Mar 23, 2013

Engineers Explain Physics of Fluids Some 100 Years After Original Discovery

Sunghwan Jung is a fan of the 19th Century born John William Strutt, 3rd, also known as Lord Baron Rayleigh. An English physicist, Rayleigh, along with William Ramsay, discovered the gas argon, an achievement for which he earned the Nobel Prize for Physics in 1904.

But it was Rayleigh's lesser-known discovery of a physical phenomenon in 1878 that was more intriguing to Jung. Some 135 years ago, Rayleigh wrote that two fluid jets or drops do not always merge into one body of liquid, a counter-intuitive topic or phenomena in physics that has since been studied in much detail, cited Jung, Virginia Tech assistant professor of engineering science and mechanics.

The significance today of this fact is that when noncoalescence takes place between two fluids, it might impact a variety of industrial and everyday processes such as fuel efficiency, ink jet printing, and the development of spray coatings.

New information on Rayleigh's verbal description of the collision of fluids now appears in a contemporary paper authored by Jung and Pavlos Vlachos, professor of mechanical engineering at Virginia Tech, and Navish Wadhwa, of Blacksburg, Va., a doctoral candidate in engineering science and mechanics.

The paper, accepted in Physical Review Letters, a peer-reviewed journal of the American Physical Society, is called "Noncoalescence in the oblique collision of fluid jets."

"In Rayleigh's original paper, he mentioned two things: drop bouncing on a liquid bath and jets bouncing. No pictures were given. Much work has been done in drop-bath bouncing, but no work has been done in bouncing jets except for a couple of demonstrations in textbooks. We are the first ones to rationalize the physical mechanism of bouncing jets," Jung explained.

In their experiments, the researchers studied two silicone oil jets bouncing off each other upon collision. Silicone oil is used in most experiments in order to avoid any surface contamination, Jung said, and it is often the base for hydraulic fluids or lubricants.

"Intuition tells us that two or more jets of the same fluid impinging into each other will readily coalesce to form a single mass of fluid, and are well-studied phenomena," Jung explained.

Velocity is key to bringing the two silicone oil jets into a single flow of liquid. Since these jets of fluid drag along air, considered to act as a cushion, the two jets will bounce off of each other. But when the speed of the flow is increased beyond a certain threshold, the air is no longer stable due to the high inertia of jets, and the liquid jets will coalescence, Jung added.

To attain fuel efficiency in space rockets, two different fuel fluids need to mix well to maximize the combustion.

"In our experiments, we showed they are able to bounce off each other and inhibit the mixing. However, in rocket fuel tanks, the fluids come out of the nozzles are a very high speed, so no bouncing happens in their cases," Jung said.

Read more at Science Daily

First Migration from Africa Less Than 95,000 Years Ago: Ancient Hunter-Gatherer DNA Challenges Theory of Early Out-Of-Africa Migrations

Recent measurements of the rate at which children show DNA changes not seen in their parents -- the "mutation rate" -- have challenged views about major dates in human evolution.

In particular these measurements have made geneticists think again about key dates in human evolution, like when modern non-Africans split from modern Africans. The recent measurements push back the best estimates of these dates by up to a factor of two. Now, however an international team led by researchers at the University of Tübingen and the Max Planck Institute for Evolutionary Anthropology in Leipzig, present results that point again to the more recent dates. The new study is published in Current Biology.

The team, led by Johannes Krause from Tübingen University, was able to reconstruct more than ten mitochondrial genomes (mtDNAs) from modern humans from Eurasia that span 40,000 years of prehistory. The samples include some of the oldest modern human fossils from Europe such as the triple burial from Dolni Vestonice in the Czech Republic, as well as the oldest modern human skeletons found in Germany from the site of Oberkassel close to Bonn.

The researchers show that pre-ice age hunter-gatherers from Europe carry mtDNA that is related to that seen in post-ice age modern humans such as the Oberkassel fossils. This suggests that there was population continuity throughout the last major glaciation event in Europe around 20,000 years ago. Two of the Dolni Vestonice hunter-gatherers also carry identical mtDNAs, suggesting a close maternal relationship among these individuals who were buried together.

The researchers also used the radiocarbon age of the fossils to estimate human mutation rates over tens of thousands of year back in time. This was done by calculating the number of mutations in modern groups that are absent in the ancient groups, since they had not yet existed in the ancient population. The mutation rate was estimated by counting the number of mutations accumulated along descendent lineages since the radiocarbon dated fossils.

Using those novel mutation rates -- capitalizing on information from ancient DNA -- the authors cal-culate the last common ancestor for human mitochondrial lineages to around 160,000 years ago. In other words, all present-day humans have as one of their ancestors a single woman who lived around that time.

The authors also estimate the time since the most recent common ancestor of Africans and non-Africans to between 62,000-95,000 years ago, providing a maximum date for the mass migration of modern humans out of Africa. Those results are in agreement with previous mitochondrial dates based on archaeological and anthropological work but are at the extreme low end of the dates sug-gested from de-novo studies that suggest a split of non-Africans from Africans about thirty thousand years earlier.

Read more at Science Daily

Mar 22, 2013

2,400-Year-Old Myths of Mummy-Making Busted

Contrary to reports by famous Greek historian Herodotus, the ancient Egyptians probably didn't remove mummy guts using cedar oil enemas, new research on the reality of mummification suggests.

The ancient embalmers also didn't always leave the mummy's heart in place, the researchers added.

The findings, published in the February issue of HOMO – Journal of Comparative Human Biology, come from analyzing 150 mummies from the ancient world.

Mummy history

In the fifth century B.C., Herodotus, the "father of history," got an inside peek at the Egyptian mummification process. Embalming was a competitive business, and the tricks of the trade were closely guarded secrets, said study co-author Andrew Wade, an anthropologist at the University of Western Ontario.

Herodotus described multiple levels of embalming: The elites, he said, got a slit through the belly, through which organs were removed. For the lower class, mummies had organs eaten away with an enema of cedar oil, which was thought to be similar to turpentine, Herodotus reported.

In addition, Herodotus claimed the brain was removed during embalming and other accounts suggested the heart was always left in place.

"A lot of his accounts sound more like tourist stories, so we're reticent to take everything he said at face value," Wade told LiveScience.

Mummy tales

To see how eviscerations really took place, Wade and his colleague Andrew Nelson looked through the literature, finding details on how 150 mummies were embalmed over thousands of years in ancient Egypt. They also conducted CT scans and 3D reconstructions on seven mummies.

The team found that rich and poor alike most commonly had the transabdominal slit performed, although for the elites evisceration was sometimes performed through a slit through the anus.

In addition, there wasn't much indication that cedar oil enemas were used.

Only a quarter of mummies had their hearts left in place. The removal of the heart seems to coincide with the transition period when the middle class gained access to mummification, so getting to keep the heart may have become a status symbol after that point, Wade said.

"The elites need some way to distinguish themselves from the people that they're ruling," he said.

And whereas Herodotus had suggested mummies had their brains removed and discarded, Wade and his colleagues found about a fifth of the brains were left inside the mummies' skulls. Almost all the others were pulled out through the nose, Wade's team described in another study detailed in the August 2011 issue of the same journal

After the evisceration, the bodies were rubbed down with a mild antiseptic such as palm wine. They were also covered with packets of natron, a naturally occurring salt, left to dry out for many days, packed with linen or wood shavings, and sometimes perfumed with scented items, Wade said.

Read more at Discovery News

Mega Volcanoes May Have Caused Mass Extinction

Massive volcanic eruptions may have led to the extermination of half of Earth's species some 200 million years ago, a new study suggests.

The release of gases from giant eruptions caused climate change that led to the End-Triassic Extinction, the widespread loss of land and sea species that made way for the rise of the dinosaurs, the research says. The new study, published today (March 21) in the journal Science, shows that a set of major eruptions spanning from what is now New Jersey to Morocco occurred very close to the time of the extinction.

Scientists suspected previously that such volcanic activity and the resultant climate change were responsible for this major extinction and at least four others. But researchers weren't able to constrain the dates of the eruptions and extinctions well enough to prove the hypothesis. The new study, however, dates the End-Triassic Extinction to 201.56 million years ago, the same time the volcanoes were blowing their tops.

The eruptions, known as the Central Atlantic Magmatic Province, began when the land on Earth was part of one giant supercontinent called Pangaea. They lasted more than 600,000 years and created a rift that became the Atlantic Ocean. The researchers studied lava from these flows in modern-day Nova Scotia, Morocco and New Jersey.

The previous dates for these eruptions had error margins of 1 million to 3 million years, but this study decreases those numbers by an order of magnitude, lead author Terrence Blackburn, a geologist at the Carnegie Institution for Science, told LiveScience.

The results showed that the oldest massive eruptions were in Morocco, followed by the ones in Nova Scotia 3,000 years later and then those in New Jersey another 10,000 years after that. Animal and plant fossils, along with pollen and spores from the Triassic era, can be found in sediment layers underneath the lava flows, but not in layers above them. This suggests the eruptions wiped out those species. The organisms that went extinct include eel-like fish called conodonts, early crocodile species, tree lizards and broad-leaved plants.

The evidence heats up

Blackburn and colleagues determined the age of the lavas based on their mineral content. When lava flows cool, the center regions remain hot, and some chemical elements, like the mineral zircon, fail to crystallize. Zircon incorporates large amounts of uranium, which radioactively decays into lead at a specific rate. By measuring the ratio of uranium to lead in lava rock, the scientists could figure out precisely when the eruptions occurred.

"Zircon's really the perfect time capsule,"Blackburn said.

A second piece of evidence supporting the role of volcanism comes from reversals in the Earth's magnetic field. The researchers found mineral grains from one of these reversals in the sediment layer that formed just before the extinction. Since the researchers found the same layers at every site they studied, the magnetic reversal serves as a marker for when the extinction occurred.

A final line of evidence comes from repetitive motions of the Earth. As the planet rotates on its axis, it wobbles around like a top, which causes the amount of energy it receives from the sun to fluctuate depending on the areas that are pointed directly at the sun. These fluctuations correspond to different climate conditions and occur on a regular interval. By using these intervals, the researchers were able to determine the age of fossil-containing sediments to within 20,000 years.

Warming the planet

The gigantic eruptions would have vented sulfates that reflected sunlight back into space, effectively cooling the planet for several thousand years. But the eruptions would also have released large amounts of carbon dioxide and other greenhouse gases, causing global warming. Many species wouldn't have been able to survive this dramatic shift in temperature and would have died out.

Read more at Discovery News

How Belief in Magic Spreads HIV in Africa

In many countries throughout the world belief in witches is common, and black magic is considered part of everyday life. A 2010 poll of 18 countries in sub-Saharan Africa found that over half of the population believe in magic. Witch doctors are consulted not only for healing diseases, but also for placing, or removing, curses or bringing luck.

One human rights activist in the small African country of Malawi, Seodi White, has been fighting for years to stem many traditional beliefs that help spread HIV, especially among poor and underprivileged women.

According to a CNN story, widows in some parts of southern Africa are expected to engage in unprotected sex in order to “cleanse” them. The belief is that the husband’s spirit will return otherwise, cursing the family.

“It’s a mindset issue,” White told CNN. “Even the widows, they’ve told me, ‘I don’t want to die, I don’t want a curse to come to my husband.’ They cry to be cleansed.”

Because this spiritual cleansing involves unprotected sex — just as sex with the deceased husband was assumed to have been — the widows are placed at increased risk of contracting HIV, which is endemic on the continent. There are even professional “cleansers” who charge high prices for their services, which the widows are often eager to pay to avoid a curse on their families.

In her book “The AIDS Conspiracy: Science Fights Back”, Nicoli Nattrass, director of South Africa’s AIDS and Society Research Unit, notes that there “is a rich South African literature suggesting that many black people believe that HIV may have spiritual causes, notably witchcraft attacks or loss of protection from ancestors through violating cultural taboos. As Adam Ashforth observes, ‘a disease or complex of symptoms better suited to interpretation within the witchcraft paradigm than AIDS would be hard to imagine.’ This is because the symptoms of AIDS — diarrhea, tuberculosis, and wasting are also the classic symptoms of poisoning through witchcraft. Thus, even where people accept that AIDS is caused by a sexually transmitted virus, suspicions of witchcraft may be retained as potential explanations for the ultimate reason behind the infection.”

Read more at Discovery News

Is Earth Rarer Than We Think?

“It is dangerous to assume life is common across the Universe.” These were the words of Charles Cockell at a Royal Society event on March 11 this year. While many people have freely debated the existence of extraterrestrial life, Cockell’s words carry a bit more weight than most. He happens to be the director of the U.K. Center for Astrobiology, based at the University of Edinburgh.

Bringing to mind the argument made by Fermi’s paradox — if the universe is teeming with life, where exactly is everyone? — this may seem at first to be a slightly pessimistic outlook. Evidently, however, the intention is not so much to pour cold water on the astrobiology research community, but to call into question our assumptions in the search for life elsewhere.

As Cockell went on to explain, ”People are encouraged to think that not finding signs of life is a ‘failure’ when in fact it would tell us a lot about the origins of life.”

In fact, this one single statement sums up what is potentially the biggest problem in astrobiology. We, quite simply, have no idea how life started. We don’t know where, how, when, or why molecules managed to replicate themselves into ever-more-complex forms and, eventually, living organisms.

Earth is the only example of a living planet that we have in the entire universe, and we don’t even understand it. Even now, biologists can still argue over what really constitutes a living thing, highlighted a couple of years ago by the discovery of giant viruses with genomes larger than some bacteria. And even if we did fully understand life here, there’s nothing to say it would be the same elsewhere.

Purely because we know life can exist on a planet like ours, with liquid water and at an appropriate distance from our star, we’re forced to search for life in similar situations. Habitable “goldilocks” zones are the target of planet-hunting missions like Kepler. The hope is that if we can find another Earth, then we can find another place that might have life.

But what if life doesn’t want to play ball? In his statement, Cockell warned that simply finding such a planet may not be enough: “On our planet, carbon leaches into most habitat space and provides energy for microorganisms to live. There are only a few vacant habitats that may persist for any length of time on Earth, but we cannot assume that this is the case on other planets.”

Is our planet a verdant oasis in an arid desert of a galaxy? Or, like in a desert, is there life we can’t readily see? In questioning how effective our current approach may be, Cockell highlights that there are currently three criteria that astrobiologists are really paying attention to.

First are biomarkers, signature gasses that we might recognize as having been created by living things. For example, on Earth, the oxygen, which makes up 21 percent of our atmosphere, is all created by living things. If there was no photosynthesis, Earth’s atmosphere would rapidly become devoid of oxygen.

Then there’s the criterion that alien life will widely colonize its home world. Again, on Earth, living things exist everywhere. “There are only a few vacant habitats that may persist for any length of time on Earth, but we cannot assume that this is the case on other planets,” Cockell said, pointing out that the pervasiveness of life on Earth leads us to make assumptions about life elsewhere.

Third, and most importantly: there will be enough alien life present to emit enough of those signature gasses that we would be able to detect them from Earth with our telescopes. Otherwise, we wouldn’t see them even if we were looking right at them.

Read more at Discovery News

Mar 21, 2013

'Sideline Quasars' Helped to Stifle Early Galaxy Formation

University of Colorado Boulder astronomers targeting one of the brightest quasars glowing in the universe some 11 billion years ago say "sideline quasars" likely teamed up with it to heat abundant helium gas billions of years ago, preventing small galaxy formation.

CU-Boulder Professor Michael Shull and Research Associate David Syphers used the Hubble Space Telescope to look at the quasar -- the brilliant core of an active galaxy that acted as a "lighthouse" for the observations -- to better understand the conditions of the early universe. The scientists studied gaseous material between the telescope and the quasar with a $70 million ultraviolet spectrograph on Hubble designed by a team from CU-Boulder's Center for Astrophysics and Space Astronomy.

During a time known as the "helium reionization era" some 11 billion years ago, blasts of ionizing radiation from black holes believed to be seated in the cores of quasars stripped electrons from primeval helium atoms, said Shull. The initial ionization that charged up the helium gas in the universe is thought to have occurred sometime shortly after the Big Bang.

"We think 'sideline quasars' located out of the telescope's view reionized intergalactic helium gas from different directions, preventing it from gravitationally collapsing and forming new generations of stars," he said. Shull likened the early universe to a hunk of Swiss cheese, where quasars cleared out zones of neutral helium gas in the intergalactic medium that were then "pierced" by UV observations from the space telescope.

The results of the new study also indicate the helium reionization era of the universe appears to have occurred later than thought, said Shull, a professor in CU-Boulder's astrophysical and planetary sciences department. "We initially thought the helium reionization era took place about 12 billion years ago," said Shull. "But now we think it more likely occurred in the 11 to 10 billion-year range, which was a surprise."

A paper on the subject by Shull and Syphers was published online this week in the Astrophysical Journal.

The Cosmic Origins Spectrograph used for the quasar observations aboard Hubble was designed to probe the evolution of galaxies, stars and intergalactic matter. The COS team is led by CU Professor James Green of CASA and was installed on Hubble by astronauts during its final servicing mission in 2009. COS was built in an industrial partnership between CU and Ball Aerospace & Technologies Corp. of Boulder.

"While there are likely hundreds of millions of quasars in the universe, there are only a handful you can use for a study like this," said Shull. Quasars are nuclei in the center of active galaxies that have "gone haywire" because of supermassive black holes that gorged themselves in the cores, he said. "For our purposes, they are just a really bright background light that allows us to see to the edge of the universe, like a headlight shining through fog."

The universe is thought to have begun with the Big Bang that triggered a fireball of searing plasma that expanded and then become cool neutral gas at about 380,000 years, bringing on the "dark ages" when there was no light from stars or galaxies, said Shull. The dark ages were followed by a period of hydrogen reionization, then the formation of the first galaxies beginning about 13.5 billion years ago. The first galaxies era was followed by the rise of quasars some 2 billion years later, which led to the helium reionization era, he said.

The radiation from the huge quasars heated the gas to 20,000 to 40,000 degrees Fahrenheit in intergalactic realms of the early universe, said Shull. "It is important to understand that if the helium gas is heated during the epoch of galaxy formation, it makes it harder for proto-galaxies to hang on to the bulk of their gas. In a sense, it's like intergalactic global warming."

The team is using COS to probe the "fossil record" of gases in the universe, including a structure known as the "cosmic web" believed to be made of long, narrow filaments of galaxies and intergalactic gas separated by enormous voids. Scientists theorize that a single cosmic web filament may stretch for hundreds of millions of light years, an eye-popping number considering that a single light-year is about 5.9 trillion miles.

COS breaks light into its individual components -- similar to the way raindrops break sunlight into the colors of the rainbow -- and reveals information about the temperature, density, velocity, distance and chemical composition of galaxies, stars and gas clouds.

For the study, Shull and Syphers used 4.5 hours of data from Hubble observations of the quasar, which has a catalog name of HS1700+6416. While some astronomers define quasars as feeding black holes, "We don't know if these objects feed once, or feed several times," Shull said. They are thought to survive only a few million years or perhaps a few hundred million years, a brief blink in time compared to the age of the universe, he said.

Read more at Science Daily

'Evolutionary Glitch' Possible Cause of Childhood Ear Infections

Researchers at King's College London have uncovered how the human ear is formed, giving clues as to why children are susceptible to infections such as glue ear.

The work was funded by the UK Medical Research Council and published today in the journal Science.

It is estimated that one in five children around the age of two will be affected by glue ear, a build-up of fluid in the middle ear chamber. This part of the ear contains three tiny bones that carry sound vibrations from the eardrum to the inner ear. When fluid builds up in the chamber, this prevents the three bones from moving freely so they cannot pass sound vibrations to the inner ear, causing temporary hearing loss. Until now, little was known about why some children appear much more prone than others to developing chronic ear problems, with repeated bouts of glue ear.

Carrying out studies in mice, scientists have discovered the cells that line the middle ear cavity originate from two different tissue types -- 'endoderm' and 'neural crest' cells. The part of the lining that originates from the endoderm is covered in a lawn of cilia (hairs) that help to clear debris from the ear, but the lining derived from neural crest cells do not have cilia. This makes that part of the middle ear less efficient at cleaning itself, leaving it susceptible to infection.

Interestingly, the process of the middle ear transforming into an air-filled space during development appears to be different in birds and reptiles, which have just one little ear bone. Mammals may have evolved this new mechanism for creating an air-filled space to house the additional bones. This indicates that the process of two distinct cell types to create the lining of the middle ear cavity may be linked to the evolution of the three tiny sound-conducting bones.

Dr Abigail Tucker from the Department of Craniofacial Development at King's College London's Dental Institute, said: "Our study has uncovered a new mechanism for how the middle ear develops, identifying a possible reason for why it is prone to infection. The process of neural crest cells making up part of the middle ear appears fundamentally flawed as these cells are not capable of clearing the ear effectively. While this process may have evolved in order to create space in the ear for the three little bones essential for hearing, the same process has left mammals prone to infection -- it's an evolutionary glitch.

Read more at Science Daily

'Lost' Tectonic Plate Found Under California

Ever have one of those days when you can’t find anything: your keys, your cell phone or that darned Farallon tectonic plate? I’m happy to report some progress on the plate. The Farallon plate, what’s left of it, is just fragments of oceanic crust off the West Coast. The lost part was pushed east and subducted under the North American plate, probably accompanied by a ultra-ultra-low frequency, multi-million-year-long munching sound that can’t even be heard by elephants.

Scientists are now reporting they have found a big chunk of the Farallon plate still stuck in the subduction digestion system, so to speak, some 100 to 200 kilometers under California. The researchers explain it all in far more appropriate and scientific terms in a paper in this week’s issue of Proceedings of the National Academy of Sciences.

But if you’d rather get the short version, here it is: They found, specifically, evidence that a seismological blob called the Isabella anomaly (“IA” in the map above) is a slab of the Farallon plate that got stuck to the underside of the North American plate instead of dropping off into the Earth’s mantle.

The anomaly itself is a large slab of relatively cool and dried out rock. Geologists know this because of the way seismic waves pass through it: slower waves usually means softer, hotter material while faster waves mean stiffer and cooler rocks.

The Isabella Anomaly has been known for a while. But by comparing it with another seismological blob under Baja California, which, for a bunch of reasons, is even more certainly a piece of the Farallon plate, the researchers, led by Donald Forsyth of Brown University and Tun Wang of the University of Alaska, reexamined the seismic data of the West Coast and were able to make an argument that the Isabella anomaly is more of the same. It is the same depth, treats seismic waves the same and, very significantly, the blob is in the right place.

“The geometry was the kicker,” Forsyth said in a Brown press release. “The way they line up just makes sense.”

Read more at Discovery News

Universe Older Than Thought, New Map Reveals

The universe is 100 million years older than thought, according to the best-ever map of the oldest light in space.

The adjustment brings the universe's age to 13.82 billion years, and means space and time are expanding slightly slower than scientists thought.

These discoveries come from a new all-sky map of ancient cosmic light by Europe's Planck mission, which has measured what's called the cosmic microwave background in greater detail than ever before.

"Astronomers worldwide have been on the edge of their seats waiting for this map," said Joan Centrella, Planck program scientist at NASA Headquarters in Washington, in a statement. NASA contributed technology for the Planck spacecraft, which is managed by the European Space Agency. "These measurements are profoundly important to many areas of science, as well as future space missions."

The cosmic microwave background (CMB) is light dating from just 380,000 years after the Big Bang. Before that time, the universe was so hot and dense that light couldn't travel through space without getting mired in a thick plasma of protons and electrons. When the universe finally cooled and expanded enough for atoms to form, light could travel freely for the first time, and this light has been flying through the universe ever since.

Astronomers first discovered the CMB by accident in 1964, and have been studying it ever since because of the precious clues about the universe's beginnings embedded in it.

For example, though the CMB is spread throughout space, it isn't entirely uniform. It displays small variations in temperature at different spots that scientists think correspond with regions of the early universe that were slightly more or less dense with energy. These fluctuations are thought to have been the seeds that eventually caused matter to clump in the denser spots and over time evolve into galaxies and stars and planets.

The new map shows these variations in more detail than ever before, and could help scientists distinguish between different theories of how the universe began. In general, Planck's measurements are consistent with a theory called the Standard Model, which posits that the variations in the CMB were caused by tiny random quantum fluctuations. However, the new map shows tantalizing hints that physics beyond the Standard Model may be needed to fully explain the CMB.

In particular, the CMB variations don't match the Standard Model's predictions at large scales, though they do on small scales. Other odd discoveries, such as a cold spot that is much larger than expected in one area of the sky, add to this picture.

"The extraordinary quality of Planck's portrait of the infant universe allows us to peel back its layers to the very foundations, revealing that our blueprint of the cosmos is far from complete," said Jean-Jacques Dordain, director general of the European Space Agency.

The disagreements with the Standard Model are actually good news to physicists, who know they need more than this theory alone to explain the whole of the universe anyway. For instance, the Standard Model does not include any explanation for dark matter or dark energy, the two largest constituents of the universe that so far remain mysterious.

Read more at Discovery News

Mar 20, 2013

Globetrotting Giant Squid Are All One Species

Giant squid, which can grow to an astounding 43 feet long, have equally extraordinary DNA, a new study concludes.

The long-awaited report, published in the Proceedings of the Royal Society B, finds that there is “exceptionally low” genetic diversity among giant squid from around the world.

“These observations are consistent with the hypotheses that there is only one global species of giant squid, Architeuthis dux,” wrote Inger Winkelmann and colleagues, who suggested that the squid could have one of the largest known ranges of any species.

Little is known about giant squid, which can live some 3,300 feet below the surface. Mostly we know about them from fantasy adventure books, like “20,000 Leagues Under the Sea,” and images of them dead, with their long tentacles dangling far beyond the picture frame. Giant squid are rarely captured alive, with most found stranded on beaches or seen floating dead on the water’s surface. Unfortunately, some are also retrieved by fisheries as by-catch .

Winkelmann, from the University of Copenhagen’s Natural History Museum of Denmark, and colleagues studied the mitochondrial genome of tissue samples from 43 such giant squid. “Mitochondrial” refers to a type of DNA inherited only through the female line. The squid came from all over the world, including waters off of California, Florida, Spain, Japan and New Zealand.

Incredibly, all had the same basic mitochondrial genomes. If there is just one giant squid species, as the researchers suspect, then adults must travel huge distances. Younger squid might disperse via drifting.

Giant squid might also be more plentiful than previously thought. But the lack of genetic diversity could make this species more vulnerable to human impact. Back in the day, fishermen rarely encountered the deep-dwelling squid. Now, with modern trawling equipment and huge fishing operations, the squid are more likely to become by-catch.

Read more at Discovery News

Why Do Even Microbes Commit Suicide?

A study on suicidal E. coli sheds light on why organisms throughout the animal kingdom, big and small, sometimes decide to do themselves in.

The good news is that suicide appears to be comparatively rare in larger animals, but more common among microscopic life forms, such as microbes, according to the study, published in the latest Proceedings of the Royal Society B.

Natural selection -- the process by which organisms that adapt to their environment tend to survive and produce more offspring -- favors suicide when the death guarantees the survival of relatives and the individual is less likely to reproduce in future.

An example of this, according to study co-author Rolf Kümmerli, is when "a parent saves his children out of a burning house. This is beneficial because the rescued relatives share many of the genes with the suicidal helper." Many people are driven to save their kids and close loved ones, no matter what.

Other forms of suicide among humans, such as bombers on a kamikaze mission, likely have nothing to do with natural selection, and instead reflect the by-product of something else. In the case of the bomber, that could be the individual's environment and life’s experiences. Depression or other forms of mental illness, however, could be inherited.

Kümmerli, a professor in the department of Microbial Evolutionary Ecology at the University of Zürich, and colleagues Dominik Refardt and Tobias Bergmiller investigated the suicidal behavior of E. coli. Some cells of this common bacteria will kill themselves in the presence of bacteria-killing parasitic viruses.

Kümmerli explained to Discovery News that when a protein of an E. coli cell senses viral attack, it becomes activated and, with other proteins, triggers drainage of membrane holes of the bacterial cell. It’s as though the cell biochemically stabs itself.

"Consequently, vital cell liquid and components pour out into the environment, which leads to cell death," he said. "The dead cell is presumably like an empty perforated sack."

Even among lowly microbes, such behavior would seem to go against survival and procreation mechanisms. Behaviors that benefit others, at the expense of the individual, however, can emerge when multiple relatives are saved. They can also emerge to benefit unrelated others when the cost of suicide is low.

In the case of E. coli cells, they would likely die from the viral attack anyway, and their death prevents parasite transmission to nearby other E. coli cells.

Suicide is also well documented in social insects that tend to live in large populations, such as ants and bees. Some ants will even explode themselves to prevent intruders from attacking their relatives.

Suicides among non-human mammals and other larger animals are mostly anecdotal, but they do tend to once again apply to social species, such as dogs and dolphins. Dolphin trainer Ric O'Barry, for example, claimed that he watched the famous TV star dolphin, Flipper, take her own life out of sheer depression due to confinement in captivity. O'Barry later became an animal activist.

Gaining a better understanding of the drivers behind suicide could lead to life-saving benefits. Researchers in future might be able to coax harmful bacteria, viruses and other microbial organisms to kill themselves, potentially saving human and other animal lives.

Read more at Discovery News

Ancient Giant Trees Found Petrified in Thailand

Fossil trees that approached the heights of today’s tallest redwoods have been found in northern Thailand. The longest petrified log measures 72.2 meters (237 feet), which suggest the original tree towered to more than 100 meters (330 feet) in a wet tropical forest some 800,000 years ago.

The trees appear to have been closely related to a species alive today called Koompassia elegans, which belongs to the same family as beans, peas and black locust trees, explained lead author of the study, Marc Philippe of France’s University of Lyon. That is to say, the ancient trees are not closely related to today’s tallest trees, which are the Eucalyptus (gum trees) of Australia and Sequoia (redwoods) of California. Both of those living trees can reach about 130 meters (425 feet) in height.

Interestingly, there are no trees living today in Thailand that approach the size of the ancients.

“Highest trees nowadays in Thailand are almost 60 meters (200 feet),” wrote Philippe in response to my email query about his new paper coming out in the April issue of the journal Quaternary Science Reviews. ”To my knowledge the highest tree yet recorded in Thailand is a Krabak tree, belonging to the Dipterocarpaceae (‘tropical oaks’), 58 meters (190 feet) tall.”

The sediments in which the fossil trees were found suggest that they lived in a wet forest at the edge of a lowland plain. Today the fossil trees are at an elevation of 170 meters (550 feet) above sea level and the climate flips between wet and dry seasons — what’s called monsoonal. Philippe says it’s possible there has been some uplift of the region since the trees fell.

Just how these buried trees were found is an interesting story in itself. A small section of a large petrified log was found ten years ago by a villager in a reserve forest at Ban Tak District, Tak Province. The discovery was reported to officials of the National Park, Wildlife and Plant Conservation Department and so an official came out to examine the log and surveyed the surrounding area. The log was then excavated to a length of 21 meters (70 feet) without reaching the end. Ground penetrating radar was brought in and found that 30 meters (100 feet) of trunk were still unexposed. In 2005, funds were found to excavate the whole trunk. At present, seven of nine discovered petrified trunks have been excavated, mostly in 2005.

“The result was the appearance of what is considered the world’s longest piece of petrified wood, with a length of 72.22 meters” (236.9 feet), the researchers report. “In 2006, the name of the park was changed to the Petrified Forest Park because of the fascinating discoveries.”

Read more at Discovery News

Voyager 1 Hits New Solar System Exit Zone

NASA's Voyager 1 spacecraft has reached a new and possibly last leg in a 35-year journey that is taking it out of the solar system, scientists said Wednesday.

The evidence comes from a sudden change in radiation levels measured by Voyager 1 on Aug. 25, 2012. On that day, particles caused by cosmic rays trapped in the envelope of space under the sun's influence, the heliosphere, virtually vanished. At the same time, measurements of galactic cosmic rays from outside the solar system spiked to levels not seen since Voyager's launch.

"Within just a few days, the heliospheric intensity of trapped radiation decreased, and the cosmic
 ray intensity went up as you would expect if it exited the heliosphere," astronomer Bill Webber,
 a professor emeritus at New Mexico State University in Las Cruces, said in a statement.

Still to be determined is if Voyager 1 is in interstellar space or a new, previously unknown region between the solar system and interstellar space.

"It's outside the normal heliosphere, I would say that," Webber said. "Everything we're measuring is different and exciting."

In December, Voyager 1 reached what scientists called a "magnetic highway," where magnetic field lines from the sun connect with magnetic field lines from interstellar space. The phenomenon causes highly energetic particles from distant supernova explosions and other cosmic events to zoom inside the solar system, while less-energetic solar particles exit.

Scientists said they don't know how long it will take for Voyager 1 to cross the boundary, but they believed it was the last leg in a complex zone lying between the heliosphere and interstellar space.

"Our best guess is it's likely just a few months to a couple years away," Stone told Discovery News in December.

Stone was traveling and could not be reached for comment on Wednesday.

Voyager 1 hit the outer sphere of the solar system in 2004 and passed into the heliosheath, where the supersonic stream of particles from the sun -- the so-called "solar wind" -- slowed down and became turbulent.

That phase of the journey lasted for 5.5 years. Then the solar wind stopped moving and the magnetic field strengthened.

Based on an instrument that measures charged particles, Voyager entered the magnetic highway on July 28, 2012. The region was in flux for about a month and stabilized on Aug. 25.

Each time Voyager re-entered the highway, the magnetic field strengthened, but its direction remained unchanged. Scientists believe the direction of the magnetic field lines will shift when the probe finally enters interstellar space.

Stone said that another clue that Voyager has reached interstellar space could be the detection of low-energy cosmic rays and a dramatic tapering of the number of solar particles.

In a statement, Stone said he didn’t believe Voyager 1 had yet passed into interstellar space because the probe has not yet detected a change in the direction of the magnetic field.

"This is the last critical indicator of reaching interstellar space and that change of direction has not yet been observed,” Stone said.

Voyager 1 and a sister spacecraft, Voyager 2, were launched 16 days apart in 1977 for the first flybys of Jupiter, Saturn, Uranus and Neptune.

Read more at Discovery News

Mar 19, 2013

Scientists Discover Reasons Behind Snakes' 'Shrinking Heads'

An international team of scientists led by Dr Kate Sanders from the University of Adelaide, and including Dr Mike Lee from the South Australian Museum, has uncovered how some sea snakes have developed 'shrunken heads' -- or smaller physical features than their related species.

Their research is published today in the journal Molecular Ecology.

A large head -- "all the better to eat you with" -- would seem to be indispensable to sea snakes, which typically have to swallow large spiny fish. However, there are some circumstances where it wouldn't be very useful: sea snakes that feed by probing their front ends into narrow, sand eel burrows have evolved comically small heads.

The team has shown normal-shaped sea snakes can evolve such "shrunken heads" very rapidly. This process can lead to speciation (one species splitting into two).

The small-headed populations are also much smaller in absolute size than their ancestors, and these shape and size differences mean they tend to avoid interbreeding with their large-headed ancestors.

Dr Lee says, "A team led by my colleague Dr Kate Sanders (University of Adelaide) has been investigating genetic differences across all sea snakes, and we noticed that the blue-banded sea snake (Hydrophis cyanocinctus) and the slender-necked sea snake (Hydrophis melanocephalus) were almost indistinguishable genetically, despite being drastically different in size and shape.

"The slender-necked sea snake is half the size, and has a much smaller head, than the blue-banded sea snake.

"This suggested they separated very recently from a common ancestral species and had rapidly evolved their different appearances.

"One way this could have happened is if the ancestral species was large-headed, and a population rapidly evolved small heads to probe eel burrows -- and subsequently stopped interbreeding with the large-headed forms."

Read more at Science Daily

Microbes Thrive in Deepest Spot on Earth

The deepest oceanic trench on Earth is home to a surprisingly active community of bacteria, suggesting other trenches may be hotspots of microbial life, researchers say.

Life in the deep ocean often relies on organic matter snowing down from above. As these particles waft down, their nutrients get degraded by microbes attached to them, so only 1 to 2 percent of the organic matter produced in surface waters is expected to make it to the average ocean depth of about 12,150 feet (3,700 meters). Just how much makes it to the very deepest parts is unknown.

To learn more about life in the dirt at the ocean's depths, scientists used a submersible lander to analyze mud from the surface of Challenger Deep, the deepest spot of the Mariana Trench at the bottom of the central west Pacific Ocean. This 36,000-foot-deep (11,000 m) trench is the deepest known point on Earth's surface.

Natural trap

The researchers analyzed the levels of oxygen consumption within the sediments, which revealed how active the deep-sea microbes were. They discovered unexpectedly high rates of oxygen consumption from the Mariana seafloor, indicating a microbial community twice as active as that of a nearby 19,700-foot (6,000 m) site about 35 miles (60 kilometers) to the south.

"In the most remote, inhospitable places, you can actually have higher activity than their surroundings," researcher Ronnie Glud, a biogeochemist at the Southern Danish University in Odense, Denmark, told OurAmazingPlanet.

Sediments from Challenger Deep also had significantly higher levels of microbes and organic compounds than the nearby, more elevated site. The investigators suggest the Mariana Trench acts as a natural trap for sediments from up high. Similar effects are seen in other submarine canyons.

"It acts as a trap just because it's a big hole. If you have a hole in a garden, it just fills up because things blowing over it tend to fall in, and the same is true with the seafloor," Glud said. The trench is also located in a subduction zone where one of the tectonic plates making up the surface of the Earth is diving under another, "and these areas are very unstable, and frequently see earthquakes that can trigger mudslides that transport material into the trench," he added.

Microbes, microbes everywhere

Another team of scientists recently discovered communities of microbes thriving in the oceanic crust. That research looked at rocks up to about 1,150 to 1,900 feet (350 to 580 m) below the seafloor under about 8,500 feet (2,600 m) of water off the coast of the northwestern United States. These microbes apparently live off energy from chemical reactions between water and rock instead of nutrients snowing from above.

"You can find microbes everywhere — they're extremely adaptable to conditions, and survive wherever they are," Glud said.

Read more at Discovery News

Earthquakes Turn Water Into Gold

Earthquakes have the Midas touch, a new study claims.

Water in faults vaporizes during an earthquake, depositing gold, according to a model published in the March 17 issue of the journal Nature Geoscience. The model provides a quantitative mechanism for the link between gold and quartz seen in many of the world's gold deposits, said Dion Weatherley, a geophysicist at the University of Queensland in Australia and lead author of the study.

When an earthquake strikes, it moves along a rupture in the ground — a fracture called a fault. Big faults can have many small fractures along their length, connected by jogs that appear as rectangular voids. Water often lubricates faults, filling in fractures and jogs.

About 6 miles (10 kilometers) below the surface, under incredible temperatures and pressures, the water carries high concentrations of carbon dioxide, silica and economically attractive elements like gold.

Shake, rattle and gold

During an earthquake, the fault jog suddenly opens wider. It's like pulling the lid off a pressure cooker: The water inside the void instantly vaporizes, flashing to steam and forcing silica, which forms the mineral quartz, and gold out of the fluids and onto nearby surfaces, suggest Weatherley and co-author Richard Henley, of the Australian National University in Canberra.

While scientists have long suspected that sudden pressure drops could account for the link between giant gold deposits and ancient faults, the study takes this idea to the extreme, said Jamie Wilkinson, a geochemist at Imperial College London in the United Kingdom, who was not involved in the study.

"To me, it seems pretty plausible. It's something that people would probably want to model either experimentally or numerically in a bit more detail to see if it would actually work," Wilkinson told OurAmazingPlanet.

Previously, scientists suspected fluids would effervesce, bubbling like an opened soda bottle, during earthquakes or other pressure changes. This would line underground pockets with gold. Others suggested minerals would simply accumulate slowly over time.

Weatherley said the amount of gold left behind after an earthquake is tiny, because underground fluids carry at most only one part per million of the precious element. But an earthquake zone like New Zealand's Alpine Fault, one of the world's fastest, could build a mineable deposit in 100,000 years, he said.

Surprisingly, the quartz doesn't even have time to crystallize, the study indicates. Instead, the mineral comes out of the fluid in the form of nanoparticles, perhaps even making a gel-like substance on the fracture walls. The quartz nanoparticles then crystallize over time.

Even earthquakes smaller than magnitude 4.0, which may rattle nerves but rarely cause damage, can trigger flash vaporization, the study finds.

"Given that small-magnitude earthquakes are exceptionally frequent in fault systems, this process may be the primary driver for the formation of economic gold deposits," Weatherley told OurAmazingPlanet.

The hills have gold

Quartz-linked gold has sourced some famous deposits, such as the placer gold that sparked the 19th-century California and Klondike gold rushes. Both deposits had eroded from quartz veins upstream. Placer gold consists of particles, flakes and nuggets mixed in with sand and gravel in stream and river beds. Prospectors traced the gravels back to their sources, where hard-rock mining continues today.

But earthquakes aren't the only cataclysmic source of gold. Volcanoes and their underground plumbing are just as prolific, if not more so, at producing the precious metal. While Weatherley and Henley suggest that a similar process could take place under volcanoes, Wilkinson, who studies volcano-linked gold, said that's not the case.

Read more at Discovery News

Inbreeding Common in Early Humans

The evidence comes from fragments of an approximately 100,000-year-old human skull unearthed at a site called Xujiayao, located in the Nihewan Basin of northern China. The skull's owner appears to have had a now-rare congenital deformity that probably arose through inbreeding, researchers report in the journal PLOS ONE.

The fossil, now dubbed Xujiayao 11, is just one of many examples of ancient human remains that display rare or unknown congenital abnormalities, according to the researchers. "These populations were probably relatively isolated, very small and, as a consequence, fairly inbred," study leader Erik Trinkhaus, an anthropologist at Washington University in St. Louis, told LiveScience.

The human skull fossil has a hole at its top, a disorder known as an "enlarged parietal foramen," which matches a modern human condition of the same name caused by a rare genetic mutation. The genetic abnormalities obstruct bone formation by preventing small holes in the prenatal braincase from closing, a process that normally occurs within the first five months of the fetus' development. Today, these mutations are rare, occurring in only about one of every 25,000 human births.

The skull appears to be from an individual who lived into middle age, indicating the abnormality was not lethal. The skull deformity can sometimes lead to cognitive deficits, but the age of the individual suggests any deficits probably would have been minor, Trinkhaus said.

The skulls of humans from the Pleistocene epoch (roughly 2.6 million to 12,000 years ago) show an unusually high occurrence of genetic abnormalities like this skull-hole deformity, the researchers found. Scientists have seen these abnormalities in fossils from the time of early Homo erectus to the end of the early Stone Age.

Such a high frequency of genetic abnormalities in the fossil record "reinforces the idea that during much of this period of human evolution, human populations were very small" and, consequently, likely inbred, Trinkhaus said.

Read more at Discovery News

Mar 18, 2013

Antarctica's First Whale Skeleton Found With Nine New Deep-Sea Species

Marine biologists have, for the first time, found a whale skeleton on the ocean floor near Antarctica, giving new insights into life in the sea depths. The discovery was made almost a mile below the surface in an undersea crater and includes the find of at least nine new species of deep-sea organisms thriving on the bones.

The research, involving the University of Southampton, Natural History Museum, British Antarctic Survey, National Oceanography Centre (NOC) and Oxford University, is published today in Deep-Sea Research II: Topical Studies in Oceanography.

"The planet's largest animals are also a part of the ecology of the very deep ocean, providing a rich habitat of food and shelter for deep sea animals for many years after their death," says Diva Amon, lead author of the paper based at University of Southampton Ocean and Earth Science (which is based at NOC) and the Natural History Museum. "Examining the remains of this southern Minke whale gives insight into how nutrients are recycled in the ocean, which may be a globally important process in our oceans."

Worldwide, only six natural whale skeletons have ever been found on the seafloor. Scientists have previously studied whale carcasses, known as a 'whale fall', by sinking bones and whole carcasses. Despite large populations of whales in the Antarctic, whale falls have not been studied in this region until now.

"At the moment, the only way to find a whale fall is to navigate right over one with an underwater vehicle," says co-author Dr Jon Copley of University of Southampton Ocean and Earth Science. Exploring an undersea crater near the South Sandwich Islands gave scientists just that chance encounter. "We were just finishing a dive with the UK's remotely operated vehicle, Isis, when we glimpsed a row of pale-coloured blocks in the distance, which turned out to be whale vertebrae on the seabed," continues Dr Copley.

When a whale dies and sinks to the ocean floor, scavengers quickly strip its flesh. Over time, other organisms then colonise the skeleton and gradually use up its remaining nutrients. Bacteria break down the fats stored in whale bones, for example, and in turn provide food for other marine life. Other animals commonly known as zombie worms can also digest whale bone.

"One of the great remaining mysteries of deep ocean biology is how these tiny invertebrates can spread between the isolated habitats these whale carcasses provide on the seafloor," says co-author Dr Adrian Glover at the Natural History Museum. 'Our discovery fills important gaps in this knowledge.'

Read more at Science Daily

Oxygen-Poor 'Boring' Ocean Challenged Evolution of Early Life

A research team led by biogeochemists at the University of California, Riverside has filled in a billion-year gap in our understanding of conditions in the early ocean during a critical time in the history of life on Earth.

It is now well accepted that appreciable oxygen first accumulated in the atmosphere about 2.4 to 2.3 billion years ago. It is equally well accepted that the build-up of oxygen in the ocean may have lagged the atmospheric increase by well over a billion years, but the details of those conditions have long been elusive because of the patchiness of the ancient rock record.

The period 1.8 to 0.8 billion years ago is of particular interest because it is the essential first chapter in the history of eukaryotes, which are single-celled and multicellular organisms with more complex cellular structures compared to prokaryotes such as bacteria. Their rise was a milestone in the history of life, including that of animals, which first appear around 0.6 to 0.7 billion years ago.

The most interesting thing about the billion-year interval is that despite the rise of oxygen and eukaryotes, the first steps forward were small and remarkably unchanging over a very long period, with oxygen likely remaining low in the atmosphere and ocean and with marine life dominated by bacteria rather than diverse and large populations of more complex eukaryotes. In fact, chemical and biological conditions in this middle age of Earth history were sufficiently static to earn this interval an unflattering nickname -- 'the boring billion.'

But lest it be thought that such a 'boring' interval is uninteresting, the extraordinary circumstances required to maintain such biological and chemical stasis for a billion years are worthy of close study, which is what motivated the UC Riverside-led team.

By compiling data for metals with very specific and well-known chemical responses to oxygen conditions in the ocean, emphasizing marine sediments from this critical time interval from around the world, the researchers revealed an ancient ocean that was oxygen-free (anoxic) and iron-rich in the deepest waters and hydrogen sulfide-containing over limited regions on the ocean margins.

"Oxygen, by contrast, was limited, perhaps at very low levels, to the surface layers of the ocean," said Christopher T. Reinhard, the first author of the research paper and a former UC Riverside graduate student. "What's most unique about our study, however, is that by applying numerical techniques to the data, we were able to place estimates, for the first time, on the full global extent of these conditions. Our results suggest that most of the deep ocean was likely anoxic, compared to something much less than 1 percent today."

Study results appear online this week in the Proceedings of the National Academy of Sciences.

"A new modeling approach we took allowed us to build on our past work, which was mostly limited to defining very localized conditions in the ancient ocean," Reinhard said. "The particular strength of the method lies in its ability to define chemical conditions on the seafloor that have long since been lost to plate tectonic recycling."

Reinhard, now a postdoctoral fellow at Caltech and soon to be an assistant professor at Georgia Institute of Technology, explained that chromium and molybdenum enrichments in ancient organic-rich sedimentary rocks, the focus of the study, actually track the amount of the metals present in ancient seawater. Critically, those concentrations are fingerprints of global ocean chemistry.

Beyond the utility of chromium and molybdenum for tracking oxygen levels in the early ocean, molybdenum is also a bioessential element critical in the biological cycling of nitrogen, a major nutrient in the ocean.

Read more at Science Daily

Frog that Gave Birth Through Its Mouth Near Revival

Scientists have revived the genome of an extinct Australian frog that gave birth through its mouth.

The scientists, working as part of the aptly named Lazarus Project, used sophisticated cloning technology to implant a “dead” cell nucleus into a fresh egg from another frog species.

“We are watching Lazarus arise from the dead, step by exciting step,” leader of the Lazarus Project team, Mike Archer of the University of New South Wales, said in a University of New South Wales press release.

“We’ve reactivated dead cells into living ones and revived the extinct frog’s genome in the process. Now we have fresh cryo-preserved cells of the extinct frog to use in future cloning experiments.”

Before they went extinct in 1983, females of the gastric-brooding frog, Rheobatrachus silus, swallowed their eggs, brooded their young in their stomachs, and then gave birth through their mouths.

The scientific team managed to recover cell nuclei from tissues of the frog that were collected in the 1970s. They kept them for 40 years in a conventional deep freezer.

According to the release:

In repeated experiments over five years, the researchers used a laboratory technique known as somatic cell nuclear transfer. They took fresh donor eggs from the distantly related great barred frog, Mixophyes fasciolatus, inactivated the egg nuclei and replaced them with dead nuclei from the extinct frog. Some of the eggs spontaneously began to divide and grow to early embryo stage – a tiny ball of many living cells. Although none of the embryos survived beyond a few days, genetic tests confirmed that the dividing cells contain the genetic material from the extinct frog.

While the extinct frog hasn’t risen from the dead yet, it’s genome now has, lending hope that this species will one day live again.

“We’re increasingly confident that the hurdles ahead are technological and not biological and that we will succeed,” Archer said. “Importantly, we’ve demonstrated already the great promise this technology has as a conservation tool when hundreds of the world’s amphibian species are in catastrophic decline.”

He recently spoke publicly about the Lazarus Project and also about his ongoing interest in cloning the extinct Australian thylacine, or Tasmanian tiger, at the TEDx DeExtinction event in Washington, D.C. Researchers from around the world are gathered there to discuss progress and plans to resurrect other extinct animals and plants.

Possible candidate species include the woolly mammoth, dodo, Cuban red macaw and New Zealand’s giant moa.

Read more at Discovery News

Rembrandt Self-portrait Confirmed in British Home

A painting hanging in a British stately home has been confirmed as a self-portrait by Rembrandt worth tens of millions of dollars, the National Trust heritage body announced on Friday.

The picture, which has been at Buckland Abbey in Devon, southwest England, since it was donated to the trust in 2010, was thought for decades to be a portrait by one of the Dutch Master's pupils.

But the world's leading Rembrandt expert has now re-attributed it to the 17th-century master himself.

It has been given a new value of £20 million -- though the National Trust said it can never be sold as the organization holds items on behalf of the nation forever.

"These latest investigations are incredibly exciting and important," said David Taylor, the trust's curator of paintings and sculpture.

"Conservation work and technical analysis being undertaken over the winter will give us further confirmation regarding the picture's authorship."

The self-portrait, dated 1635, shows the artist aged 29 wearing a cap with large white ostrich feathers.

The painting was donated to the National Trust by the widow of a wealthy property developer in her estate.

The painting will hang at the 700-year-old abbey -- which was formerly the home of 16th-century explorer Francis Drake -- for another eight months before being sent for cleaning and further examination.

When it first arrived at the abbey it was kept in storage for 18 months as there was nowhere to hang it, but it now becomes one of the National Trust's most important paintings.

Read more at Discovery News

Mar 17, 2013

Highly Effective Communities of Bacteria in the World's Deepest Oceanic Trench

An international research team announces the first scientific results from one of the most inaccessible places on Earth: the bottom of the Mariana Trench located nearly 11 kilometers below sea level in the western Pacific, which makes it the deepest site on Earth.

Their analyses document that a highly active bacteria community exists in the sediment of the trench -- even though the environment is under extreme pressure almost 1,100 times higher than at sea level.

In fact, the trench sediments house almost 10 times more bacteria than in the sediments of the surrounding abyssal plain at much shallower water depth of 5-6 km water.

Deep sea trenches are hot spots

Deep sea trenches act as hot spots for microbial activity because they receive an unusually high flux of organic matter, made up of dead animals, algae and other microbes, sourced from the surrounding much shallower sea-bottom. It is likely that some of this material becomes dislodged from the shallower depths during earthquakes, which are common in the area. So, even though deep sea trenches like the Mariana Trench only amount to about two percent of the World Ocean area, they have a relatively larger impact on marine carbon balance -- and thus on the global carbon cycle, says Professor Ronnie Glud from Nordic Center for Earth Evolution at the University of Southern Denmark.

Ronnie Glud and researchers from Germany (HGF-MPG Research Group on Deep-Sea Ecology and Technology of the Max Planck Institute in Bremen and Alfred Wegener Institute in Bremerhaven), Japan (Japan Agency for Marine-Earth Science and Technology), Scotland (Scottish Association for Marine Science) and Denmark (University of Copenhagen), explore the deepest parts of the oceans, and the team's first results from these extreme environments are today published in the journal Nature Geoscience.

Diving robot

One of the team's methods was to measure the distribution of oxygen into these trench sediments as this can be related to the activity of microbes in the sediments. It is technically and logistically challenging to perform such measurements at great depths, but it is necessary in order to get accurate data on rates of bacterial activity. "If we retrieve samples from the seabed to investigate them in the laboratory, many of the microorganisms that have adapted to life at these extreme conditions will die, due to the changes in temperature and pressure. Therefore, we have developed instruments that can autonomously perform preprogrammed measuring routines directly on the seabed at the extreme pressure of the Marianas Trench," says Ronnie Glud. The research team has, together with different companies, designed the underwater robot which stands almost 4 m tall and weighs 600 kg. Among other things, the robot is equipped with ultrathin sensors that are gently inserted into the seabed to measure the distribution of oxygen at a high spatial resolution.

"We have also made videos from the bottom of the Mariana Trench, and they confirm that there are very few large animals at these depths. Rather, we find a world dominated by microbes that are adapted to function effectively at conditions highly inhospitable to most higher organisms," says Ronnie Glud.

The remaining "white spots"

The expedition of the Mariana Trench took place in 2010. Since then, the research team has sent their underwater robot to the bottom of the Japan Trench which is approximately 9 km deep, and later this year they are planning a dive in the world's second deepest trench, the 10.8 kilometers deep Kermadec-Tonga Trench near Fiji in the Pacific.

Read more at Science Daily

Will De-Extinction Become Reality?

Biologists briefly brought the extinct Pyrenean ibex back to life in 2003 by creating a clone from a frozen tissue sample harvested before the goat's entire population vanished in 2000. The clone survived just seven minutes after birth, but it gave scientists hope that "de-extinction," once a pipedream, could become a reality.

Ten years later, a group of researchers and conservationists gathered in Washington, D.C., Friday (March 15) for a forum called TEDxDeExtinction, hosted by the National Geographic Society, to talk about how to revive extinct animals, from the Tasmanian tiger and the saber-toothed tiger to the woolly mammoth and the North American passenger pigeon.

Though scientists don't expect a real-life "Jurassic Park" will ever be on the horizon, a species that died a few tens of thousands of years ago could be resurrected as long as it has enough intact ancient DNA.

Some have their hopes set on the woolly mammoth, a relative of modern elephants that went extinct 3,000 to 10,000 years ago and left behind some extraordinarily well preserved carcasses in Siberian permafrost. Scientists in Russia and South Korea have embarked on an ambitious project to try to create a living specimen using the DNA-storing nucleus of a mammoth cell and an Asian elephant egg — a challenging prospect, as no one has ever been able to harvest eggs from an elephant.

But DNA from extinct species doesn't need to be preserved in Arctic conditions to be useful to scientists — researchers have been able to start putting together the genomes of extinct species from museum specimens that have been sitting on shelves for a century. If de-extinction research has done anything for science, it's forced researchers to look at the quality of the DNA in dead animals, said science journalist Carl Zimmer, whose article on de-extinction featured on the cover of the April issue of National Geographic magazine.

"It's not that good but you can come up with techniques to retrieve it," Zimmer told LiveScience.

For instance, a team that includes Harvard genetics expert George Church is trying to bring back the passenger pigeon — a bird that once filled eastern North America's skies. They have been able to piece together roughly 1 billion letters (Each of four nucleotides that make up DNA has a letter designation) in the bird's genome based on DNA from a 100-year-old taxidermied museum specimen. They hope to incorporate those genes responsible for certain traits into the genome of a common rock pigeon to bring back the passenger pigeon, or at least create something that looks like it.

A few years ago, another group of researchers isolated DNA from a 100-year-old specimen of a young thylacine, also known as Tasmanian tiger. The pup had been preserved in alcohol at Museum Victoria in Melbourne. Its genetic material was inserted into mouse embryos, which proved functional in live mice.

Should we?

Now that de-extinction looms as a possibility, it presents some thorny questions: Should we bring back these species? And what would we do them?

Stuart Pimm of Duke University argued in an opinion piece in National Geographic that these efforts would be a "colossal waste" if scientists don't know where to put revived species that had been driven off the planet because their habitats became unsafe.

"A resurrected Pyrenean ibex will need a safe home," Pimm wrote. "Those of us who attempt to reintroduce zoo-bred species that have gone extinct in the wild have one question at the top of our list: Where do we put them? Hunters ate this wild goat to extinction. Reintroduce a resurrected ibex to the area where it belongs and it will become the most expensive cabrito ever eaten."

Pimm also worries that de-extinction could create a false impression that science can save endangered species, turning the focus away from conservation. But others argue that bringing back iconic, charismatic creatures could stir support for species preservation.

"Some people feel that watching scientists bring back the great auk and putting it back on a breeding colony would be very inspiring," Zimmer told LiveScience. The great auk was the Northern Hemisphere's version of the penguin. The large flightless birds went extinct in the mid-19th century.

Other species disappeared before scientists had a chance to study their remarkable biological abilities — like the gastric brooding frog, which vanished from Australia in the mid-1980s, likely due to timber harvesting and the chytrid fungus.

"This was not just any frog," Mike Archer, a paleontologist at the University of New South Wales, said during his talk at TEDxDeExtinction, which was broadcast via livestream. These frogs had a unique mode of reproduction: The female swallowed fertilized eggs, turned its stomach into a uterus and gave birth to froglets through the mouth.

Read more at Discovery News