

“You are getting 20 to 30 earthquakes a second,” said Stanford University seismologist Eric Dunham explaining how the screams are really harmonic seismic waves smearing together and becoming one big seismic sound. “Then you get 30 seconds of silence. Part of what we did was to try and figure out why.”

Dunham, Hotovec-Ellis and their colleagues published their model today in the journal Nature Geoscience. The model shows the rapid slipping of lots of small faults that have been identified underneath the volcano. The cause of the slipping is that they are near the conduits of molten, gassed-up rock that is super-pressurized and about to blow.

“It has to be close to the conduit because the pressure is incredibly high,” Dunham said of the calculated forces required to create both the scream and the silence.

The closest analogy Dunham has for what's happening is scratching fingernails on a slate chalkboard. By scratching slowly, the repeated slipping and catching of the nails creates a lot of noise. But if you press really hard and move your hand really fast, the horrible noise disappears as your fingers begin to glide over the board.

Similarly, in the high pressure just before the volcano erupts might be enough to speed up the quaking faults so that they slide more quickly and quietly, instead of slipping and halting.

Read more at Discovery News

Alien Probes Could Be Surfing the Galaxy

Computer simulations by a pair of researchers at the University of Edinburgh predict that a fleet of interstellar probes could explore the entire Milky Way galaxy within a fraction of the present age of Earth. This may seem like a tall order considering that our farthest interstellar spacecraft, Voyager 1, is still less than a light-day from Earth after being launched 36 years ago.

In the new simulation, however, alien probes only need to travel at 10 percent the speed of light to survey the entire galaxy within 10 million years. And, they could get a turbo-boost and save fuel by doing a slingshot off the gravitational fields of stars.

The concept of self-aware and self-replicating probes traveling across the galaxy is nothing new, however; the idea goes as far back as 1960. It was promoted by SETI pioneer Ronald Bracewell as an alternative to listening for interstellar artificial radio signals. The idea of a machine capable of cloning itself goes back at least 100 years; mathematician John von Neumann detailed the operation of such a robot in 1949.

In a recent paper, Arwen Nicholson and Duncan Forgan take the idea a step further by exploring three different scenarios of probe behavior: using standard powered flight, using gravitational slingshot techniques around stars, and hop scotching star-by-star to get the maximum speed boost under slingshot trajectories.

Voyager 1 and 2 zipped across the solar system with a boost form bouncing like a pinball off the gravitational fields of the massive outer planets.

“From the scaling of the probes’ performance with star number, we conclude that a fleet of self-replicating probes can indeed explore the galaxy in a sufficiently short time to warrant the existence of the Fermi Paradox,” the team reports.

The Fermi Paradox — where nuclear physicist Enrico Fermi asked the rhetorical question “where are they?” (extraterrestrials) — ponders why we have no evidence of alien visitations. For the UFO buffs, let me flatly say this does not mean pointy-eared aliens should be here and now, but instead suggests occasional visits over geologic time by virtually immortal robots.

The team’s simulations mean that our solar system should have been visited — perhaps more than once — well-before the dawn of man. Their alien builders might have been motivated to have the machines go stealthy and cover their tracks once a planetary system survey is completed.

In Arthur C. Clarke’s 1972 novel, Rendezvous With Rama, star-hopping aliens are pretty blatant. A giant cylindrical space ark enters the solar system. An astronaut survey team explores its dark, ghostly, interior hibernating city. Humans finally realize that the mothership is not stopping for a visit, but simply using the sun’s gravity to get a boot to destinations unknown.

Rama aside, don’t look for ‘spent’ or destroyed probes because visiting robots might definitely go green by not leaving behind any trash from their sorties. They would also have ability to self-repair during long interstellar voyages, and self-replicate with the ultimate 3D printer.

In a sprint across the galaxy a civilization may send out a few probes that would be programmed to choose the next star they travel to according to some decision-making algorithm. Once they reach the new star system, they scan for signs of life, and create a copy of themselves. The parent and child probe each pick a new star to travel to, and the process repeats itself in a geometric progression.

This scenario is compounded by the fact there could very likely be more than one fleet of probes from different extraterrestrial civilizations plying the galaxy. What if they run into each other? A purely sci-fi inspired scenario is where mutated probes abandon their original mission and start to prey on normal probes!

Such an interstellar fox and rabbit chase would greatly increase the exploration time and reduce the number of visits to our solar system, say the researchers. In the new simulation the exploration probes are continuously traveling at maximum speed and constantly dispersing radially across the galaxy. Predators would have a hard time catching their prey.

Equally problematic is the dilemma of how a fleet of probes stays in contact with one another so that they don’t duplicate efforts. Light travel delay times would squelch communication, unless superluminal contact has been achieved by something as exotic as quantum entanglement. Then all probes would know exactly where every other probe has been and is heading. Each probe could leave behind an omnidirectional beacon that emits a signal showing the star has been visited. Or probes could deposit a “captain’s log” for other probes to readout.

Ultimately the data collected by the entire fleet could be placed into a giant galactic archive. It would be a resource for all interstellar civilizations that are smart enough to find it, enter the correct password, and download survey data on many billions of star systems.

Read more at Discovery News