Some genes 'foreign' in origin and not from our ancestors

Many animals, including humans, acquired essential 'foreign' genes from microorganisms co-habiting their environment in ancient times, according to research published in the open access journal Genome Biology. The study challenges conventional views that animal evolution relies solely on genes passed down through ancestral lines, suggesting that, at least in some lineages, the process is still ongoing.

The transfer of genes between organisms living in the same environment is known as horizontal gene transfer (HGT). It is well known in single-celled organisms and thought to be an important process that explains how quickly bacteria evolve, for example, resistance to antibiotics.

HGT is thought to play an important role in the evolution of some animals, including nematode worms which have acquired genes from microorganisms and plants, and some beetles that gained bacterial genes to produce enzymes for digesting coffee berries. However, the idea that HGT occurs in more complex animals, such as humans, rather than them solely gaining genes directly from ancestors, has been widely debated and contested.

Lead author Alastair Crisp from the University of Cambridge, UK, said: "This is the first study to show how widely horizontal gene transfer (HGT) occurs in animals, including humans, giving rise to tens or hundreds of active 'foreign' genes. Surprisingly, far from being a rare occurrence, it appears that HGT has contributed to the evolution of many, perhaps all, animals and that the process is ongoing, meaning that we may need to re-evaluate how we think about evolution."

The researchers studied the genomes of 12 species of Drosophila or fruit fly, four species of nematode worm, and 10 species of primate, including humans. They calculated how well each of their genes aligns to similar genes in other species to estimate how likely they were to be foreign in origin. By comparing with other groups of species, they were able to estimate how long ago the genes were likely to have been acquired.

A number of genes, including the ABO blood group gene, were confirmed as having been acquired by vertebrates through HGT. The majority of the other genes were related to enzymes involved in metabolism.

In humans, they confirmed 17 previously-reported genes acquired from HGT, and identified 128 additional foreign genes in the human genome that have not previously been reported.

Some of those genes were involved in lipid metabolism, including the breakdown of fatty acids and the formation of glycolipids. Others were involved in immune responses, including the inflammatory response, immune cell signalling, and antimicrobial responses, while further gene categories include amino-acid metabolism, protein modification and antioxidant activities.

The team were able to identify the likely class of organisms the transferred genes came from. Bacteria and protists, another class of microorganisms, were the most common donors in all species studied. They also identified HGT from viruses, which was responsible for up to 50 more foreign genes in primates.

Some genes were identified as having originated from fungi. This explains why some previous studies, which only focused on bacteria as the source of HGT, originally rejected the idea that these genes were 'foreign' in origin.

The majority of HGT in primates was found to be ancient, occurring sometime between the common ancestor of Chordata and the common ancestor of the primates.

Read more at Science Daily

Giant sea creature hints at early arthropod evolution

Newly discovered fossils of a giant, extinct sea creature show it had modified legs, gills on its back, and a filter system for feeding -- providing key evidence about the early evolution of arthropods.

The new animal, named Aegirocassis benmoulae in honor of its discoverer, Mohamed Ben Moula, attained a size of at least seven feet, ranking it among the biggest arthropods that ever lived. It was found in southeastern Morocco and dates back some 480 million years.

"Aegirocassis is a truly remarkable looking creature," said Yale University paleontologist Derek Briggs, co-author of a Nature paper describing the animal. "We were excited to discover that it shows features that have not been observed in older Cambrian anomalocaridids -- not one but two sets of swimming flaps along the trunk, representing a stage in the evolution of the two-branched limb, characteristic of modern arthropods such as shrimps."

Briggs is the G. Evelyn Hutchinson Professor of Geology and Geophysics at Yale and curator of invertebrate paleontology at the Yale Peabody Museum of Natural History. First author Peter Van Roy, an associate research scientist at Yale, led the research; Allison Daley of the University of Oxford is co-author.

Since their first appearance in the fossil record 530 million years ago, arthropods have been the most species-rich and morphologically diverse animal group on Earth. They include such familiar creatures as horseshoe crabs, scorpions, spiders, lobsters, butterflies, ants, and beetles. Their success is due in large part to the way their bodies are constructed: They have a hard exoskeleton that is molted during growth, and their bodies and legs are made up of multiple segments. Each segment can be modified separately for different purposes, allowing arthropods to adapt to every environment and mode of life.

Modern arthropod legs, in their most basic form, have two branches. Each is highly modified to cater to a specific function on that leg, such as locomotion, sensing its surroundings, respiration, or copulation; or it has been lost altogether. Understanding how these double-branched limbs evolved has been a major question for scientists.

A long-extinct group of arthropods, the anomalocaridids, is considered central to the answer. The youngest known anomalocaridids are 480 million years old, and all of them looked quite alien: They had a head with a pair of grasping appendages and a circular mouth surrounded by toothed plates. Their elongate, segmented bodies carried lateral flaps that they used for swimming. Until now, it was believed that anomalocaridids had only one set of flaps per trunk segment, and that they may have lost their walking legs completely.

But the recent discovery of Aegirocassis benmoulae tells another story. The new animal shows that anomalocaridids in fact had two separate sets of flaps per segment. The upper flaps were equivalent to the upper limb branch of modern arthropods, while the lower flaps represent modified walking limbs, adapted for swimming. Furthermore, a re-examination of older anomalocaridids showed that these flaps also were present in other species, but had been overlooked. These findings show that anomalocaridids represent a stage before the fusion of the upper and lower branches into the double-branched limb of modern arthopods.

"It was while cleaning the fossil that I noticed the second, dorsal set of flaps," said Van Roy, who spent hundreds of hours working on the specimens. "It's fair to say I was in shock at the discovery, and its implications. It once and for all resolves the debate on where anomalocaridids belong in the arthropod tree, and clears up one of the most problematic aspects of their anatomy."

Read more at Science Daily

Extinct Baby Woolly Rhino Remains Found in Siberia

The remains of a baby woolly rhino that roamed the Earth at least 10,000 years ago have been discovered in a frozen riverbank in Siberia, researchers said.

The rhino calf, nicknamed "Sasha" after the hunter and businessman who found it, is the only complete young specimen of the extinct species ever found, according to scientists at the Yakutian Academy of Sciences in Russia, to whom the creature was donated for study.

The researchers hope to extract DNA from the specimen to determine its placement on the mammal family tree.

"The newly found is about 1.5 meters long [4.9 feet] and 0.8 meters high [2.6 feet]," said study researcher Albert Protopopov, head of the mammoth fauna studies department of the Yakutian Academy of Sciences in Russia, as translated by Olga Potapova, the collections curator and manager at the Mammoth Site of Hot Springs, South Dakota. By contrast, adults of this species could reach up to 15 feet (4.5 m) long and 6 feet (1.9 m) high at the shoulders, Protopopov said.Since the 18th century, the remains of only a few adult woolly rhinos have been discovered. Two complete bodies without hair were found in Staruni in what is now Ukraine, and a headless, frozen mummy was found in eastern Siberia, Potapova said. Woolly rhinos were depicted in late Paleolithic cave paintings in Western Europe, which add to scientists' knowledge of what the animals looked like, she added.

But the remains of rhino calves are very rare and fragmented, and little to nothing is known about the young animals, Protopopov told Live Science, via Potapova. Woolly rhinos likely had very high infant mortality — "that’s why is a very lucky find for us," he said.

The new remains are from a very young rhino, probably between 3 and 4 years old, said fellow researcher Evgeny Maschenko, of the Paleontological Institute in Moscow, as translated by Potapova.

"The young rhino mummy was covered by thick hair" and had two fist-size horns that were tightly attached to its skull, Maschenko said. Based on the size of its horns, Sasha had probably already been weaned from its mother, but it's not clear whether the calf was a male or female, he added.

Woolly rhinoceroses (Coelodonta antiquitatis) first appeared some 350,000 years ago during the Pleistocene epoch, which lasted from 2.59 million to 11,700 years ago. The animals fed on mostly low-growing herbaceous vegetation, and were widely found in the mammoth steppe, a vast cold and dry region spanning from Spain in the west to eastern Siberia in the east, and from subarctic latitudes in the north to the Mediterranean, southern Siberia and northern China in the south.

Woolly rhinos lived at the same time as, and shared a habitat with, woolly mammoths, but the two species are not related. The woolly mammoth is a cousin of the modern Asian elephant, whereas the woolly rhino is most closely related to the modern rhino, Potapova said.

Woolly rhinos went extinct about 10,000 years ago. Some scientists believe overhunting was the cause, but the more likely culprit is climate change, which caused the disappearance of the animals' food sources and habitat, researchers said. Unlike other large mammals of the time — such as woolly mammoths, steppe bison, cave lions and native horses — woolly rhinos may not have been able to cross the land bridge now occupied by the Bering Strait, because they were unable to adapt to the tundra climate, the researchers said.

If the researchers can obtain DNA from Sasha, they plan to sequence the animal's genome. This would allow scientists to identify the rhino's closest relatives, and determine whether there were one or two species of woolly rhino in the Late Pleistocene, Protopopov said.

Read more at Discovery News

World's Oldest Pretzel Found in Germany

German archaeologists announced this week they have discovered what could be the world’s oldest pretzel.

Unearthed during a large excavation on the “Donaumarkt” in Regensburg, an area nearby the Danube which was destroyed in the 1950-60s, the charred pretzel fragments are believed to be 250 years old. They were recovered beneath a floor in a structure long known to be a bakery.

“We found the remains of two pretzels, a piece of bread shaped like a croissant and three small bread rolls,” Silvia Codreanu-Windauer, of the Bavarian State Department of Monuments and Sites, told Discovery News.

German archaeologists announced this week they have discovered what could be the world’s oldest pretzel.

Unearthed during a large excavation on the “Donaumarkt” in Regensburg, an area nearby the Danube which was destroyed in the 1950-60s, the charred pretzel fragments are believed to be 250 years old. They were recovered beneath a floor in a structure long known to be a bakery.

“We found the remains of two pretzels, a piece of bread shaped like a croissant and three small bread rolls,” Silvia Codreanu-Windauer, of the Bavarian State Department of Monuments and Sites, told Discovery News.

It is believed pretzels were invented sometime between the 5th and 6th centuries by monks who twisted leftover strips of dough to look like arms crossed in prayer.

Even though they are 250 years old, the pretzel fragments are similar to today’s product.

“They look the same. The fragments are just a little bit smaller because of the carbonizing process,” Codreanu-Windauer said.

The baked goods represent the first archaeological proof of a typical Bavarian bakery assortment.

Read more at Discovery News

Explorer Beams Out Images of Long-Lost Japan Battleship

 The shattered wreck of a Japanese World War II battleship was shown lying on a Philippine seabed in startling detail Friday, as the first images emerged from the historic discovery by Microsoft co-founder Paul Allen.

American billionaire and explorer Allen announced the find of the Musashi -- one of the most sophisticated battleships ever built -- in the Sibuyan Sea in the central Philippines eight days ago, after a high-tech mission lasting eight years.

It was the latest of many searches for the ship, with the find coming some 70 years after it was sunk by US forces in World War II.

Giant gun turrets and propellers, a torpedo-damaged hull and a plane wing resting on silt were among the images beamed live by an unmanned mini-submarine from about a kilometer (0.6 miles) below the water's surface.

"We think we're conveying something to the world which is significant. It also teaches us about the past and what happened," said Yannick Olson, captain of Allen's yacht, from where the mini-sub was being directed.

Excited historians have likened the discovery to finding the wreck of the Titanic, the famed British passenger liner that sank in the North Atlantic Ocean after colliding with an iceberg in 1912.

The wreck of the Musashi, partially buried and scattered over a large debris field, is also the presumed graveyard of some of the more than 1,000 crew members killed in the battle.

However, the video streamed on Allen's website showed no human remains.

"It's quite clear it didn't land on the bottom in one piece," Olson said. "The destruction was total."

Barnacles and light-colored coral clung to the broken hull, propellers and anchor of the 263-metre (863-foot) ship, as well as on corroded sections of range-finders for the ship's guns, their armor plating ripped off.

An eel was seen crawling out of the remains of the warship's aeroplane catapult, with instructions in Japanese script written on it, while two pink fish patrolled outside the hull.

The worn remains of the chrysanthemum seal of the Japanese emperor remained on the ship's bow.


Read more at Discovery News

The Spanish Fly Is Real, and It’s Ridiculously Dangerous

The Spanish fly won't get you horny, but it will get you dead.

In 1869, a French military doctor got what we can confidently say was one of the stranger cases of his career. A group of soldiers were complaining of weakness, stomach problems, dry mouths, and aggressively persistent erections. The problem, it seemed, was that they’d been eating frogs that had themselves been eating the fabled Spanish fly.

In reality, it’s not a fly. It’s actually one of the 3,000 species of so-called blister beetles. And the bug’s defensive secretion, cantharidin, has been used as an “aphrodisiac” since ancient times. Yeah, it doesn’t actually work, unless your idea of sexy is dying a horrible death. Still, throughout history men often laced women’s drinks with it (alleged rapists like Bill Cosby still joke about it) or took it themselves.

Anger one of these insects and it’ll leak cantharidin right out of its leg joints. Do something dumb like touch it and that cantharidin will make your skin bubble up into nasty yellow blisters (or, like this poor bastard, you could slap one that’s landed on your neck). Do something even dumber like eat the stuff and it may be your last meal—it’s as powerful as cyanide and has no antidote. It strips away the lining of your stomach and you bleed internally. As your kidneys struggle to purge the cantharidin, it inflames your urinary tract, giving you what you think is an erection, but is actually just severe inflammation.

One particularly strange story of cantharidin poisoning comes from a fishing trip gone terribly awry. The fisherman, for whatever reason, had the idea that his prey would be attracted to cantharidin, so he mixed some of the stuff up with water in a bottle, using his thumb to plug the hole. Unfortunately, he just so happened to prick that same thumb, then suck on it. A half hour later, he started vomiting. Then came the diarrhea, which continued for the two days he delayed going to the hospital. Once there, weakness and a racing heart set it, and just five hours later, he perished.

It’s not just humans that fall victim to the blister beetle’s incredible toxicity. Horses in particular are highly susceptible to the toxin, according to entomologist Dan Marschalek of San Diego State University. “What will happen is that there are some species that feed on alfalfa, and they’ll get incorporated into the hay. And even if the beetles are dead, that toxin still remains within the dead body.” Horses gobble up the alfalfa and the hitchhiking beetles, begin bleeding internally, and drop dead. Cows and sheep seem to be less susceptible to the poison.

That’s cantharidin-packed blood leaking out of the Meloe campanicollis’ leg joint. And the red and blue on its back aren’t natural spots—they’re fingernail polish (the specimen was the subject of a marking study).

You’d think that with such a reputation surrounding blister beetles, the initiated would go out of their way to avoid cantharidin, and you’d certainly think that it has no place in medicine. But in fact physicians have used it for thousands of years—in varying degrees of ridiculousness. Not that I should have to tell you, but no, cantharidin won’t cure rabies as some ancients believed. It is, however, effective at treating warts and skin bumps manifested by the molluscum virus, and has long been used in modern medicine (when applied properly it apparently isn’t even all that painful). And, again, not that I should have to tell you, but our lawyers would probably appreciate it if I mentioned that under no circumstances should you self-medicate by rubbing a blister beetle on your warts.

You’re welcome, lawyers.

The Cold-Blooded Antics of the Baby Blister Beetle
Only male blister beetles synthesize cantharidin, but out of the kindness of their hearts, they’ll transfer some to the females when they come together to mate. This is known as a nuptial gift, and all kinds of insects do it, though it’s typically a nutritious package, not a weaponized one. The males of some species will transfer an energy-rich fluid, while others present the females with prey items. The most extreme nuptial gift of all, though, is when the male himself turns into the gift as the female simply devours him. So he does not live happily ever after. Or at all, for that matter.

OK, maybe male blister beetles aren’t transferring the cantharidin out of the kindness of their hearts. Like with species that exchange nutritious packages, this is a male’s strategy to ensure the survival of his offspring. “The female will use the cantharidin to coat the eggs,” says Marschalek, “so it’ll provide some protection for the eggs before they develop.” Thus can the male help ensure the survival of his young without having to directly care for the ingrates.

Epicauta pensylvanica, a species common in the eastern US. Some blister beetles mate by mounting, while others take this bum-to-bum approach.

Once the eggs hatch into tiny larvae, though, the young don’t need no help surviving. Their mother will have laid them at the base of a plant, and the clever little things make their way up the stem en masse and get into flowers. When a solitary species of bee lands, the tiny larvae swarm onto it. Somehow they can tell the difference between male and female bees, which is important considering they’re trying to hitch a ride back to a nest, which only females maintain. If they get a female, great—it’s straight to the nest. But if they get a male, they have to pray that he’s about to mate with a female. When that happens, the larvae swarm from him onto the female to get to the nest. There they’ll first devour her supply of pollen that she intended to save for her own kids. Once she lays her eggs, they’ll eat those too, and if those eggs manage to hatch into larvae, they’ll eat those too. Unfortunately for momma bee, they’re positively insatiable.

But there are a couple species of blister beetle whose larvae get even cleverer. When they climb up the plant they don’t look for flowers, but instead form into a squirming mass on the stem (see the BBC video on it below). “So there’ll be tens to hundreds of these small larvae in a ball, and so kind of visually that mimics a bee,” says Marschalek. “But they’re also producing some kind of chemical cue to attract the male bees, and so they’ll bring the bee in, they’ll grab onto it, and then do the transfer to a female while the bees are mating.” Then it’s off to the bee buffet.

Read more at Wired Science

Bat Species Warm 'Sleep' Upends Hibernation Concept

Two sub-tropical bats found in caves in Israel challenge key assumptions about hibernation, according to Professor Noga Kronfeld-Schor and doctoral student Dr. Eran Levin, from Tel Aviv University (TAU).

Rhinopoma microphyllum and the R. Cystops, two species of mouse-tailed bat, have been documented by the researchers hibernating in their country's Great Rift Valley caves -- doing so in consistently warm surroundings, at consistently warm body temperatures.

A variety of mammals dodge the cold of winter by hibernating anywhere from three to nine months out of the year. But the survival tactic is usually only seen in very cold temperatures, whereas the bats observed by the TAU scientists were hibernating in a cave in the Middle East, where the temperature was a consistent 68 degrees F.

What's more, the bats did something else distinctive: they managed the trick of hibernating while maintaining a high body temperature, something also against the grain for a hibernator. Typically a mammal's body temperature stays very low throughout hibernation, the better for the animal to expend as little energy as possible so they can lay low until warmer weather arrives.

The bats indeed used very little energy, but they did so even as their skin temperatures averaged about 71 degrees F.

"Hibernation in mammals is known to occur at much lower temperatures, allowing the animal to undergo many physiological changes, including decreased heart rate and body temperature," explained Kronfeld-Schor, chair of the department of zoology in TAU's faculty of life sciences.

"But we have found these bats maintain a high body temperature while lowering energy expenditure levels drastically," he said. "We hypothesize that these caves, which feature a constant high temperature during winter, enable these subtropical species to survive on the northernmost edge of their world distribution."

The two mouse-tailed bats studied by Kronfeld-Schor and Levin hibernated from October through February, existing in a barely conscious state, drawing breath only once every 15 to 30 minutes.

Even when other bat species in the same cave were active, these two bats took nothing to eat or drink, the scientists said. They also spent long periods holding back exhalation.

Before the pair's discovery, the temperate Middle East wasn't considered the most likely place to find mammals hibernating. Indeed, "until recently, it was believed that there was no mammalian hibernation in Israel, apart from hedgehogs," Kronfeld-Schor said.

"But this discovery leads us to believe there may be others we don't know about," he added. "Scientists haven't been looking for incidences of hibernation at warm temperatures. This is a new direction for us."

New also, the scientist noted, is that hibernating animals are capable of conserving energy without lowering their body temperatures. "These bats exhibited dramatic metabolic depression at warm body temperatures in the hottest caves in the desert," Kronfeld-Schor said.

Read more at Discovery News

Artificial Photosynthesis Closer to Creating Fuel

Solar and wind power have one thing in common besides being renewable: When the sun isn’t shining or the wind isn’t blowing, they don’t generate electricity. But artificial photosynthesis may someday help change that.

Battery storage is being developed as a way to feed renewable power onto the power grid regardless of the weather or the time of day, to lessen reliance on carbon-emitting fossil fuels. But some scientists are looking to plants and trees for another solution — using a man-made leaf that can turn solar energy into fuel in the form of liquid sugars or carbohydrates.

In nature, plants use energy from the sun and convert it into chemical energy to be used later. Scientists at Caltech think they have discovered a missing link in the development of an artificial version of that process, according to a paper published this week in the Proceedings of the National Academy of Sciences.

“There are a lot of things we should be doing today that if we really wanted to lower carbon emissions we’d do already,” Nate Lewis, professor of chemistry at Caltech and co-author of the paper, said. “This isn’t one of those. This is the bridge. If you want to bring on renewables, you’ve got to find a way to store carbon-free power and got to get high-energy-density transportation fuels carbon-neutral. We have to be ready with technology that can do both of those things.”

Artificial photosynthesis is the leading candidate for that job, he said.

“The idea is that we want to take sunlight, water and potentially CO2 as the inputs and make fuel as the output,” Lewis said.

Other studies, including a Harvard University study published in February, have shown the promise of artificial photosynthesis through the use of a “bionic leaf” as a possible energy source.

That study shows how an artificial leaf could be used with a special bacterium to produce a liquid “solar fuel.”

The Caltech team looked at a different aspect of similar technology to make liquid fuel.

For that, his team at the Joint Center for Artificial Photosynthesis at Caltech has shown how a special membrane could make artificial photosynthesis work without the risk of explosion from the volatile gases involved in the process.

Artificial photosynthesis requires two light-sensitive electrodes: One oxidizes water molecules to form oxygen gas, protons and electrons, while the other electrode combines protons and electrons to generate hydrogen gas. A barrier must separate the two electrodes so the gas can enter a pipeline without exploding.

The team discovered that a nickel oxide film that effectively separates the electrodes is the key.

Lewis said that discovery shows that artificial photosynthesis can work, but more research needs to be done to perfect the technology, which is likely to mature over the next decade or so.

“The availability of artificial photosynthesis technology could help mitigate climate change only if it is widely and actively adopted as an energy strategy at the international level,” said Dimitrios A. Pantazis, a chemist at the Max Planck Institute for Chemical Energy Conversion in Germany, adding that the necessary technology will appear only if countries can get fossil fuel consumption under control.

There are also enormous challenges that aren’t likely to be overcome anytime soon, including building new infrastructure to store, transport and use solar fuel, he said.

Production challenges of making artificial leaves haven’t been solved, either, and the Caltech team’s membrane may be especially prone to problems, said Daniel Nocera, professor of energy at Harvard University’s chemistry department.

Lewis said his team showed that the membrane it used can work for awhile.

“Of course, if the coating/catalyst cracks, the system will be shot,” Nocera said. “So, long-term issues still remain. But it is a nice lab experiment.”

When will commercial-scale artificial photosynthesis technology start reducing greenhouse gas emissions?

Read more at Discovery News

Teen Forced Into Chemotherapy Now in Remission

A Connecticut teenager removed from her family for her own safety after refusing to undergo cancer treatment last year is now in remission, according to her doctors.

The 17-year-old, known as Cassandra C, was taken into state custody in January and forced to undergo chemotherapy for Hodgkin’s lymphoma after refusing treatment in favor of unproven alternative medicines. According to an NBC News story, “Court documents show DCF [Connecticut's Department of Children and Families] took custody of her when she ran away from home after two days of chemotherapy and missed medical appointments.”

Her family fought to retain custody of her, and the case went to the Connecticut’s Supreme Court which ruled that Cassandra and her parents could not refuse medical treatments.

At the time of the Supreme Court decision, NBC News noted that “Doctors at the Connecticut Children’s Medical Center in Hartford say the treatment would give Cassandra an 85 percent chance of survival. Without treatment, the doctors said there was a near certainty of death within two years.”

The fact that Cassandra was a minor when diagnosed likely saved her life; had she been 18 and legally an adult the courts could not have compelled her to seek medical treatment.

Cassandra’s case was watched closely by medical ethicists and civil liberties organizations such as the American Civil Liberties Union, which filed an amicus brief on behalf of Cassandra’s family. As NBC News noted, “Assistant Public Defender Joshua Michtom, who is representing Cassandra, said the case marks the first time the state Supreme Court has considered the ‘mature minor doctrine’ recognized by several other states. The doctrine generally allows court hearings for minors 16 and 17 years old to prove that they are mature enough to make medical decisions for themselves.”

Though there are cases of parents who refuse to take their minor children to doctors because of religious reasons or health beliefs, this case was different. Cassandra and her family apparently did not object to all medical treatment, nor on religious grounds, but because she he did not want to “put poison into her body.” Instead Cassandra sought alternative, unproven treatments with fewer side effects — and no scientific evidence of effectiveness.

Read more at Discovery News

Enceladus Has Potentially Life-Giving Hydrothermal Activity

Saturn’s icy moon Enceladus is showing definite signs of hydrothermal activity — similar activity that is found along deep sea vents on Earth where water is heated and minerals are formed. Known to have a sub-surface ocean of salty water, the new findings described in two recent papers have boosted the moon’s life-giving potential.

“These findings add to the possibility that Enceladus, which contains a subsurface ocean and displays remarkable geologic activity, could contain environments suitable for living organisms,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate in Washington D.C. “The locations in our solar system where extreme environments occur in which life might exist may bring us closer to answering the question: are we alone in the universe.”

Enceladus is already known for its famous geysers blasting water vapor from beneath the moon’s icy crust. Long fractures in the moon’s south pole allow liquid water to escape into space, a sure sign that some kind of heating process is going on deep inside the icy world.

Now, through the analysis of minerals contained within the water vapor detected during flybys of NASA’s Cassini mission, the nature of this heated water has been revealed. And it’s great news if you happen to be a deep-sea dwelling microbe.

Hydrothermal Hothouses

On Earth, hydrothermal vents on ocean floors are hothouses of chemical reactions, providing a vital energy resource to marine life. Often, the lifeforms found at the bottom of oceans do not require sunlight to survive; they have evolved next to these hydrothermal vents, thriving in the dark with the energy the vents provide.

Now, through new analysis of Cassini data, scientists writing in the journal Nature have discovered microscopic grains of silica (the mineral quartz that is found on Earth) and related what that means in laboratory experiments. This discovery indicates that hot water, at a temperature of at least 194 degrees Fahrenheit (90 degrees Celsius), containing dissolved minerals from the moon’s core has been forced through cooler layers of water. Tiny rock grains then form during this process.

“It’s very exciting that we can use these tiny grains of rock, spewed into space by geysers, to tell us about conditions on — and beneath — the ocean floor of an icy moon,” said lead author Sean Hsu, a postdoctoral researcher at the University of Colorado at Boulder.

The small size of the grains of minerals found in Enceladus’ water vapor hints at the speed at which they are formed. The largest grains were only 6 to 9 nanometers in size, showing that they must have formed very quickly as the hot water the minerals were dissolved in came into contact with the comparatively cooler layers of water at the bottom of the moon’s ocean. The distance from seafloor to outer space is around 30 miles, so from formation to release, the grains would have spent only a few months to a few years in transit otherwise they would have had time to grow much larger.

This first line of evidence of hydrothermal activity suggests Enceladus has a porous, rocky core where liquid water from the ocean has the freedom to percolate through the core, forming water-borne mineral particles.

Methane Clues

In a second paper published by the journal Geophysical Research Letters, researchers investigating the curious abundance of methane in Enceladus’ plumes also suggest hydrothermal activity is at play.

In the pressures associated with Enceladus’ deep ocean, the team was investigating how methane gas is likely locked inside water ice crystals called clathrates. According to the authors, the Enceladus clathrate-forming process should be so efficient that the ocean is almost entirely depleted of methane. If this is the case, why is Cassini seeing an abundance of methane in the plumes?

There are two possibilities. The first is that the clathrates in the ocean are being dragged to the surface by the erupting plumes, venting the methane as they go. The second possibility is that hydrothermal activity is creating more methane than the clathrate-formation process can lock away. Although both proceses are likely occurring, the fact that another study has found rock minerals associated with hydrothermal activity suggests there may also be a hydrothermal answer to the methane puzzle.

“We didn’t expect that our study of clathrates in the Enceladus ocean would lead us to the idea that methane is actively being produced by hydrothermal processes,” said Alexis Bouquet, a graduate student at the University of Texas at San Antonio and lead author of the second paper.

On Earth, hydrothermal vents heated by volcanic activity deep within our planet’s core provide the necessary ingredients for life to form at the bottom of the ocean, devoid of light. On Enceladus, with a core heated by Saturn’s tidal squeezing, it seems an identical process is occurring — water loaded with minerals is heated and rocky particles condense from the mix.

Read more at Discovery News

Florida Isn't the Only State to 'Ban' Climate Change

Florida, one of the states most susceptible to the effects of climate change and sea-level rise, verbally banned state environmental officials from using the term “climate change,” an investigation revealed. But the Sunshine State isn’t the only U.S. state that has attempted to “outlaw” climate science.

North Carolina, Louisiana and Tennessee have all passed laws that attempt to cast doubt on established climate science in boardrooms and classrooms.

The reality of climate change due to human activity has been widely accepted by climate scientists, and some experts worry that attempts to deny the science could prevent states from preparing for sea level rise, extreme weather and other effects of a warming planet.

In an investigation published yesterday (March 8), the Florida Center for Investigative Reporting (FCIR) found evidence of an unwritten policy that banned officials at the state’s Department of Environmental Protection (DEP) from using specific terms related to climate change in official communications, emails or reports.

“We were instructed by our regional administrator that we were no longer allowed to use the terms ‘global warming’ or ‘climate change,’or even ‘sea-level rise,’” Kristina Trotta, a former DEP employee who worked in Miami, told the FCIR. “Sea-level rise was to be referred to as ‘nuisance flooding,’” Trotta added.

Other former employees confirmed the existence of the unofficial policy, which went into effect after Florida Gov. Rick Scott took office in 2011 and appointed Herschel Vinyard Jr. as director of the DEP. Scott, who was re-elected in November, has repeatedly stressed that he is not convinced climate change is caused by human activity, the FCIR reported.

But long before Florida unofficially banned these climate-related terms, other states passed laws attempting to limit the influence of climate change on land policies and education.

In 2012, North Carolina passed legislation banning the state from basing coastal policies on the latest predictions of sea level rise, ABC News reported. Democratic Gov. Bev Perdue allowed the bill, known as House Bill 819, to become law by not taking action against it.

The law was a response to a prediction by the state’s Coastal Resources Commission   that sea levels could rise by 39 inches (99 centimeters) in the next century. The prediction raised fears that home insurance rates would increase and coastal development would slow.

Proponents of the law said the prediction is based on incomplete information, but critics accused the state of denying climate science.

According to the U.S. Geological Survey, sea levels in North Carolina and other “hotspots” along the East Coast between North Carolina and Massachusetts are rising at three to four times the rate worldwide.

Meanwhile, other states had been passing laws of their own to curb the influence of climate change in education. In 2012, Tennessee passed a law to allow teachers to present alternative theories to climate change and evolution, making it the second state, after Louisiana, to pass such a law.

Read more at Discovery News

Neanderthal Claw Necklace (or Bracelet) Found

Remains of a necklace or bracelet made by Neanderthals have been found in Croatia.

The artifacts, described in the latest issue of the journal PLOS ONE, add to the growing body of evidence that Neanderthals had their own rich culture and meaningful symbols long before Homo sapiens came to Europe.

“It’s really a stunning discovery,” lead author David Frayer of the University of Kansas said in a press release. “It’s one of those things that just appeared out of the blue. It’s so unexpected and it’s so startling because there’s just nothing like it until very recent times to find this kind of jewelry.”

Perhaps proving that everything old is new again, some traditional cultures today still wear this type of jewelry, except it’s usually made out of different materials, such as shells.

In this case, the jewelry components were claws of white-tailed eagles. The claws bear multiple edge-smoothed cut marks, Frayer and his team determined, after studying the finds.

The claws, dated to 130,000 years ago, also appear to have been polished before they were likely strung and then worn on either the wrist or neck.

White-tailed eagles, also called “sea eagles,” are still around today. They are large birds of prey that are closely related to bald eagles.

The Neanderthals came from a site called Krapina. Frayer and his team believe that the eagles and their claws must have held a symbolic meaning for Neanderthals at the time. The precise meaning remains a mystery, though.

Read more at Discovery News

NASA to Launch Satellites into Powerful Magnetic Explosions

Magnetic reconnection is ubiquitous — wherever there’s a magnetic field there’s the potential for the field to ‘snap’, reconnect and, if the magnetic field is embedded in an energetic plasma, explode.

Although the physical phenomenon has been observed to occur in everything from the sun’s corona to the tokamaks inside experimental fusion reactors, scientists are not entirely clear what triggers it and why the result of reconnection is often highly energetic.

Tomorrow, NASA hopes to change that by launching a formation-flying group of probes into the Earth’s very own reconnection ‘laboratory’, the magnetosphere.

Countless pages of physics textbooks are devoted to the theory behind magnetic reconnection, but the science remains difficult to understand. The simple act of magnetic field lines crossing is often all it takes for reconnection to occur, but why does it often result in such an energetic reaction? Two very visible solar phenomena, solar flares and coronal mass ejections, are driven by magnetic reconnection — field lines break, reconnect and rapidly accelerate plasma through the corona, often generating powerful blasts of X-ray radiation.

At the opposite end of the scale, inside experimental fusion chambers on Earth, powerful magnetic fields are used to contain and control the plasma undergoing fusion. However, instabilities in the magnetic field cause small-scale reconnection events that can interrupt experiments.

“For many years, researchers have looked to fusion as a clean and abundant source of energy for our planet,” said Jim Burch of the Southwest Research Institute. “One approach, magnetic confinement fusion, has yielded very promising results with devices such as tokamaks. But there have been problems keeping the plasma contained in the chamber.

“One of the main problems is magnetic reconnection,” he said in a NASA news release. “A spectacular result of reconnection is known as the ‘sawtooth crash.’ As heat in the tokamak builds up, the electron temperature reaches a peak, then ‘crashes’ to a lower value. Some of the hot plasma escapes. This is caused by reconnection of the containment field.”

Unfortunately, these events cannot be properly studied as they occur over tiny volumes that are too small to be probed.

So rather than trying to catch reconnection in the act in the laboratory, Burch and his team have built a constellation of satellites that will be launched into the Earth’s very own reconnection factory on Thursday (March 12).

“Earth’s magnetosphere is a wonderful natural laboratory for studying this phenomenon,” he said.

Guided by GPS and flying in formation around 10 kilometers apart, the four Magnetospheric Multiscale (MMS) satellites will embed themselves in the magnetic environment surrounding our planet.

The Earth’s magnetosphere acts to deflect charged particles from the sun, but it is also shaped by the solar wind and the sun’s own magnetic field. Geomagnetic storms, for example, are ripples generated through the magnetosphere, often triggering reconnection events in the magnetosphere’s tail, that go on to accelerate solar plasma, injecting it into the Earth’s magnetic poles. Magnetospheric reconnection events therefore drive auroral activity at high latitudes.

But unlike the tiny scales impossible to measure in fusion reactors, reconnection zones in the magnetosphere are far bigger and MMS will be embedded inside the region to take high-resolution look at magnetic reconnection in action.

“After launch, the spinning spacecraft will unfurl their electromagnetic sensors, which are at the end of wire booms as much as 60 meters long,” says Craig Tooley, MMS Project Manager at NASA’s Goddard Space Flight Center in Greenbelt, Md. “When fully extended, the sensors are as wide as a baseball field.”

Read more at Discovery News

Could Nearby Dwarf Galaxy be a Dark Matter Factory?

A dwarf galaxy orbiting the Milky Way is humming with gamma rays, leading astronomers to hypothesize that it could be filled with annihilating dark matter particles.

Dark matter is thought to make up for 85 percent of all the mass in the known universe. By looking at the spin of galaxies and the interactions inside galactic clusters, an invisible type of matter exerts a powerful gravitational pull on local space. But because dark matter does not interact with normal (‘bayonic’) matter via the electromagnitic force, it cannot be seen and therefore its nature remains highly mysterious.

One leading hypothesis of the source of dark matter is that of weakly-interacting massive particles, or WIMPS. These particles have yet to be discovered, but if they are out there they could account for the bulk of the universal missing mass.

WIMPS, when they collide, are theorized to annihilate. One of the byproducts of this annihilation is energy in the form of gamma rays. But simply scanning the cosmos for sources of WIMP-generated gamma rays is a difficult task as there are many other phenomena out there that also generate gamma ray radiation.

That’s where dwarf galaxies come in.

Known gamma ray sources include black holes and pulsars, making the identification of annihilating WIMPs a precarious task. But ancient dwarf galaxies are known to lack a large number of these sources, making them key hunting grounds for the signature of dark matter. “They’re basically very clean and quiet systems,” said Savvas Koushiappas of Brown University in a press release.

“In the search for dark matter, gamma rays from a dwarf galaxy have long been considered a very strong signature,” he added. “It seems like we may now be detecting such a thing for the first time.”

Located only 98,000 light-years away, the dwarf galaxy Reticulum 2 is one of the closest dwarf galaxies found to date and it has become the focus of the dark matter search. Through the analysis of observational data from NASA’s Fermi Gamma-ray Space Telescope, Koushiappas and Carnegie Mellon University colleagues Alex Geringer-Sameth and Matthew Walker realized that Reticulum 2 was generating gamma rays at a rate far higher than any known gamma ray source.

“Something in the direction of this dwarf galaxy is emitting gamma rays,” said Geringer-Sameth, the study’s lead author. “There’s no conventional reason this galaxy should be giving off gamma rays, so it’s potentially a signal for dark matter.”

Seeking the nature of dark matter has been maddeningly difficult, so when a predicted signature of the annihilation of WIMPs in a dwarf galaxy right next door to the Milky Way is revealed, it’s understandable that some excitement, and guarded caution, is shown.

“The gravitational detection of dark matter tells you very little about the particle behavior of the dark matter,” said Walker. “But now we may have a non-gravitational detection that shows dark matter behaving like a particle, which is a holy grail of sorts.”

Read more at Discovery News

3,000 Skeletons Recovered at London Train Station Site

Archaeologists in London have begun digging up some 3,000 skeletons including those of victims of the Great Plague from a burial ground that will become a new train station, the company in charge said.

A team of 60 researchers will work in shifts six days a week over the next month at the Bedlam burial ground to remove the ancient skeletons, which will eventually be re-buried at a cemetery near London.

Crossrail, which is building a new east-west train line in London, said the dig near Liverpool Street station was being carried out on its behalf by the Museum of London's archaeology unit.

The company said in a statement that the bones would be tested to "shed light on migration patterns, diet, lifestyle and demography" of Londoners at the time.

"Archaeologists hope that tests on excavated plague victims will help understand the evolution of the plague bacteria strain," Crossrail said.

The Bedlam ground was used between 1569 and 1738 -- a period that spanned Shakespeare's plays, the Great Fire of London and numerous plague outbreaks.

The excavation is also expected to further uncover the remains of an ancient Roman road, where Crossrail said that several artifacts such as horseshoes and cremation urns have already been found.

The area was London's first municipal burial ground and was named after the nearby Bethlem Royal Hospital or "Bedlam" -- the world's oldest psychiatric institution, which has since relocated outside London.

The burial ground was used by Londoners who could not afford a church burial or who chose to be buried there for religious or political reasons.

Members of the Levellers, a 17th-century political grouping that advocated popular sovereignty and religious tolerance, are believed to be buried there.

Following excavation, constructors will build a new ticket hall for Crossrail's Liverpool Street station.

"The Bedlam burial ground spans a fascinating phase of London's history, including the transition from the Tudor-period City into cosmopolitan early-modern London," said Jay Carver, Crossrail lead archaeologist.

Read more at Discovery News

Alexander the Great-Era Treasure Found in Israeli Cave

A rare cache of jewelry and silver coins, minted during the reign of Alexander the Great, has been discovered in a stalactite filled cave in northern Israel, the Israel Antiquities Authority (IAA) announced on Monday.

The 2,300-year-old treasure was found by three members of the Israeli Caving Club who wriggled through a narrow passage at the entrance of the stalactite cave and wandered inside for several hours.

Stashed inside a niche, one of the spelunkers, Hen Zakai, spotted two ancient silver coins.

On one side of the coins was an image of Alexander the Great, while the other side portrayed an arm raised Zeus sitting on his throne.

The archaeologsts believe the coins had been minted in the late fourth century B.C. at beginning of the Hellenistic Period during the reign of Alexander the Great.

Alongside the coins, the spelunkers found the remains of a cloth pouch with three rings, four bracelets, two decorated earrings, three other earrings, probably made of silver, a small stone weight, and a clay oil lamp.

Dating from the Hellenistic period, the lamp contained some agate stones that were part of a string of beads.

“The valuables might have been hidden in the cave by local residents who fled there during the period of governmental unrest stemming from the death of Alexander,” the IAA said in a statement.

At that time, the Wars of the Diadochi broke out in Israel between Alexander the Great’s successors who fought for the control of the king’s empire after his death in 323 B.C.

“Presumably the cache was hidden in the hope of better days, but today we know that whoever buried the treasure never returned to collect it,” the IAA said.

As archaeologists of the Israel Antiquities Authority this week-end entered the cave, they discovered evidence of human habitation that occurred there over extended periods, from the Chalcolithic period 6,000 years ago to the Hellenistic period approximately 2,300 years ago.

Numerous pottery vessels were discovered in the cave and some even merged with the limestone sediments.

“The finds in the cave will allow the researchers –- archaeologists and geologists alike –- to accurately date both the archaeological finds and the process of stalactite development,” the IAA said.

The treasure trove, which promises to shed light on the lives of ordinary people in Israel during the late 4th century BC, follows another significant finding. Last month amateur scuba divers stumbled across a trove of nearly 2,000 gold coins that sat on the bottom of the Roman-era port of Caesareafor about 1,000 years.

Read more at Discovery News

The Milky Way May be 50 Percent Bigger Than Thought

A ring-like filament of stars wrapping around the Milky Way may actually belong to the galaxy itself, rippling above and below the relatively flat galactic plane. If so, that would expand the size of the known galaxy by 50 percent and raise intriguing questions about what caused the waves of stars.

Scientists used data collected by the Sloan Digital Sky Survey to reanalyze the brightness and distance of stars at the edge of the galaxy. They found that the fringe of the disk is puckered into ridges and grooves of stars, like corrugated cardboard.

“It looks to me like maybe these patterns are following the spiral structure of the Milky Way, so they may be related,” astronomer Heidi Newberg, with Rensselaer Polytechnic Institute in New York, told Discovery News.

She and colleagues suspect that a dwarf galaxy may have plunged through the disk of the Milky Way, setting off ripples, like a pebble falling into a pond.

Intruder galaxies also may have set up spiral wave patterns that later trigger star formation in the gas along waves, leading to spiral arms in galaxies.

Evidence that the so-called Monoceros Ring, located more than 65,000 light years from the center of the galaxy, actually is part of the Milky Way surprised Newberg, who was on a team that discovered the ring in 2002.

“We thought it was a tidal debris stream -- a dwarf galaxy that came in and spread itself out in this big ring. For 15 years, there’s been a controversy in the field where half the astronomers think it’s a tidal stream and half the astronomers think its something in the disk. I was in the stream camp,” Newberg said.

“What I was trying to do was find more evidence that it was streams. It took a very long time to get this result, partly because I had to change my whole my whole way of thinking. It now looks to me like it’s part of the disk,” she said.

Incorporating the ring into the map of the Milky Way expands the galaxy’s span from 100,000 light years to 150,000 light years, said astronomer Yan Xu, with the National Astronomical Observatories of China and a former visiting scientist at Rensselaer.

Light travels at 186,000 miles per second, so one light year is nearly 6 trillion miles.

Read more at Discovery News

Earth-Based Radar Unveils Venus' Mysterious Surface

These days if you look toward the west after sunset you’ll see a bright star that’s the first to appear in the sky – except it’s not a star at all, but our neighboring planet Venus. Covered in a dense layer of thick clouds, Venus not only reflects a lot of sunlight but also keeps its surface well concealed from visible-light observations.

But Venus’ clouds can be easily penetrated by radar, which was used by NASA’s Magellan spacecraft to map nearly all of its surface from orbit in the early 1990s as well as by the previous Pioneer and Soviet Venera spacecraft in the early 80s. While these missions provided incredibly detailed maps of Venus’ rugged terrain, they lack the ability to monitor for surface changes that may occur either suddenly or over short time frames — changes that could indicate ongoing geologic or weather-related processes unique to the planet.

Fortunately with the capabilities of powerful ground-based radar observatories, scientists have been able to create global maps of Venus from right here on Earth… no rockets necessary.

The image above was created by bouncing radar waves transmitted from the Arecibo Observatory in Puerto Rico off Venus and receiving their echoes at the 100-meter Green Bank Telescope in West Virginia. Such observations had been performed in 1988, 1999, 2001, and most recently in 2012, and the comparison allows researchers to hunt for clues to any surface activity.

“It is painstaking to compare radar images to search for evidence of change, but the work is ongoing,” said Bruce Campbell, Senior Scientist with the Center for Earth and Planetary Studies at the Smithsonian’s National Air and Space Museum in Washington, D.C. ”In the meantime, combining images from this and an earlier observing period is yielding a wealth of insight about other processes that alter the surface of Venus.”

Venus appears to have a relatively young surface covered in volcanoes as well as ridged and folded terrain, but with little to no tectonic activity. It’s not yet known what, if any,  geologic processes are currently in action on the Earth-sized planet today, although there are several volcanoes that are thought to have been active in the past couple million years and there have also been indications of possible volcanic outbursts observed in Venus’ atmosphere by ESA’s Venus Express.

A paper discussing the radar observations has been accepted for publication in the journal Icarus.

From Discovery News

Dog Sniffs Out Thyroid Cancer in Human Urine

A scent-trained dog was able to identify the presence or absence of thyroid cancer in human urine samples 88.2 percent of the time, a new study concluded.

The study out of the University of Arkansas for Medical Sciences (UAMS) gathered urine samples from 34 university thyroid clinic patients before they underwent a biopsy for suspicion of thyroid cancer.

Fifteen of those biopsies came back positive for thyroid cancer, while the remaining 19 were diagnosed as benign thyroid disease.

Enter Frankie, a male German shepherd mix that had been trained to recognize the scent of cancer in thyroid tissue. Frankie's sharp nose matched 30 out of 34 samples with their pathology diagnoses.

"Frankie is the first dog trained to differentiate benign thyroid disease from thyroid cancer by smelling a person’s urine," said study co-author Arny Ferrando, PhD at UAMS, in a release.

The study's senior investigator, Donald Bodenner, M.D., PhD, and chief of endocrine oncology at UAMS, said Frankie was only slightly less accurate than a standard thyroid biopsy with a needle. The dog's results offer the possibility of a cheaper, less invasive approach to diagnosis of the illness.

"Current diagnostic procedures for thyroid cancer often yield uncertain results, leading to recurrent medical procedures and a large number of thyroid surgeries performed unnecessarily," Bodenner explained. "Scent-trained canines could be used by physicians to detect the presence of thyroid cancer at an early stage and to avoid surgery when unwarranted."

Bodenner is not yet using canines in formal diagnoses outside of the study and said the next step will be to collaborate with Auburn University's College of Veterinary Medicine on an expansion of the scent-training program. The veterinary center plans to train two of its bomb-sniffing dogs to learn how to sniff out thyroid cancer, using samples from UAMS patients.

From Discovery News

Sheep Use Their Brains to Save Water

Sheep can reduce water loss by using a heat exchange system in their brain to cool down their blood, new research suggests.

The animals can save up to 80 percent of their daily water intake by using this system, said comparative physiologist, Dr Shane Maloney from the University of Western Australia.

Previous research has shown that sheep cool blood flowing into their brains using a structure called a carotid rete at the base of the brain. In this structure, the artery with blood flowing towards the brain divides into many fine blood vessels about 50 microns in diameter.

Heat in warm arterial blood can transfer out of these fine arteries into cooler venous blood that also passes by the rete. The venous blood, traveling down the body, has been cooled by evaporation in the sheep's nose.

The common wisdom has been that this cooling system is used to protect the sheep's brain from overheating. But a discovery in a study of South African black wildebeest in the 1990s didn't fit this theory.

While data loggers on the wildebeest showed that brain cooling was often switched on through the day, it was switched off when the animals were at their hottest when being chased by researchers in helicopters.

The fact they were hot but not using brain cooling led to the idea that brain cooling serves another purpose than protecting the brain.

An alternative theory suggests the system is actually a water-saving mechanism that works by cooling the hypothalamus, the body's thermostat, which sits at the base of the brain. When the hypothalamus is hot it triggers panting and sweating, which helps the animal to lose heat through evaporation.

"By switching on this brain cooling mechanism you lower the hypothalamic temperature and therefore you don't stimulate water use for thermoregulation (panting and sweating)," said Maloney.

Hot sheep

To test this hypothesis, Maloney and colleagues studied nine sheep, which naturally varied in the percentage of time they spent brain cooling during the day. When the hypothalamus is hot it triggers panting and sweating, which helps the animal to lose heat through evaporation.

"It was a bit like a Perth summer," said Maloney.

The sheep were deprived of water for the last five days (Maloney said sheep are known to go for a week without water). Throughout the experiment the researchers measured water loss, and brain and body temperatures every five minutes.

Their findings, reported in a recent issue of PLOS ONE, showed the longer an animal went without water, the more time it spent with its brain cooling system switched on.

This led to a greater difference between the animal's body and brain temperatures, and decreased the amount of water lost.

This is the first study of its kind to lend support to the hypothesis that brain cooling saves water, said Maloney.

He and colleagues calculate that a 50-kilogram sheep can save 2.6 liters of water a day, which is about 60 percent of its daily water intake, by using this system for 50 percent of the day.

For an animal using the system 80 percent of the day, this amount would increase to 3.54 liters a day, or 80 percent of normal water use.

Need for calm

Maloney said there is some evidence that the more stressed an animal becomes, the less amount of brain cooling it uses. Brain cooling is switched off by the sympathetic nervous system which in turn is triggered by stress.

This explains why the wildebeest in the 1990s South African study had their system switched off even though they were hot -- they were stressed due to being chased by helicopters. In this situation it was more important for them to lose heat than to save water.

"Whereas if you've got a nice calm docile animal ... they don't switch on the sympathetic nervous system, selective brain cooling is activated so they lower brain temperature and don't pant and sweat."

Read more at Discovery News

'Habitable' Super-Earth Might Exist After All

Despite having discovered nearly 2,000 alien worlds beyond our solar system, the profound search for exoplanets — a quest focused on finding a true Earth analog — is still in its infancy. It is therefore not surprising that some exoplanet discoveries aren’t discoveries at all; they are in fact just noise in astronomical data sets.

But when disproving the existence of extrasolar planets that have some characteristics similar to Earth, we need to take more care during the analyses of these data, argue astronomers from Queen Mary, University of London and the University of Hertfordshire.

In a paper published by the journal Science last week, the researchers focus on the first exoplanet discovered to orbit a nearby star within its habitable zone.

Revealed in 2009, Gliese 581d hit the headlines as a “super-Earth” that had the potential to support liquid water on its possibly rocky surface. With a mass of around 7 times that of Earth, Gliese 581d would be twice as big with a surface gravity around twice that of Earth. Though extreme, it’s not such a stretch of the imagination that such a world, if it is proven to possess an atmosphere and liquid ocean, that life could take hold.

And the hunt for life-giving alien worlds is, of course, the central motivation for exoplanetary studies.

But the exoplanet signal has been called into doubt.

Gliese 581d’s star, Gliese 581, is a small red dwarf around 20 light-years away. Red dwarfs are known to be tempestuous little stars, often generating violent flaring outbursts and peppered in dark features called starspots. To detect the exoplanet, astronomers measured the very slight frequency shift (Doppler shift) of light from the star — as the world orbits, it exerts a tiny gravitational “tug”, causing the star to wobble. When this periodic wobble is detected, through an astronomical technique known as the “radial velocity method,” a planet may be revealed.

Last year, however, in a publication headed by astronomers at The Pennsylvania State University, astronomers pointed to the star’s activity as an interfering factor that may have imitated the signal from an orbiting planet when in fact, it was just noisy data.

But this conclusion was premature, argues Guillem Anglada-Escudé, of Queen Mary, saying that “one needs to be more careful with these kind of claims.”

“The existence, or not, of GJ 581d is significant because it was the first Earth-like planet discovered in the ‘Goldilocks’-zone around another star and it is a benchmark case for the Doppler technique,” said Anglada-Escudé in a university press release. “There are always discussions among scientists about the ways we interpret data but I’m confident that GJ 581d has been in orbit around Gliese 581 all along. In any case, the strength of their statement was way too strong. If the way to treat the data had been right, then some planet search projects at several ground-based observatories would need to be significantly revised as they are all aiming to detect even smaller planets.”

The upshot is that this new paper challenges the statistical technique used in 2014 to account for the signal being stellar noise — focusing around the presence of starspots in Gliese 581′s photosphere.

Read more at Discovery News

We Need to Cast a Wide Net in Search for Alien Life

The hunt for signs of life on planets beyond our solar system should cast as wide a net as possible, some researchers stress.

Scientists scanning the atmospheres of exoplanets for gases produced by alien life should look for more than just oxygen, methane and the other familiar biosignatures that swirl about in Earth's air, Sara Seager and William Bain, both of MIT, wrote in a review article published on March 6 in the journal Science Advances.

"We know there will not be huge numbers of accessible planets," Seager told Space.com via email. "We want to make sure we do not miss any signatures, by trying our best to think outside the box. Oxygen is a great biosignature gas for Earth, but what are the chances it will be present on an exoplanet?"

To date, scientists have discovered more than 1,800 alien planets, most of which are very different from the worlds in our solar system.

"A specific, astonishing finding is that the most common type of planet in our galaxy are those with sizes between those of Earth and Neptune — a new class of planet that is neither terrestrial nor giant and one without an accepted theory for its formation," Seager and Bain wrote.

The diversity of exoplanets reinforces the very real possibility that alien life may be quite different from life on Earth, even if it inhabits a rocky world like our own. For example, what might live on "exo-Earths" whose atmospheres are dominated by molecular hydrogen instead of nitrogen and oxygen, as Earth's is?

"Although not yet observed, such planets are theoretically anticipated," Seager and Bains wrote.

Based on that reasoning, the researchers advocate an open-minded approach that would first identify "all viable biosignature gases, through a systematic, exhaustive study both from the view of molecules (there is no shortage) and of planetary environments and where the candidate biosignature gas molecules would accumulate and survive," they wrote.

"The near-term goal is to understand which molecules could be biosignature gases in atmospheres of exoplanets; a systematic table of chemicals made by life will give a starting point for predicting which molecules are stable, volatile and detectable remotely by space telescopes," Seager and Bains added.

Such a challenging project would likely take years to complete, Seager told Space.com. But researchers can spare the time because a systematic search for signs of life on alien worlds is probably at least a decade away, she and Bains wrote.

Scientists have already begun probing exoplanet atmospheres, using instruments such as the European Southern Observatory's Very Large Telescope in Chile.

And the effort will kick into higher gear soon, with the launch of NASA's Transiting Exoplanet Survey Satellite (TESS) in 2017 and the agency's James Webb Space Telescope (JWST) in 2018. TESS should find a number of nearby rocky planets whose atmospheres JWST can investigate. (Most exoplanets found to date, including those found by NASA's prolific Kepler space telescope, are too far away for such follow-up study.)

Massive ground-based telescopes, such as the Giant Magellan Telescope, Thirty Meter Telescope and European Extremely Large Telescope — which boast light-collecting surfaces 80 feet (24 meters), 98 feet (30 m) and 128 feet (39 m) wide, respectively — will boost the search further when they come online in the mid-2020s.

But Seager and many other experts say that the biosignature search really needs a space telescope with a mirror in the 33- to 39-foot (10 to 12 m) range — something like the proposed Advanced Technology Large-Aperture Space Telescope, or ATLAST.

Such an instrument could potentially analyze enough exoplanet atmospheres for researchers to do some number crunching. And that's important; the biosignature hunt will probably center on probabilistic inference because a slam-dunk detection will be difficult, if not impossible, to make, Seager and Bains wrote.

Read more at Discovery News

'Extinct' Bird Not Seen Since 1941 Suddenly Reappears

A conservation research team in Myanmar got a local call from the distant past when a bird long thought to be extinct suddenly chirped and begged to differ. And with that the Myanmar Jerdon's babbler (Chrysomma altirostre) was back in the birding phone book (for those who remember those big blocky books with phone numbers in them).

While surveying grasslands near the town of Myitkyo in May 2014, a team comprised of researchers from the Wildlife Conservation Society, Myanmar's Nature and Wildlife Conservation Division, and the National University of Singapore (NUS) heard the call of the long-lost babbler.

The team quickly played back a recording of the call, and soon an adult Jerdon's babbler, a bird not seen in Myanmar since 1941, came into view.

After that first encounter, it got even better. It was Jerdon's babblers aplenty, as over the next two days the team found the suddenly conspicuous birds in multiple locations near the first call.

A Jerdon's babbler is small and brown -- about the size of an ordinary house sparrow. It was first described in 1862 and was a common sight in Myanmar at the start of the 20th century, in wide-ranging grasslands around the Yangon region that were lost over time to agriculture and community development.

"The degradation of these vast grasslands had led many to consider this subspecies of Jerdon’s babbler extinct," explained Colin Poole, director of the Wildlife Conservation Society's efforts in Singapore. "This discovery not only proves that the species still exists in Myanmar but that the habitat can still be found as well."

The re-discovered Myanmar babbler is at this point considered one of three Jerdon's babbler subspecies found in river basins in South Asia (Terai and Sind are the other subspecies). But DNA samples and audio recordings obtained from the newfound birds should help researchers determine whether or not the Myanmar Jerdon's babbler should be a full species in its own right.

"Our sound recordings indicate that there may be pronounced bio-acoustic differences between the Myanmar subspecies and those further west, and genetic data may well confirm the distinctness of the Myanmar population," noted Frank Rheindt, an assistant professor in the NUS Department of Biological Sciences.

Read more at Discovery News

Far Flung Star Cluster Found at Milky Way's Edge

Astronomers in Brazil have discovered a cluster of stars forming at the edge of the Milky Way, according to a press release from the Royal Astronomical Society.

This is unusual because it was believed that stars generally take form closer to the center of our spiral-shaped galaxy, rather than from its swirling, spiral arms, which are thousands of light-years away. These two clusters of stars — named Camargo 438 and 439 — were seen in a cloud at the galaxy’s outskirts.

Denilso Camargo, an astronomer at the Federal University of Rio Grande do Sul in Porto Alegre, Brazil, led a team that analyzed data from NASA’s orbiting Wide-Field Infrared Survey Explorer (WISE) observatory. They zeroed in on dense clumps of gas in so-called giant molecular clouds(GMCs) that are known to generate stars. GMCs are mainly located in the inner part of the galactic disc.

The new star clusters lie about 16,000 light-years away from the main disk of the Milky Way galaxy. How did they form there? The scientists aren’t yet sure but Camargo theorizes that one of two scenarios could have led to the stars’ formation.

In the first scenario, called the “chimney model,” supernovas could have flung the gas and dust that formed the cloud out of the Milky Way. Another explanation is the material could have drifted in from outside the galaxy.

“Our work shows that the space around the Galaxy is a lot less empty that we thought,” said Camargo. “The new clusters of stars are truly exotic.”

Camargo’s team published their results in the journal Monthly Notices of the Royal Astronomical Society.

From Discovery News