Jun 15, 2013

Teaching Complete Evolutionary Stories Increases Learning

Many students have difficulty understanding and explaining how evolution operates. In search of better ways to teach the subject, researchers at Michigan State University developed complete evolutionary case studies spanning the gamut from the molecular changes underlying an evolving characteristic to their genetic consequences and effects in populations. The researchers, Peter J. T. White, Merle K. Heidemann, and James J. Smith, then incorporated two of the scenarios into a cellular and molecular biology course taught to undergraduates at the university's Lyman Briggs College.

When the students' understanding was tested, the results showed that students who had understood an integrated evolutionary scenario were better at explaining and describing how evolution works in general.

The results of the research, described in the July issue of BioScience, are significant because evolution is not usually taught in this comprehensive, soup-to-nuts way. Rather, instructors teach examples of parts of the evolutionary process, such as the ecological effects of natural selection or the rules of genetic inheritance, separately. It appears that this fragmentation makes it harder for students to understand the process as a whole.

White and his colleagues note that "surprisingly few" comprehensive evolutionary study systems have been described, although the number is growing. The two employed in the BioScience study were about the evolution of sweet taste and wrinkled skin in domestic garden peas, and the evolution of light or dark coat color in beach mice living on light or dark sand. Students were tested on the beach mouse coat color scenario as well as on evolutionary principles in general. Understanding the beach mouse example was a better predictor of good responses to questions about evolution in general than was performance on the course as a whole. This suggests that improvements in evolutionary understanding came mostly from studying the integrated evolution scenarios.

From Science Daily

Huge Earth-Passing Asteroid 'Entirely New Beast'

A big asteroid that flew past Earth last month belongs to a new category of space rock, scientists say.

Asteroid 1998 QE2 and its moon sailed within 3.6 million miles (5.8 million kilometers) of Earth on May 31, making their closest approach to our planet for at least the next two centuries. New radar images captured by the Arecibo Observatory in Puerto Rico are revealing just how unique this binary asteroid is, researchers say.

“Asteroid QE2 is dark, red, and primitive — that is, it hasn’t been heated or melted as much as other asteroids," Arecibo's Ellen Howell said in a statement. "QE2 is nothing like any asteroid we've visited with a spacecraft, or plan to, or that we have meteorites from. It's an entirely new beast in the menagerie of asteroids near Earth."

The 1,000-foot-wide (305 meters) Arecibo dish and NASA's 230-foot (70 m) Deep Space Network antenna in Goldstone, Calif., tracked 1998 QE2 as it approached Earth last month, then kept following the near-Earth asteroid as it receded into the depths of space.

The resulting radar images have helped researchers take 1998 QE2's measure. The dark, cratered main asteroid is 1.9 miles (3 km) wide, and it has a 2,500-foot (750 m) moon that orbits it once every 32 hours.

"QE2's moon is roughly one-quarter the size of the main asteroid," Patrick Taylor, also of Arecibo, said in a statement. "Similarly, our moon is also approximately one-fourth the size of our planet."

Studying the moon and its orbit should help scientists determine the mass of the main asteroid, which in turn will shed light on the object's composition, researchers said.

Asteroid 1998 QE2 was discovered in August 1998 by astronomers working with MIT's Lincoln Near Earth Asteroid Research program in New Mexico. The space rock completes one lap around the sun every 3.8 years.

There was never any danger of 1998 QE2 hitting Earth during last month's flyby, scientists say. If it had hit us, the damage would have been severe; researchers think that any asteroid bigger than 0.6 miles (1 km) is capable of inflicting damage on a global scale, primarily by altering the planet's climate.

Read more at Discovery News

Jun 14, 2013

Prehistoric-Looking Horses Roaming China's Plains Again

In the harsh desert steppe of far northwestern China five prehistoric-looking Przewalski's horses, once classed as extinct in the wild, emerge from the endless plains.

The horses -- named after a Russian officer and explorer who spotted them around 1880 -- bear a striking resemblance to those depicted in European cave paintings, with short necks, spiky manes and a yellow hue.

They graze calmly on a few strands of straw as the wind whips across the vast, open landscape.

"These ones here, they can be approached. The others will run away as soon as you get within 300 yards of them," says Sun Zhicheng, an official at the 1.6-million-acre West Lake national nature reserve.

According to the International Union for Conservation of Nature, Przewalski's horses once roamed as far as Western Europe.

But as the centuries passed, climatic change reduced their habitat and the remainder were so widely hunted, mainly for food, that they were classified as extinct in the wild in 1960 -- although a living specimen was later found in Mongolia.

But a few survived in European zoos, and now efforts are under way to reintroduce them to the wild.

The Chinese project near Xihu in Gansu province faces daunting challenges -- freezing winters, sweltering summers and limited supplies of food and water.

According to Chinese legend, Sun says, the animals were discovered two millennia ago by an exiled criminal around the oasis of Dunhuang, a crossroads on the Silk Road.

"A man had been convicted and banished from Dunhuang. While he was walking near a lake he saw one of these horses.

"He made a mannequin and put it on a path the horse would follow. One day he took the place of the mannequin, and he was able to catch the horse to offer it to the emperor.

"The man then lied to the emperor Han Wudi, saying the horse had sprung out of a spring. And he called it a heavenly horse. The emperor loved the horse so much that he wrote a poem about it."

In 1986 China purchased 18 of the horses from the United States, Britain and Germany and has since bred them in captivity, with their numbers growing to more than 70.

Starting in 2010, carefully selected batches have been released into the reserve.

"Now there are 27, 16 females and 11 males," says Sun. "We even registered the birth of a foal in July 2011, a new success in our reintroduction process."

But very few animals can endure an environment as hard and dry as Gansu's desert steppe.

Przewalski's horses require daily access to water that is within a 30-kilometre (20-mile) range and does not freeze in winter. They also need 22 pounds of dry food per day, relatively close to the water.

In a region that receives less than 1.5 inches of rain per year, many of these conditions could become problems, says Sun.

The reserve is taking back-up measures to improve the horses' chances.

"We have increased the water supply by expanding 10 wells. At a later point we are thinking of bringing water from the river.

"In winter we have to break the ice so that the horses can drink."

The horses eat grasses and certain plant species, says reserve employee Lu Shengrong, but when vegetation becomes sparse in winter-time, they will be fed dry alfalfa, straw, black beans and corn.

Of the 2,000 or so Przewalski's horses that now exist worldwide, about a quarter are part of efforts to reintroduce them to the wild, says Claudia Feh, a biologist doing similar work in Mongolia, where several hundred have been released.

The worst threat they face, she says, are ordinary horses, which can infect them with disease or crossbreed with them, diluting the gene pool.

Read more at Discovery News

Medici Children Suffered From Rickets

The children of the wealthy and powerful Medici family suffered from rickets as result of malnutrition and prolonged indoor life, a new paleopathological study has revealed.

Researchers at the University of Pisa made the discovery after analyzing nine skeletons taken from under the floor of the Medici Chapels in the Basilica of San Lorenzo in Florence.

The children’s bones were found in 2004 after the discovery of a secret entrance in the intact tomb of Giangastone (1671–1737), the last Grand Duke of the clan that dominated the Florentine Renaissance.

“The removal of a marble disc in the floor of the chapel, initially considered only a simple floor decoration, displayed a secret opening with a small stone stair leading to a hidden crypt,” palaeopathologist Valentina Giuffra, Gino Fornaciari and colleagues of Pisa and Siena Universities, wrote in the International Journal of Osteoarchaeology.

In the crypt, a large sarcophagus contained the remains of Giangastone, while on the floor lay eight coffins and several scattered bones — the result of the Arno flooding of 1966. The ninth coffin was found in a nearby tomb.

Analysis of the bones revealed that the children’s ages ranged from newborn to about 5 years old. Six out of nine showed the classic signs of rickets, such as curved arms and bow legs — a consequence of trying to crawl or walk on pathologically soft bones.

One of the children clearly identified, Filippo (1577-1582), the seventh child of Francesco I and Giovanna of Austria, also known as Don Filippino, had a slightly deformed skull. According to the researchers, rickets was the culprit.

A skeletal disorder characterized by a lack of vitamin D, rickets is usually associated with poor children living in heavily polluted cities where exposure to sunlight is limited.

“Diagnosis of a metabolic disease linked to vitamin D deficiency would appear unexpected in children brought up at the court of a Renaissance high social class family like the Medici of Florence,” the researchers observed.

Rather than from defects in the metabolism, the disease originated from the Medicis’ desire to protect their offspring, raising them according to the highest social standards for their times.

“During the Renaissance, a common opinion prescribed that children were not to be weaned before the second year of life; for this reason, among the elite classes, wet nursing was a very widespread practice,” the researchers wrote.

Indeed, the Medici princes were never weaned until they were at least 2; starting from eight to nine months, woman’s milk was integrated with paps made of soft bread and apples. Cereals and breast milk are known to supply little vitamin D, while fruit contains none.

“With prolonged breast-feeding, vitamin D deficiency is highly expected to rise, in particular if the other main risk factor, inadequate sunlight exposition, is associated with a diet based on maternal milk,” the researchers said.

They added that two hours per week is the required minimum period of exposure to sunlight for infants if only the face is exposed — something the Medici children did not enjoy.

At that time, skin color was a way to distinguish the upper class from peasants engaged in field work.

“A pale ivory skin was considered a sign of health and elegance,” the researchers wrote.

Kept indoors in large palaces where the opportunity of sunlight exposure was significantly reduced, the Medici children were also wrapped in many heavy layers. In keeping with the Renaissance customs, infants were heavily swaddled, leaving very little skin exposed.

Even two newborns showed signs of rickets, although they should have received vitamin D from their mothers through the placenta.

Rickets may have been the cause of death for these children or may have contributed to worsening other problems present at birth.

According to the researchers, the mothers also had a vitamin D deficiency. Heavy makeup, to prevent skin exposure to sunlight, and repeated childbearing — Eleanor of Toledo bore 11 children in 14 years — might have been the cause for their low-level vitamin D.

Read more at Discovery News

Fab Abs? Ancient Fossil Fish Had Em!

Palaeontologists have discovered an ancient fossil fish that shows surprising signs of having abdominal muscles, previously thought to have only developed in land animals.

Mapping the oldest fossilized vertebrate muscles ever seen -- in Gogo fish thought to be 380 million years old -- researchers worked out the position of the muscles and the orientation of the muscle fibers.

The fossil fish, found in the Kimberley region of Western Australia, are enclosed in limestone nodules and are known for their exceptional preservation.

"The muscles in the abdomen cavity that we found weren't expected because even in living fish their main mode of propulsion is of course to flap their tails to left and right so all the muscles are sitting on the side of the body," said Gavin Young from Australian National University's Research School of Earth Sciences.

"What's interesting is when we found these muscles and did some comparisons, the only comparable muscles are in... land animals," he added to AFP.

He said the question now was whether these muscles had the same function as abdominals seen in land animals.

In the study published in Science, the researchers prepared and analyzed the muscles in a small number of specimens from three different species.

"(The ancient fish) have already revealed soft tissues such as nerve and muscle cells, the oldest known vertebrate embryos, and even a preserved umbilical cord," Young said.

The latest study went further and mapped the musculature of the ancient fish for the first time, possible after researchers realized that soft tissues had been preserved in some of the specimens, though it was being destroyed in the earlier process of acid etching the skeletons.

Curtin University associate professor Kate Trinajstic, a chief investigator on the ANU-based research into early vertebrate evolution, said the team had been "stunned to find that our ancient fossil fishes had abs!"

"Abdominal muscles were thought to be an invention of animals that first walked onto the land but this discovery shows that these muscles appeared much earlier in our evolutionary history," she said.

Read more at Discovery News

Radioactive Mountain Yields Rare-Earth Digs

Red state or blue state, liberal or libertarian, Americans share an addiction to rare-earth elements imported from China.

Green technologies such as electric cars, wind turbines, solar panels and fluorescent light bulbs rely on rare-earth metals. The military depends on rare earths for guided missile systems, satellites and unmanned drones. NASA's spacecraft carry powerful rare earth magnets to Mars and outer space. The magnets also miniaturized iPads, computers and high-tech headphones.

China controls 95 percent of the world's rare-earth supply. The key to this monopoly isn't an abundance of rare-earth deposits, but its expertise in processing ore into oxides and pure metal. The ore tends to carry uranium and thorium, the most radioactive element on the planet, and extracting the metal is typically a long, multistage process involving toxic chemicals.

"We know where the deposits are. Having them end up in your iPhone is not a straight or simple process," said Brad Van Gosen, a geologist with the U.S. Geological Survey (USGS) in Denver.

A few years ago, China showed its power, and cut the supply of rare earths to a trickle. The move sent the United States and other countries scrambling to end their reliance on China. Prices soared, drawing new investors and mining companies into the rare earth market. Now, the United States has one new mine nearly finished and two more in the permitting stages. But the crucial element in escaping China's rare-earth rule isn't new mines, it's rebuilding the expertise and infrastructure to process the finicky metals, experts say.

Price war

In 2010, China spiked the cost of rare-earth elements when it started restricting exports and charging foreign companies higher prices. The price bubble sparked a worldwide frenzy to escape China's control. A new Australian-owned processing plant just opened in Malaysia. Others are planned in Canada, Europe and Africa. Several companies are also trying to develop an American supply for rare earths, some with support from the Department of Defense.

"The rare earths are very much strategic metals, and particularly very much of strategic importance to the defense industry," said Curt Freeman, president of Avalon Development Corp. in Fairbanks, Alaska, a mining consulting firm. "There's a queasy feeling in Congress and the Department of Defense," he said.

In the United States, California's Mountain Pass mine reopened in 2010 and is expected to start producing light rare-earth elements this year. The mine was once the world's biggest producers of rare earths, but shut down in 2002 because of environmental problems and falling prices. Another mine is proposed in Wyoming, by Canadian company Rare Element Resources, but faces opposition from local residents.

One of the biggest rare-earth gambles is at Alaska's Bokan Mountain. Once mined for uranium, the granite peak on Prince of Wales Island contains rich veins of the harder-to-find heavy rare-earth elements. The project has strong support from Alaska's legislature and from nearby communities. A Canadian company plans to extract the ore and transform it into oxides with a custom-built processing plant. Therein lies the challenge.

Despite their name, rare earths are actually common in Earth's crust, though in low concentrations. The moniker is a holdover from the 19th century, when researchers discovered the oddly named elements in rarely found minerals. The 17 elements share a close affinity, with similar chemical properties and atomic weights. Bokan Mountain is one of the few spots on Earth with a bounty of heavy rare-earth elements, which have higher atomic weights. It's especially elevated in yttrium, which appears in everything from cubic zirconia and car pollution sensors to lasers, rockets and jet engines.

Because rare earths are often all mixed together in one rock, separating the heavy rare earths usually requires removing the lighter ones first. This is typically done with a series of chemical tanks and solvents. Plus, there's the radioactive uranium to dispose of. But mine owner Ucore says it has a new solid-extraction technology that greatly simplifies this process. The technique relies on nanotechnology to remove impurities and concentrate the heavy rare earths into oxides, according to Ucore. The Department of Defense funded Ucore's ore extraction research with a contract in October 2012.

But a USGS-funded study found Bokan Mountain's vein system is very complex, with a mix of at least two dozen ore minerals, the agency's Van Gosen said. The study was published Jan. 22 in the Canadian Journal of Earth Sciences.

"It's getting more and more complicated the more we look at it," Van Gosen said.

Metals industry consultant Gareth Hatch notes that processing is the biggest hurdle for rare-earth mining companies.

"Processing is the key challenge for deposits that particularly are skewed toward the middle and heavy rare earths, because they have some unusual minerals that haven't been processed before," said Hatch, founding principal of Technology Metals Research. Hatch is helping develop a rare earth processing company in Canada.

The USGS has several ongoing projects examining the geology of Bokan Mountain, to better understand how the minerals appeared.

"The idea is to develop a fundamental understanding of how these deposits get started in the first place in Earth's crust, and use it to go look for resources that the U.S. public needs," said Susan Karl, a USGS geologist based in Anchorage.

Ucore board member Jaroslav Dostal, an emeritus professor at Saint Mary's University in Halifax, Nova Scotia, was lead author of the Bokan Mountain study. The grant program that provided funding for the study, the USGS Mineral Resources External Research Program, has awarded projects to private industry and foreign recipients in the past.

Investing in processing

The USGS also has projects exploring the geology of other rare-earth deposits. Since 2010, the House of Representatives has introduced legislation to curb mining regulations and fund rare-earth research and development, which have yet to pass the Senate. Recycling of rare-earth metals, which is not always made possible with high-tech gadgetry, is another way to reduce dependency on China's supply. Earlier this year, the Department of Defense recommended stockpiling $120 million of critical heavy rare-earth elements. But industry experts say money would be better spent on building American expertise and infrastructure in processing rare earths. [The Common Elements of Innovation]

Read more at Discovery News

Jun 13, 2013

Dead Daddy Guppies Keep Making Babies

From beyond the grave, male Trinidadian guppies continue to reproduce. This isn’t a Father’s Day zombie love story though. Evolutionary biologists recently discovered that female Trinidadian guppies store reservoirs of sperm from long-dead guppy daddies for up to 10 months.

Storing sperm could allow these guppy gals to be pioneers, settling new waters and giving birth to genetically diverse offspring. Females swim better than males, so the females can colonize new territory more easily.

“Populations that are too small can go extinct because close relatives end up breeding with each other and offspring suffer from inbreeding,” David Reznick, professor of biology at the University of California, Riverside and leader of the guppy study published in Proceedings of the Royal Society B, said in a press release. “If there are stored sperm, then the real population size is bigger than the number of animals you see. Also, stored sperm can increase genetic variation in other ways.”

Females live for up to two years, compared to the three to four month lifespan of a male. Keeping dead dads’ sperm on tap could allow females to give birth to a blast from the past male color pattern that will have all the other guppy girls going gaga. Female guppies are attracted to males with unusual patterns.

“In addition to learning about sperm storage, this is the first time we are learning about the huge differences in lifespan between males and females,” Reznick said. “If we were to use males to estimate generation time, then these differences mean that lucky females live for three generations. A human equivalent would be for us to have women around who were 90 years old and still very fertile.”

Read more at Discovery News

Are Languages Shaped By Geography?

The way different languages sound may depend on the geography of the landscape on which they're spoken, new research suggests.

A study of more than 550 languages around the world found that tongues spoken in high-altitude regions contain more sounds called ejective consonants, made with a burst of air, than languages closer to sea level.

Ejectives may be more common in these regions because the sounds are easier to produce there, or possibly because they minimize water loss from the mouth in dry, high-altitude environments, said study author Caleb Everett, an anthropological linguist at the University of Miami.

Traditionally, linguists have assumed that geography doesn't play a role in shaping languages, with the exception of vocabulary specific to certain environments or wildlife. A handful of small studies have suggested that languages in warm climates use more vowels than languages in cold climates, but the findings are controversial.

Everett set out to investigate how other aspects of geography, namely altitude, might be linked to certain sounds, or phonemes, in a language. Specifically, he looks at ejectives, a class of sounds (not present in English) produced by puffs of air in the mouth as opposed to the lungs. Everett suspected these sounds might be more common at high altitudes, where the lower air pressure would make them easier to produce.

To test this hypothesis, Everett analyzed phoneme data on 567 languages from the World Atlas of Linguistic Structures Online. He compared the data to the altitudes where the languages were spoken, obtained using geographic mapping software.

Languages containing ejective sounds were found to occur at or near five of the six major inhabited high-altitude regions, including in North and South America, southern Africa and Eurasia, Everett found.

The one exception to this pattern was the Himalayan Plateau — that region was not home to any languages containing ejectives. "It is not particularly surprising that one region should present such an exception," Everett wrote in his paper, "and in fact it strikes us as remarkable that only one region presents an exception."

Languages at high altitudes may have evolved to have ejective sounds because less effort is required to produce these bursts of air in thinner atmospheres, Everett speculates. His basic calculations of the air pressure needed to make these sounds support this explanation.

Read more at Discovery News

The Hunt is on for Habitable Exomoons

Our solar system is full of moons. Of the 8 major planets, 6 of them have at least one natural satellite in tow, and several of those moons are very interesting places. Icy moons in the outer solar system may even be secretly harboring life. But what about moons elsewhere in the galaxy?

The Hunt for Exomoons with Kepler (HEK) is an astronomy project intended to try and find exomoons. And not just any exomoons; the kind of moons that could be a haven for life. While the Kepler telescope has, sadly, been forced into retirement, the data it collected lives on. And there’s a lot of data still to sift though.

The idea of habitable moons is already well known to fans of science fiction. From Star Wars to Prometheus, the idea of a habitable world orbiting a gas giant is quite well ingrained on our collective subconscious. Perhaps this is what inspired the idea back in 2009 that we could look for exomoons with Kepler.

Since then, the idea has come forward in leaps and bounds, and we know of several gas giants within their parent stars’ habitable zones. Some even expect that exomoons may even be the best place to start looking for extrasolar life. The latest development in this story saw a team of astronomers, lead by Harvard-Smithsonian‘s David Kipping, take a closer look at Kepler-22b to try and hone their techniques.

Kepler-22b is a planet with a 95 percent probability of being in its parent star’s habitable zone. Around 620 light-years away from us, it has a radius about 2.4 times as large as Earth, and is about 10 percent as massive as Jupiter. With that size, it’s most likely to be a gas giant.

Unfortunately, no moon was found around Kepler-22b. If it has any moons at all, they must be smaller than half Earth’s mass. Nonetheless, this was far from a wasted exercise. Planet hunters now have a small arsenal of tools and techniques at their disposal — enough for Kipping and his colleagues to draw the conclusion that if any Earth-like moon is there to be found around similar planets, they will find it.

Planet Kepler-22b was chosen for this search for several reasons. As well as being comfortably in the habitable zone and having been confirmed by Kepler observations, this planet also had radial velocity data available for it, and the observations contain very low noise (take it from me, noise in observations is the bane of an astronomer’s life!).

While no Earth-like exomoons could be found around Kepler-22b, the fact that moons should be very easy to see if they’re there is heartening. What’s more, it’s worth bearing in mind that this does not mean that Kepler-22b has no moons at all. For example, Titan, Saturn’s giant moon, has only 2 percent the mass of Earth.

Read more at Discovery News

Andromeda: My God, It's Full of Black Holes

The central region of the Andromeda galaxy is chock-full of black holes, according to extensive observations with NASA’s Chandra X-ray Observatory. 26 new stellar-mass black hole candidates have been identified, adding to nine previously known and bringing the grand total to 35.

It might not sound like a lot compared to the size of an entire galaxy, but it’s many more than have been found so far in our own galaxy’s center and indicates the presence of even more that can’t be seen.

“While we are excited to find so many black holes in Andromeda, we think it’s just the tip of the iceberg,” said Robin Barnard of Harvard-Smithsonian Center for Astrophysics (CfA), lead author of a new paper describing these results. “Most black holes won’t have close companions and will be invisible to us.”

Using data from Chandra and the European Space Agency’s XMM-Newton X-ray Observatory, astronomers were able to spot these otherwise invisible objects by the energy released by superheated material they draw in from nearby stars.

More than 150 Chandra observations, spread over 13 years, were used to identify the 26 new black holes.

The image above combines optical data from the Warner and Swansey Observatory on Kitt Peak in Arizona with an inset of X-ray observations of the central region. The new black hole candidates are circled in yellow.

“By observing in snapshots covering more than a dozen years, we are able to build up a uniquely useful view of M31,” said co-author Michael Garcia, also of CfA. “The resulting very long exposure allows us to test if individual sources are black holes or neutron stars.”

While neutron stars would have exhibited a certain level of X-ray emission and wavelength, these sources were more energetic and brighter, indicating that they are very likely stellar-mass black holes — the collapsed remains of stars five to ten times the mass of our sun.

Because the Andromeda galaxy’s central bulge is bigger than the Milky Way’s,  more black holes can form there — a scenario that was expected by astronomers and now supported by these Chandra results.

Read more at Discovery News

Jun 12, 2013

New Olive-Eyed Butterfly Can't Fool Around

How good of an eye do you have for new species? Besides the obvious eye color difference, what else can you spot that distinguishes the new species (left) Ministrymon janevicroy from the old species Ministrymon azia? If you noticed the pebbly texture and grayer color of the new species, you’d be correct. There are other differences that are a bit harder to see, but enough to officially publish the discovery of the new species in ZooKeys at the end of May.

The common English name for the new species will be Vicroy’s Ministreak, which distinguishes it from the Gray Ministreak butterfly — never mind that the Vicroy Ministreak is grayer than the Gray Ministreak (these things happen).

You will not see the new butterfly in any U.S. state except Texas, as its range is from Texas to Guanacaste Province, Costa Rica and in South America on the islands of Curaçao and Margarita. The Gray Ministreak, on the other hand, might cross your path in other parts of the southern U.S., as well as in Brazil, Paraguay, Argentina, and virtually all lowland areas, whether they be a desert in coastal Peru or a rainforest on the Amazon.

The new Vicroy Miniostreak is a bit more selective. It prefers dry deciduous forests and scrublands. Which suits the Gray Ministreak as well. In fact both species have been found in the same locations.

So how can they be different species if they live side-by-side? The answer is called reproductive isolation. This is similar to when two populations of a single species becomes physically isolated from each other and evolve apart, only sexual isolation means there’s something about they way they reproduce that keeps them from mating, and so they can evolve into new species. This is backed up by the genitalia of the Vicroy Ministreak species, which is significantly different from the Gray Ministreak according to the authors of the paper, Robert K. Robbins of the Smithsonian Institution and Jeffrey Glassberg of the North American Butterfly Association.

Read more at Discovery News

Giant, Flying Reptiles Once Filled England's Skies

Flying reptiles were prevalent over the skies of Cretaceous England 110 million years ago, a new study suggests.

The winged reptiles, pterosaurs, were the largest flying animals to have ever lived. The largest had a wingspan of over 30 feet and weighed about 550 pounds.

The study, published in the journal ZooKeys, reports that a bunch of pterosaur fossils were unearthed at a site known as Cambridge Greensand, located in the eastern part of England. (The idea of a flying reptile conjures up mythical images from Harry Potter films, many of which included locations at and around Oxford University, but not so much at Cambridge.)

The flying reptiles displayed a remarkable diversity in their appearances, according to Taissa Rodrigues and colleagues.

Rodrigues, a paleontologist from the Federal University of Espiritu Santo, and team determined that some species had head crests of different sizes and shapes, while others had none. Most of the flying animals had large teeth at the tip of their snouts and were fish eaters, but others had smaller teeth, suggesting different feeding preferences.

The paleontologists were able to identify 14 different species, belonging to at least five different genera, showing a much greater diversity than previously thought.

Another find was that these U.K. flying reptiles turned out to be closely related to species unearthed in northeastern Brazil and eastern China.

“This is very interesting, especially because the continents had already drifted apart,” Rodrigues said in a press release. “If these animals were migratory, we would expect to find the same species in all these deposits.”

Instead, it looks like England, Brazil and China all had their own species and genera of pterosaurs.

Pterosaur power didn’t last too long, though. The English ones went extinct a few million years later.

Today’s birds might cheer the fact that pterosaurs are no longer with us, since the latter were early predators and competitors of birds.

Read more at Discovery News

7 Craziest Intelligence Leaks in U.S. History

The Pentagon Papers

The news that the U.S. government has been recording data from phone calls and Internet activity, broken by former CIA employee Edward Snowden, is just the latest in a long line of legendary leaks. Here are some of the most notorious leaks in U.S. history.

In June 1971, The New York Times published sections of a top-secret Department of Defense report on the country's involvement in Vietnam from 1945-1967. Dubbed the "Pentagon Papers," the report detailed how the Johnson administration and others repeatedly misled Congress and the public about the causes and progress of the Vietnam War, according to the History Channel.

The report was leaked by antiwar activist Daniel Ellsberg, a former Defense Department analyst working for the RAND Corp., who stole it from the Pentagon and sent copies to the Times. The Pentagon Papers' publication fueled the antiwar movement and sparked a debate over the freedom of the press to divulge "classified" information and the public's right to know about government affairs. President Richard Nixon tried but failed to get the Supreme Court to prevent further publication of the papers.

The Watergate Scandal

One of the best-known leaks, of course, is the Watergate scandal of Richard Nixon's presidency. On June 17, 1972, five men were arrested for breaking into the headquarters of the Democratic National Committee at the Watergate hotel complex in Washington, D.C., and installing illegal wiretaps. The men were linked to a fundraising group for Nixon's 1972 re-election campaign, but the Nixon administration denied any involvement.

Later in 1972, Washington Post reporters Carl Bernstein and Bob Woodward exposed the administration's role in the scandal and cover-up. Their key source was an informant nicknamed "Deep Throat," who was later revealed to be former FBI agent W. Mark Felt. A series of Senate hearings nailed the lid on Nixon's coffin, and he resigned from the presidency in 1974 -- the first president to do so.

The Iraq War Logs (WikiLeaks)

The so-called "Iraq War Logs" were just one of many leaks made by the non-profit organization WikiLeaks, founded by Australian journalist and activist Julian Paul Assange. The organization publishes secret or classified information or news from anonymous sources. In October 2010, WikiLeaks published Army field reports from 2004 to 2009 that listed the number of civilian deaths as 66,081 out of 109,000 total recorded deaths. The leaked logs confirmed some partially reported events. For instance, some American troops had been classifying civilian deaths as enemy deaths. The Iraq War Logs represent the largest leak in U.S. history.

The Plame Affair

In 2003, a case of leaked identity ended the career of a CIA agent. On July 6, 2003, The New York Times published an Op-Ed by former U.S. diplomat Joseph Wilson, which questioned the reasons given by President George W. Bush's administration for invading Iraq earlier in 2003.

Wilson, who had been a CIA envoy to Niger in 2002, said Bush's claim that Iraq had attempted to buy enriched uranium yellowcake -- a step toward enriched uranium but not weapons-grade yet -- from Niger was unsubstantiated. In response, Washington Post columnist Robert Novak wrote a column on July 14, 2003 criticizing Wilson and referring to Wilson's wife, Valerie Plame, as an "agency operative" -- blowing her cover.

Wilson accused the White House of leaking Plame's identity as retribution for his Op-Ed, prompting an investigation. Prosecutor Patrick Fitzgerald interviewed Bush, Vice President Dick Cheney and other administration officials and journalists. New York Times reporter Judith Miller, who conducted interviews in the leak but had never written an article about it, refused to testify and was held in contemp. She served time at a federal detention center, but was released after three months when Lewis "Scooter" Libby, Cheney's chief of staff, signed a waiver granting Miller permission to speak.

In 2007, Libby was convicted of obstruction of justice, perjury and making false statements to government investigators. Libby was sentenced to prison, but Bush later reduced his sentence.

Read more at Discovery News

Genetics of Barrel-Spoiling Bad Apples

Long before there were “life hacks,” there was folk wisdom. One classic kitchen tip was to put a ripe apple in a paper bag with a green banana to speed the banana’s ripening. Chemically, ethylene gas released by the ripe apple caused the banana to become yellow and delicious. A similar chemical reaction causes “one bad apple to spoil the whole bunch,” because a single piece of ripe fruit speeds up the ripening and subsequent rotting of its neighbors.

However, until now, the exact genetic mechanism behind this kitchen chemistry had been a mystery.

Recent research discovered that etylene gas acts as a hormone to activate a particular gene in plants’ DNA, known as Ethylene Insensitive3 (EIN3). Ethylene’s effect on that gene then ripples out and causes a multitude of other chemical reactions in fruits and many other plants. The study was published online in eLife.

“I have been trying, for several decades, to understand how a simple gas—two carbons and four hydrogens—can cause such profound changes in a plant,” said study co-author Joseph R. Ecker of the Salk Institute for Biological Studies in a press release. “Now we can see that by altering the expression of one protein, ethylene produces cascading waves of gene activation that profoundly alters the biology of the plant.”

“Now that we know the genes that ethylene ultimately activates, we will be able to identify the key genes and proteins involved in each of these branch pathways, and this might help us manipulate the discrete functions this hormone regulates,” said Ecker.

Manipulating ethylenes effects on EIN3 could allow:

  • Breeding or engineering plants that slow down growth at specific time
  • Accelerating or slowing fruit ripening
  • Slowing rotting
  • Breeding crops resistant to certain diseases

The newly discovered ethylene effects on EIN3 influence all other plant hormone signaling.

“If ethylene tells a plant to stop growing, it has to control other hormones that are telling the plant to grow,” said Ecker. “Imagine you are in a recording studio and you have one of those tables in front of you that have all of those switches. If you start pushing up the dials for one sound effect, you probably turn down the dial for other sound.”

From Discovery News

Jun 11, 2013

Understanding the Heart's Rhythm

The heart's regular rhythm is crucial to the delivery of oxygenated blood and nutrients to all the organs of the body. It is regulated by a bundle of cells called "the pacemaker," which use electrical signals to set the pace of the heart. Dysfunction in this mechanism can lead to an irregular heartbeat, known as arrhythmia, and often necessitates the implantation of an artificial pacemaker.

Previously, scientists found that many cases of inherited arrhythmias originating in the pacemaker could be attributed to functional defects in the channels responsible for the flow of sodium and calcium. Now Prof. Bernard Attali of Tel Aviv University's Sackler Faculty of Medicine and his fellow researchers have discovered a previously unidentified potassium channel in the cardiac pacemaker which helps to regulate the heartbeat. He hypothesizes that some cases of unexplained arrhythmia could be traced back to irregularities in this channel.

Developing therapies to target this potassium channel could be a significant step towards circumventing artificial pacemakers in favor of biological options, says Prof. Attali. This research has been reported in the journal PNAS.

A cellular heart model

To further investigate the workings of the biological pacemaker, Prof. Attali and his fellow researchers turned to embryonic stem cells isolated from human subjects. Once coaxed into differentiating into cardiac tissue, these cells began to beat automatically, like a small human heart.

While observing and recording the cells' electrical activity, researchers discovered the existence of a new channel in the pacemaker. Facilitating the flow of potassium from the pacemaker cells, this channel triggers the repolarization of the cells -- returning the cell membrane from a "beating" to a "resting" state -- and automatically renews or "restarts" the cycling of the heart.

Since discovering this channel in the embryonic heart, the researchers have shown that the channel exists in the adult heart as well. This finding deepens medicine's understanding of the heart's pacemaker function, which has been the subject of scientific research for over a century.

Screening for mutations
The next step is to conduct screening for mutations in the gene encoding the potassium channel, a process already underway at the TAU-affiliated Sheba Medical Center. "We would like to understand if there are genetic diseases linked to this channel," such as a previously unknown cause of arrhythmia, explains Prof. Attali. If a mutation is found, researchers can begin the hunt for drug compounds, which target this channel. The ultimate goal, he adds, is to be able to treat heart arrhythmias biologically by altering the properties of the pacemaker bundle, rather than relying on a human-made electric pacemaker.

Read more at Science Daily

Dog Disease Threatens Sumatran Tigers

Deadly canine distemper virus doesn’t limit itself to dogs and their kin anymore. By 2000, the disease had been reported in all families of land carnivores from racoons to hyenas to lions. Now, the disease threatens the Sumatran tiger (Panthera sumatrae), a critically endangered species.

The International Union for the Conservation of Nature estimates the viable breeding population of the Sumatran tiger numbers only 176 to 271 individuals out of a total population of 400 to 500 on the Indonesian island of Sumatra. Troubling signs of an outbreak of canine distemper virus (CDV) may threaten those surviving Sumatran tigers, reported the BBC.

Brain damage from CDV can cause the cats to lose their natural fear of humans. The cats will then wander into villages or fail to flee from illegal hunters. In either case, the tiger usually ends up shot. A few cases of this behavior have been noted in Sumatra, but veterinarians haven’t been able to test for CDV in these wandering tigers.

“The big threats facing tigers are habitat loss and degradation and poaching, but I think the third big threat now is likely to be disease, particularly one like CDV,” John Lewis, director of Wildlife Vets International, told the BBC.

In September, Lewis will work with a team of Indonesian veterinarians to develop a system to monitor for CDV and find a laboratory where samples can be analyzed.

“Once we have got that nailed down then we start work and try to design some sort of mitigation strategy, and that won’t be easy,” said Lewis.

Canine distemper virus kills most animals it infects. A paper in the Journal of Zoo and Wildlife Medicine noted that disease is second only to rabies in mortality rate and has been identified in all families of land carnivores: Canidae, Felidae, Hyaenidae, Mustelidae, Procyonidae, Ursidae, and Viverridae.

A study in the Journal of Veterinary Diagnostic Investigation documented CDV infections that killed 17 lions, tigers and leopards in zoos. Vets believed the cats had contracted the disease after eating infected racoons. A similar study in Clinical and Vaccine Immunology determined that CDV had killed at least 19 lions and tigers in Switzerland over the past few decades.

From Discovery News

New Layer of Human Eye Found

Ophthalmology textbooks describe five layers of the human cornea. They’ll have to be rewritten, says University of Nottingham Professor Harminder Dua, who recently discovered a sixth layer.

“Having identified this new and distinct layer deep in the tissue of the cornea, we can now exploit its presence to make operations much safer and simpler for patients,” she said in a press release.

“From a clinical perspective, there are many diseases that affect the back of the cornea which clinicians across the world are already beginning to relate to the presence, absence or tear in this layer.”

The new layer, called the Dua’s Layer in honor of the professor, is described in the journal Ophthalmology. It’s too thin to be seen; at 15 microns, it’s smaller than beach sand and mist, and makes up a small fraction of the cornea, which is 550 microns thick. It’s located toward the back of the cornea. The scientists detected it through electron microscopy after injecting tiny bubbles of air into donated corneas to separate the layers.

Already, scientists say they have a better understanding of certain diseases of the cornea. Corneal hydrops, for example, occurs when fluid builds up in patients with a deformity of the cornea and produces a bulge. Now researchers think the bulging is caused by a tear in the Dua’s layer.

It could also help in eye surgeries: A surgeon could inject a bubble next to the Dua’s layer to test how strong it is, for example.

From Discovery News

Black Hole Snoozes, Not Bothered With Eating Stuff

News about black holes is usually accompanied by some fun description of them eating stuff. Stars, planets, even asteroids are on the galactic menu. But in the case of the supermassive black hole at center of NGC 253 (the Sculptor galaxy), the opposite is true. It’s not doing much at all. In fact, it appears to have taken leave from its supermassive duties of reigning gravitational terror over the matter inside its galactic core.

“Our results imply that the black hole went dormant in the past 10 years,” said Bret Lehmer of the Johns Hopkins University, Baltimore, and NASA’s Goddard Space Flight Center, Greenbelt, Md. “Periodic observations with both Chandra and NuSTAR should tell us unambiguously if the black hole wakes up again. If this happens in the next few years, we hope to be watching.” Lehmer is lead author of the new study published in the Astrophysical Journal.

Although the black hole is taking a nap, that doesn’t mean the galaxy isn’t picking up the slack. NGC 253 is one of the nearest “starburst” galaxies to the Milky Way, some 13 million light-years away, churning out newborn stars at an accelerated rate. It may seem surprising, then, that the black hole, with a mass of 5 million suns, is able to sleep through the star-forming commotion.

“Black holes feed off surrounding accretion disks of material. When they run out of this fuel, they go dormant,” said co-author Ann Hornschemeier of Goddard. “NGC 253 is somewhat unusual because the giant black hole is asleep in the midst of tremendous star-forming activity all around it.”

This apparent contradiction provides an opportunity for astronomers trying to understand the nature of starburst galaxies and the part their central black holes have to play in galactic evolution.

It is thought that the supermassive black holes that live in the hearts of the majority of galaxies grow at the same rate as their host galaxies. However, black holes are also known to extinguish star formation should they start feeding, generating a hellish environment near the galactic hub — intense radiation generated by an active black hole can cause incredible disruption.

In the case of NGC 253, astronomers cannot be sure whether the rate of star formation is increasing or decreasing, but they are keeping a close eye on the black hole.

In 2003, NGC 253′s black hole was an entirely different creature. It was highly active, generating X-ray radiation spotted by NASA’s Chandra X-ray Observatory, indicating it was consuming matter. But in followup studies in 2012 using Chandra and NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR), the black hole had fallen silent, indicating it had stopped accreting material.

Read more at Discovery News

Jun 10, 2013

Unfrozen Mystery: H2O Reveals a New Secret

Using revolutionary new techniques, a team led by Carnegie's Malcolm Guthrie has made a striking discovery about how ice behaves under pressure, changing ideas that date back almost 50 years. Their findings could alter our understanding of how the water molecule responds to conditions found deep within planets and could have implications for energy science.

Their work is published in the Proceedings of the National Academy of Sciences.

When water freezes into ice, its molecules are bound together in a crystalline lattice held together by hydrogen bonds. Hydrogen bonds are highly versatile and, as a result, crystalline ice reveals a striking diversity of at least 16 different structures.

In all of these forms of ice, the simple H2O molecule is the universal building block. However, in 1964 it was predicted that, under sufficient pressure, the hydrogen bonds could strengthen to the point where they might actually break the water molecule apart. The possibility of directly observing a disassociated water molecule in ice has proven a fascinating lure for scientists and has driven extensive research for the last 50 years. In the mid-1990s several teams, including a Carnegie group, observed the transition using spectroscopic techniques. However, these techniques are indirect and could only reveal part of the picture.

A preferred method is to "see" the hydrogen atoms-or protons-directly. This can be done by bouncing neutrons off the ice and then carefully measuring how they are scattered. However, applying this technique at high enough pressures to see the water molecule dissociate had simply not been possible in the past. Guthrie explained that: "you can only reach these extreme pressures if your samples of ice are really small. But, unfortunately, this makes the hydrogen atoms very hard to see."

The Spallation Neutron Source was opened at Oak Ridge National Laboratory in Tennessee in 2006, providing a new and intensely bright supply of neutrons. By designing a new class of tools that were optimized to exploit this unrivalled flux of neutrons, Guthrie and his team-Carnegie's Russell Hemley, Reinhard Boehler, and Kuo Li, as well as Chris Tulk, Jamie Molaison, and António dos Santos of Oak Ridge National Laboratory-have obtained the first glimpse of the hydrogen atoms themselves in ice at unprecedented pressures of over 500,000 times atmospheric pressure.

"The neutrons tell us a story that the other techniques could not," said Hemley, director of Carnegie's Geophysical Laboratory. "The results indicate that dissociation of water molecules follows two different mechanisms. Some of the molecules begin to dissociate at much lower pressures and via a different path than was predicted in the classic 1964 paper."

"Our data paint an altogether new picture of ice," Guthrie commented. "Not only do the results have broad consequences for understanding bonding in H2O, the observations may also support a previously proposed theory that the protons in ice in planetary interiors can be mobile even while the ice remains solid."

Read more at Science Daily

The Iceman Suffered Brain Damage Before Death

An injury to the head, not an arrow wound, may have killed Ötzi the Iceman, the 5,300-year-old mummy found in the Italian Alps, says a new paleoproteomic study into the brain of Europe’s oldest natural human mummy.

The protein investigation appears to support a 2007 research into the mummy’s brain. The study pointed to a cerebral trauma as the cause of death.

At that time, the research relied on a CAT scan of the mummy’s brain which showed two dark coloured areas at the back of the cerebrum. The inury added to the already known arrowhead wound on the shoulder and wounds on the hand.

Found in Ötzi’s left shoulder in 2001, the stone arrowhead has long been thought to have caused the prehistoric man’s death, fatally severing his left subclavian artery.

The 2007 study suggested that blood loss from the arrow wound would have first made Ötzi lose consciousness, with death coming later, from a violent blow to the head.

Either the man’s killer gave Ötzi the final whack, possibly by hitting him with a stone, or he could have fallen over backwards and hit his head on a rock, the researchers concluded.

The hypothesis had been left unexplored until 2010, when a research team from the European Academy of Bolzano/Bozen (EURAC), Saarland University, Kiel University and other partners decided to investigate the proteome of two pinhead-sized samples of brain tissue from the world-famous glacier corpse.

“The use of new protein-analysis methods has enabled us to pioneer this type of protein investigation on the soft tissue of a mummified human, extracting from the tiniest sample a vast quantity of data which in the future may well answer many further questions,” the researchers said.

Indeed, the scientists were able to identify a total of 502 different proteins.

“Of these, 41 proteins are known to be highly abundant in brain tissue and 9 are even specifically expressed in the brain,” microbiologists Frank Maixner of EURAC, Andreas Tholey of Kiel University, and colleagues wrote in the journal Cellular and Molecular Life Sciences.

“Furthermore, we found 10 proteins related to blood and coagulation. An enrichment analysis revealed a significant accumulation of proteins related to stress response and wound healing,” they wrote.

Found in a corpse almost devoid of blood, the astonishingly well-preserved clotted blood cells provide further evidence that Ötzi’s brain had possibly suffered bruising shortly before his death.

Whether this was due to a blow to the forehead or a fall after being injured by the arrow remains unclear.

“Our data reopens former discussions about a possible injury of the Iceman’s head near the site where the tissue samples have been extracted,” the researchers said.

Read more at Discovery News

Rare 'Sea Serpent' Caught on Video

The giant oarfish is the longest bony fish in the world – reaching, according to some reports, as much as 56 feet from tip to tail, although recorded lengths are somewhat more modest. Its size and its snake-like shape have led to suggestions that it may have been the source of at least some legends of sea serpents.

In Europe, it has been called the “king of herrings,” perhaps because it would sometimes be sighted near herring shoals, which some fishermen believed it guided. In Japan, the coincident appearances of oarfish that have been washed ashore before earthquakes and tsunamis have led to the fish being regarded as a bad omen.

Almost all human encounters with oarfish have been ones in which the fish are dead or drying – washed onto the beach or swimming in a disoriented manner near to shore. The reason for that, simply, is that giant oarfish tend to inhabit deeper waters where human beings rarely venture.

But scientists with the appropriately-named SERPENT project (Scientific and Environmental ROV Partnership using Existing iNdustrial Technology) – a collaboration between marine researchers and the oil-and-gas industry, in which the latter provides the former with resources such as remote operated vehicles (ROVs) – have now recorded not one, not two, but five videos of the giant oarfish in its natural environment.

DNews posted part of one of the videos, complete with narration by lead researcher Mark Benfield, back in 2010; now Benfield and colleagues have compiled all the videos they took between January 2008 and August 2011 – using an ROV at depths of up to 1,600 feet in the Gulf of Mexico – and described their observations in a paper in the Journal of Fish Biology.

Interestingly, despite its long, lean form, the oarfish does not swim like a snake or an eel, but hangs almost vertically in the water. Renfield and colleagues report that the fact the fish did not immediately flee from the ROV’s bright lights suggest that they have few natural predators.

Read more and see the video at Discovery News

The Metallic Snow-Capped Mountains of Venus

Some of Earth’s most majestic features are its towering snowcapped mountains, reaching high enough that they can sculpt our world’s weather systems. But the mountains on Earth are by no means unique, and neither is the snow. Mountains on Venus are also capped with snow. Except that Venusian snow is mostly made from heavy metals.

As you might expect from a planet with such an alien atmosphere, the snow which caps the Venusian mountains is seemingly no less exotic. With the high temperatures on the planet’s surface, water ice is impossible (not that there is much water on Venus). It’s made from lead sulfide and bismuth sulfide, more commonly known as the minerals galena and bismuthinite.

We got our first glimpses under the corrosive clouds of Venus down into its dense, scorching interior late last century. Swathed in thick layers of cloud, roughly 50 kilometers (30 miles) deep, we have only two ways to see the surface of Venus — either descend to the harsh surface as the Soviet Venera landers did, or use radar to see through the clouds from orbit.

When orbiting space probes such as Pioneer Venus and Magellan used their radar instruments to look under the clouds though, they were met with something unusual. The highlands of Venus seemed unusually reflective, appearing much brighter than the lava plains of the Venusian lowlands.

This was quite a puzzle at first, which planetary scientists took some time to disentangle. There were a few possible explanations to choose from. A different surface texture on the mountaintops, perhaps looser soil, might cause them to appear differently, or a different kind of weathering at high altitude might cause the terrain to be different. Alternatively the surface at high altitude may be chemically different.

After Magellan arrived in the orbit of Earth’s twisted sister in the 1990s, it took some more detailed measurements. Everything pointed towards some form of chemical deposition occurring on the higher ground.

As we now understand it, the snow on Venus’ surface is probably more similar to frost. On the lower Venusian plains, temperatures reach a searing 480°C (894°F). This is hot enough that reflective pyrite minerals on the planet’s surface are vaporized, entering the atmosphere as a kind of metallic mist, leaving only the dark volcanic rocks like basalt in the Venusian lowlands.

At higher altitudes, this mist condenses, forming shiny, metallic frost on the tops of the mountains. And Earth’s simmering sibling has plenty of high altitude terrain. Maxwell Montes, the tallest peak on Venus, stands at an altitude of 11 kilometers (6.8 miles) — 3 kilometers (1.8 miles) higher than Mount Everest.

Whether snow genuinely falls on Venus is still unknown, but it’s certainly possible. Sulfuric acid rains have been observed plentifully on Venus as virga — rain which evaporates before it hits the ground, just like over the rainforests on Earth.

The heavy metal snows can be observed anywhere on the surface of Venus over about 2.6 kilometers (1.6 miles). It may not be any coincidence that below this altitude Venus’s atmosphere is technically no longer a gas.

Over 96 percent of the Venusian atmosphere is carbon dioxide, and our sister planet has nearly 100 times as much atmospheric gas as Earth does. This is what causes the huge crushing pressure at Venus’s surface, but that pressure also has a rather strange effect on the gas.

At the pressures and temperatures found near the surface of Venus, carbon dioxide becomes a “supercritical fluid” — an unusual state of matter, partway between a liquid and a gas. Often used on Earth as an industrial solvent, this supercritical carbon dioxide is expected to be found on Venus, coincidentally, at altitudes below around 2 – 3 kilometers (1.2 – 1.8 miles).

Read more at Discovery News

Jun 9, 2013

Opportunity Finds More Hints of Mars Habitability

Scientists using NASA’s long-lived Mars rover Opportunity have found strong evidence that water suitable for the assembly of life’s building blocks flowed through an ancient rock, leaving telltale clay minerals behind.

The detection of aluminum-rich clays in a rock called “Esperance,” raises expectations for what may be Opportunity’s grand finale. The golf cart-sized rover, which is closing in on its 10th anniversary on Mars, is heading toward a 180-foot tall stack of rock that may answer questions about when the planet transitioned from a warm, wet world to the acidic dry desert that appears today.

Opportunity spent three years driving across Mars to reach a large impact basin known as Endeavour Crater. Mineral maps complied from Mars orbiters showed it contained slight amounts of clay minerals.

Clays form when water interacts with rock. Different types of water -- acidic or neutral pH, saltiness, etc. -- and different types of rock form different clays.

Opportunity does not have the onboard chemistry lab that NASA’s follow-on rover Curiosity is using to explore a different region of Mars for life-friendly habitats. But it can scratch into rocks and derive basic mineralogy.

Opportunity and a now-defunct rover twin, Spirit, were launched in 2003 to look for signs of past water on Mars. What they primarily discovered were chemical fingerprints of highly acidic water, more like sulfuric acid.

Esperance tells a different story.

“What we have here is a very different chemistry,” planetary scientist Steve Squyres, with Cornell University, told reporters on a conference call Friday.

“This is water you can drink. This is water that was probably much more favorably in its chemistry, in its level of acidity, for things like pre-biotic chemistry, the kind of chemistry that could lead to the origin of life,” Squyres said.

“This is the most powerful evidence for neutral chemistry water that has been found by Opportunity,” he added.

Curiosity, which landed on Mars in August, also found evidence of pH-neutral water changing the chemistry of a piece of bedrock in its Gale Crater landing site. Analysis of powder drilled out from the inside of the rock also showed all the elements needed to support microbial life.

Results of a second rock sample are pending.

Curiosity is on the move as well, making its way toward Mount Sharp, a 3-mile-high mound of rock rising from the crater’s floor that also shows signs of clay minerals.

Read more at Discovery News

By Trying It All, Predatory Sea Slug Learns What Not to Eat

Researchers have found that a type of predatory sea slug that usually isn't picky when it comes to what it eats has more complex cognitive abilities than previously thought, allowing it to learn the warning cues of dangerous prey and thereby avoid them in the future.

The research appears in the Journal of Experimental Biology.

Pleurobranchaea californica is a deep-water species of sea slug found off the west coast of the United States. It has a relatively simple neural circuitry and set of behaviors. It is a generalist feeder, meaning, as University of Illinois professor of molecular and integrative physiology and leader of the study Rhanor Gillette put it, that members of this species "seem to try anything once."

Another sea slug species, Flabellina iodinea, commonly known as the Spanish shawl because of the orange outgrowths called cerata that cover its purple back, also lives off the west coast. Unlike Pleurobranchaea, however, the Spanish shawl eats only one type of food, an animal called Eudendrium ramosum. According to Gillette, the Spanish shawl digests the Eudendrium's entire body except for its embryonic, developing stinging cells. The Spanish shawl instead transports these stinging cells to its own cerata where they mature, thereby co-opting its victim's body parts for its own defense.

The story of Gillette's Pleurobranchaea-Flabellina research began with a happy accident that involved showing a lab visitor Pleurobranchaea's penchant for predation.

"I had a Pleurobranchaea in a small aquarium that we were about to do a physiological experiment with, and my supplier from Monterey had just sent me these beautiful Spanish shawls," Gillette said. "So I said to the visitor, 'Would you like to see Pleurobranchaea eat another animal?'"

Gillette placed the Spanish shawl into the aquarium. The Pleurobranchaea approached, smelled, and bit the purple and orange newcomer. However, the Flabellina's cerata stung the Pleurobranchaea, the Spanish shawl was rejected and left to do its typical "flamenco dance of escape," and Pleurobranchaea also managed to escape with an avoidance turn.

Some minutes later, his curiosity piqued, Gillette placed the Spanish shawl back into the aquarium with the Pleurobranchaea. Rather than try to eat the Spanish shawl a second time, the Pleurobranchaea immediately started its avoidance turn. 

"I had never seen that before! We began testing them and found that they were learning the odor of the Spanish shawl very specifically and selectively," Gillette said.

Gillette and his team later replicated that day's events by placing a Pleurobranchaea in a training arena 12-15 centimeters from a Spanish shawl, then recorded the Pleurobranchaea's behavior. They returned the Pleurobranchaea to the arena for four more trials in 20-minute intervals, then repeated the procedure 24 and 72 hours later.

In the experiments, those Pleurobranchaea whose feeding thresholds were too high (meaning they were already full) or too low (they were extremely hungry) would either not participate or completely consume the Spanish shawl, respectively. Those that were hungry, but not ravenously so, continued to exhibit the avoidance-turn behavior when placed with the Spanish shawl even 72 hours later.

This showed that Pleurobranchaea was selective in its food choices, but only on a case-by-case basis; the sea slugs already trained to avoid the Spanish shawl would readily eat a species closely related to Flabellina called Hermissenda crassicornis.

Such behaviors come in handy in Pleurobranchaea's natural environment, Gillette said.

"If you're a generalist like Pleurobranchaea, it's highly strategic and advantageous to learn what's good and what's not good so you can decide whether or not to take the risk or of attacking certain types of prey," he said.

Read more at Science Daily