Fiery Volcano Offers Geologic Glimpse Into Land That Time Forgot

4:06:53 AM, Thursday, October 20, 2011

"The first scientists to witness exploding rock and molten lava from a deep sea volcano, seen during a 2009 expedition, report that the eruption was near a tear in Earth's crust that is mimicking the birth of a subduction zone.

Scientists on the expedition collected boninite, a rare, chemically distinct lava that accompanies the formation of Earth's subduction zones.

Nobody has ever collected fresh boninite and scientists never had the opportunity to monitor its eruption before, said Joseph Resing, University of Washington oceanographer and lead author of an online article on the findings in Nature Geoscience. Earth's current subduction zones are continually evolving but most formed 5 million to 200 million years ago. Scientists have only been able to study boninite collected from long-dead, relic volcanos millions of years old.

Resing was chief scientist on the expedition, funded by the National Oceanic and Atmospheric Administration and the National Science Foundation, that pinpointed the location of the West Mata volcano, erupting 4,000 feet (1,200 meters) below the surface in the Southwest Pacific Ocean.

"Everything about the eruption itself -- how fast, how intense, the ratio of lava to explosive fragments, the amount and composition of gas released -- is new to us," said co-author Kenneth Rubin, University of Hawaii geologist. "Plus, having a young, fresh occurrence of this very rare rock type to study gives us the opportunity to examine subtle chemical and mineralogical variations in a pristine specimen."

At subduction zones the oceanic crust on one tectonic plate slides beneath another, producing abundant volcanism and contributing heat, gases and mineral-laden fluids to ocean waters. Scientists have long studied the impact of subduction zones on geological and geochemical cycles. To puzzle out how subduction zones form and evolve they study inactive contemporary marine volcanos that do not produce boninite and they collect and study boninite lavas collected on land and examine cores collected from the deep sea.

"West Mata lies above the subducting Pacific plate and is part of the rapidly expanding Lau Basin, which is bounded by Samoa, Tonga and Fiji," Resing said. "The large bend at the northern end of the Tonga trench produces a tear in the Pacific plate and creates unusual lavas that usually only form at very young subduction zones."

Conditions are right for boninite to form, there's lots of seawater released from subducting rock that mixes into relatively shallow mantle that has previously melted, causing the mantle to remelt at high temperatures. Boninite lavas are believed to be among the hottest from volcanos that erupt on Earth..."

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Detroit Police Impound Booty Lounge Strip Club on Wheels

3:36:12 AM, Thursday, October 20, 2011

"Tailgating is an important part of going to see a sports event in person, and in the city of Detroit, that pastime also includes something called the Booty Lounge. The Booty Lounge is a low-rent strip-club on wheels, and it has been a somewhat shady part of the game-day experience in Detroit since 2005.

Owners of the mobile strip club were likely hoping for a big payday thanks to a Lions appearance on the NFL's Monday Night Football, but instead, the bus was impounded by Detroit Police. Detroit's NBC affiliate reports that the bus was towed way because it was parked illegally, the driver didn't have a commercial license and the vehicle wasn't inspected by the Michigan Department of Transportation. The fuzz reportedly weren't targeting the rolling tribute, but the bus recently came under fire after a local TV station uncovered the goings-on inside the bus.

The Booty Lounge will reportedly be cleared to exit the impound once it provides proof of inspection, but we're getting the feeling that this tailgater is going to be sitting out a quite few more games."

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Dark Matter Mystery Deepens

1:06:31 AM, Thursday, October 20, 2011

"Like all galaxies, our Milky Way is home to a strange substance called dark matter. Dark matter is invisible, betraying its presence only through its gravitational pull. Without dark matter holding them together, our galaxy's speedy stars would fly off in all directions. The nature of dark matter is a mystery -- a mystery that a new study has only deepened.

"After completing this study, we know less about dark matter than we did before," said lead author Matt Walker, a Hubble Fellow at the Harvard-Smithsonian Center for Astrophysics.

The standard cosmological model describes a universe dominated by dark energy and dark matter. Most astronomers assume that dark matter consists of "cold" (i.e. slow-moving) exotic particles that clump together gravitationally. Over time these dark matter clumps grow and attract normal matter, forming the galaxies we see today.

Cosmologists use powerful computers to simulate this process. Their simulations show that dark matter should be densely packed in the centers of galaxies. Instead, new measurements of two dwarf galaxies show that they contain a smooth distribution of dark matter. This suggests that the standard cosmological model may be wrong.

"Our measurements contradict a basic prediction about the structure of cold dark matter in dwarf galaxies. Unless or until theorists can modify that prediction, cold dark matter is inconsistent with our observational data," Walker stated.Dwarf galaxies are composed of up to 99 percent dark matter and only one percent normal matter like stars. This disparity makes dwarf galaxies ideal targets for astronomers seeking to understand dark matter.

Walker and his co-author Jorge Peñarrubia (University of Cambridge, UK) analyzed the dark matter distribution in two Milky Way neighbors: the Fornax and Sculptor dwarf galaxies. These galaxies hold one million to 10 million stars, compared to about 400 billion in our galaxy. The team measured the locations, speeds and basic chemical compositions of 1500 to 2500 stars..."

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U.S. Drug Policy Would Be Imposed Globally By New House Bill

12:21:06 AM, Thursday, October 20, 2011

"The House Judiciary Committee passed a bill yesterday that would make it a federal crime for U.S. residents to discuss or plan activities on foreign soil that, if carried out in the U.S., would violate the Controlled Substances Act (CSA) -- even if the planned activities are legal in the countries where they're carried out. H.R. 313, the "Drug Trafficking Safe Harbor Elimination Act of 2011," is sponsored by Judiciary Committee Chairman Rep. Lamar Smith (R-Texas), and allows prosecutors to bring conspiracy charges against anyone who discusses, plans or advises someone else to engage in any activity that violates the CSA, the massive federal law that prohibits drugs like marijuana and strictly regulates prescription medication.

"Under this bill, if a young couple plans a wedding in Amsterdam, and as part of the wedding, they plan to buy the bridal party some marijuana, they would be subject to prosecution," said Bill Piper, director of national affairs for the Drug Policy Alliance, which advocates for reforming the country's drug laws. "The strange thing is that the purchase of and smoking the marijuana while you're there wouldn't be illegal. But this law would make planning the wedding from the U.S. a federal crime."

The law could also potentially affect academics and medical professionals. For example, a U.S. doctor who works with overseas doctors or government officials on needle exchange programs could be subject to criminal prosecution. A U.S. resident who advises someone in another country on how to grow marijuana or how to run a medical marijuana dispensary would also be in violation of the new law, even if medical marijuana is legal in the country where the recipient of the advice resides. If interpreted broadly enough, a prosecutor could possibly even charge doctors, academics and policymakers from contributing their expertise to additional experiments like the drug decriminalization project Portugal, which has successfully reduced drug crime, addiction and overdose deaths.

The Controlled Substances Act also regulates the distribution of prescription drugs, so something as simple as emailing a friend vacationing in Tijuana some suggestions on where to buy prescription medication over the counter could subject a U.S. resident to criminal prosecution. "It could even be something like advising them where to buy cold medicine overseas that they'd have to show I.D. to get here in the U.S.," Piper says.

Civil libertarian attorney and author Harvey Silverglate says the bill raises several concerns. "Just when you think you can't get any more cynical, a bill like this comes along. I mean, it just sounds like an abomination. First, there's no intuitive reason for an American to think that planning an activity that's perfectly legal in another country would have any effect on America," Silverglate says. "So we're getting further away from the common law tradition that laws should be intuitive, and should include a mens rea component. Second, this is just an act of shameless cultural and legal imperialism. It's just outrageous."

Conspiracy laws in general are problematic when applied to the drug war. They give prosecutors extraordinary discretion to charge minor players, such as girlfriends or young siblings, with the crimes committed by major drug distributors. They're also easier convictions to win, and can allow prosecutors to navigate around restrictions like statutes of limitations, so long as the old offense can be loosely linked to a newer one. The Smith bill would expand those powers. Under the Amsterdam wedding scenario, anyone who participated in the planning of the wedding with knowledge of the planned pot purchase would be guilty of conspiracy, even if their particular role was limited to buying flowers or booking the hotel.

The law is a reaction to a 2007 case in which the 11th Circuit U.S. Court of Appeals threw out the convictions of two men who planned the transfer of cocaine from a Colombian drug cartel to a Saudi prince for distribution in Europe. Though the men planned the transaction from Miami, the court found that because the cocaine never reached the U.S. and was never intended to reach the U.S., the men hadn't committed any crime against the United States..."

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NASA's Spitzer Detects Comet Storm in Nearby Solar System

12:13:22 AM, Thursday, October 20, 2011

"NASA's Spitzer Space Telescope has detected signs of icy bodies raining down in an alien solar system. The downpour resembles our own solar system several billion years ago during a period known as the "Late Heavy Bombardment," which may have brought water and other life-forming ingredients to Earth.

During this epoch, comets and other frosty objects that were flung from the outer solar system pummeled the inner planets. The barrage scarred our moon and produced large amounts of dust.

Now Spitzer has spotted a band of dust around a nearby bright star in the northern sky called Eta Corvi that strongly matches the contents of an obliterated giant comet. This dust is located close enough to Eta Corvi that Earth-like worlds could exist, suggesting a collision took place between a planet and one or more comets. The Eta Corvi system is approximately one billion years old, which researchers think is about the right age for such a hailstorm.

"We believe we have direct evidence for an ongoing Late Heavy Bombardment in the nearby star system Eta Corvi, occurring about the same time as in our solar system," said Carey Lisse, senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., and lead author of a paper detailing the findings. The findings will be published in the Astrophysical Journal. Lisse presented the results at the Signposts of Planets meeting at NASA's Goddard Space Flight Center in Greenbelt, Md., on Oct. 19.

Astronomers used Spitzer's infrared detectors to analyze the light coming from the dust around Eta Corvi. Certain chemical fingerprints were observed, including water ice, organics and rock, which indicate a giant comet source.

The light signature emitted by the dust around Eta Corvi also resembles the Almahata Sitta meteorite, which fell to Earth in fragments across Sudan in 2008. The similarities between the meteorite and the object obliterated in Eta Corvi imply a common birthplace in their respective solar systems.

A second, more massive ring of colder dust located at the far edge of the Eta Corvi system seems like the proper environment for a reservoir of cometary bodies. This bright ring, discovered in 2005, looms at about 150 times the distance from Eta Corvi as Earth is from the sun. Our solar system has a similar region, known as the Kuiper Belt, where icy and rocky leftovers from planet formation linger. The new Spitzer data suggest that the Almahata Sitta meteorite may have originated in our own Kuiper Belt..."

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Prehistoric Speedway: Super-Sized Muscle Made Twin-Horned Dinosaur a Speedster

2:37:29 AM, Wednesday, October 19, 2011

"A meat-eating dinosaur that terrorized its plant-eating neighbours in South America was a lot deadlier than first thought, a University of Alberta researcher has found.

Carnotaurus was a seven-metre-long predator with a huge tail muscle that U of A paleontology graduate student Scott Persons says made it one of the fastest running hunters of its time.

A close examination of the tail bones of Carnotaurus showed its caudofemoralis muscle had a tendon that attached to its upper leg bones. Flexing this muscle pulled the legs backwards and gave Carnotaurus more power and speed in every step.

In earlier research, Persons found a similar tail-muscle and leg-power combination in the iconic predator Tyrannosaurus rex. Up until Persons published that paper, many dinosaur researchers thought T. rex's huge tail might have simply served as a teeter-totter-like counterweight to its huge, heavy head.

Persons' examination of the tail of Carnotaurus showed that along its length were pairs of tall rib-like bones that interlocked with the next pair in line. Using 3-D computer models, Persons recreated the tail muscles of Carnotaurus. He found that the unusual tail ribs supported a huge caudofemoralis muscle. The interlocked bone structure along the dinosaur's tail did present one drawback: the tail was rigid, making it difficult for the hunter to make quick, fluid turns. Persons says that what Carnotaurus gave up in maneuverability, it made up for in straight ahead speed. For its size, Carnotaurus had the largest caudofemoralis muscle of any known animal, living or extinct.

Persons published these findings in PLoS ONE on Oct.14, with supervisor Philip Currie, a paleontology professor at the U of A."

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Frozen Puck Hovers Over Track Using “Quantum Levitation”

12:18:44 AM, Wednesday, October 19, 2011

"Researchers at the school of physics and astronomy at Tel Aviv University have created a track around which a semiconductor can float, thanks to the phenomenon of “quantum levitation“.

This levitation effect is explained by the Meissner effect, which describes how, when a material makes the transition from its normal to its superconducting state, it actively excludes magnetic fields from its interior, leaving only a thin layer on its surface.

When a material is in its superconducting state — which involves very low temperatures — it is strongly diamagnetic. This means that when a magnetic field is externally applied, it will create an equally opposing magnetic field, locking it in place.

A material called yttrium barium copper oxide can be turned into a superconductor by exposure to liquid nitrogen — which makes it one of the highest-temperature superconductors.

In the video it appears that a puck of yttrium barium copper oxide cooled by liquid nitrogen is repelling the magnets embedded on the handheld device. It also shows that the angle of the magnet can be locked in a magnetic field. Later in the video the puck can be seen to zoom round a circular track of magnets, in the same way that Maglev high-speed trains do."

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Frustration Inspires New Form of Graphene

1:45:45 AM, Monday, October 17, 2011

"They're the building block of graphite – ultra-thin sheets of carbon, just one atom thick, whose discovery was lauded in 2010 with a Nobel Prize in Physics.

The seemingly simple material is graphene, and many researchers believe it has great potential for many applications, from electronic devices to high-performance composite materials.

Graphene is extremely strong, an excellent conductor, and with no internal structure at all, it offers an abundance of surface area – much like a sheet of paper.

When it comes to producing and utilizing graphene on a large scale, however, researchers have come upon a major problem: the material's tendency to aggregate. Like paper, graphene sheets easily stack into piles, thus greatly reducing their surface area and making them unprocessable.

Researchers at Northwestern University have now developed a new form of graphene that does not stack. The new material – inspired by a trash can full of crumpled-up papers – is made by crumpling the graphene sheets into balls.

A paper describing the findings, "Compression and Aggregation-resistant Particles of Crumpled Soft Sheets," was published October 13 in the journal ACS Nano.

Graphene-based materials are very easily aggregated due to the strong interaction between the sheets, called "Van der Waals attraction." Therefore, common steps in materials processing, such as heating, solvent washing, compression, and mixing with other materials, can greatly affect how the sheets are stacked. When the paper-like sheets band together – picture a deck of cards – their surface area is lost; with just a fraction of its original surface area available, the material becomes less effective. Stacked graphene sheets also become rigid and lose their processability.

Some scientists have tried to physically keep the sheets apart by inserting non-carbon "spacers" between them, but that changes the chemical composition of the material. When graphene is crumpled into balls, however, its surface area remains available and the material remains pure.

"If you imagine a trash can filled with paper crumples, you really get the idea," says Jiaxing Huang, Morris E. Fine Junior Professor in Materials and Manufacturing, the lead researcher of the study. "The balls can stack up into a tight structure. You can crumple them as hard as you want, but their surface area won't be eliminated, unlike face-to-face stacking."

"Crumpled paper balls usually express an emotion of frustration, a quite common experience in research," Huang says, "However, here 'frustration' quite appropriately describes why these particles are resistant to aggregation – because their uneven surface frustrates or prevents tight face-to-face packing no matter how you process them."

To make crumpled graphene balls, Huang and his team created freely suspended water droplets containing graphene-based sheets, then used a carrier gas to blow the aerosol droplets through a furnace. As the water quickly evaporated, the thin sheets were compressed by capillary force into near-spherical particles..."

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Russia Asked to Join ExoMars Project

12:36:44 AM, Monday, October 17, 2011

"Europe has formally invited Russia to participate in space missions to Mars in 2016 and 2018.

A "yes" from the Russian space agency (Roscosmos) may be the only way of saving the missions which are at risk of cancellation due to lack of funds.

The 2016 mission involves a satellite to study the Martian atmosphere, while a big robot rover to investigate the surface is scheduled for 2018.

Both are being planned with the US, which is also struggling financially.

If Russia can be persuaded to provide a rocket to launch the 2016 satellite, it should make both atmospheric and surface ventures financially feasible.

But the European and US space agencies (Esa and Nasa) know that for Roscosmos to be interested, it will want a meaningful degree of participation.

The in-kind return for Russia would be the opportunity to provide instrumentation and technology for the missions, and for its researchers to be included in the science teams.

"Everything is open for discussion," said Esa director of science, Alvaro Gimenez.

"There are possibilities for the Russians to contribute to the rover; there may also be possibilities for them to contribute to the payload on the orbiter," he told BBC News.

"Of course, in the case of 2016, we don't have much time available to get everything on board; and in the case of 2018, we don't have much room available because it is just a single Esa/Nasa rover.

"That's why we have to start the discussions now, to see what the Russians have available and what they can develop in a fast-track."

Esa's and Nasa's joint Mars programme (known in Europe as ExoMars) has looked increasingly unsteady in recent months.

The US let it be known during the summer that it could no longer afford to provide the rocket to launch the 2016 orbiter; and Europe, which still has not raised the full funds needed for ExoMars among its member states, has no money available to buy a rocket itself..."

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Why Einstein Was Wrong About Being Wrong

12:30:30 AM, Monday, October 17, 2011

"If you want to get your mind around the research that won three astronomers the Nobel Prize in physics last week, it helps to think of the universe as a lump of dough - raisin-bread dough, to be precise - mixed, kneaded and ready to rise. Hold that thought.

Now consider Albert Einstein - not the wild-haired, elderly, absent-minded professor he became in his later years but a young, dashing scientist in his 30s. It's 1916, and he's just published his revolutionary general theory of relativity. It's not necessary to understand the theory (thank goodness). You just have to accept that it gave scientists the mathematical tools they needed to forge a better understanding of the cosmos than they'd ever had.

There was just one problem. Relativity told physicists that the universe was restless. It couldn't just sit there. It either had to be expanding or contracting. But astronomers looked, and as far as they could tell, it was doing neither. The lump of dough wasn't rising, and it wasn't shrinking.

The only way that was possible, Einstein realized, was if some mysterious force was propping up the universe, a sort of antigravity that pushed outward just hard enough to balance the gravity that was trying to pull it inward. Einstein hated this idea. An extra force meant he had to tinker with the equations of general relativity, but the equations seemed so perfect just as they were. Changing them in any way would tarnish their mathematical beauty.

Einstein did it anyway. The universe ought to behave according to the laws he had set out, but it simply wasn't cooperating. The "cosmological constant" - his name for the new antigravity force - became part of the theory.

Then, a decade or so later, the great astronomer Edwin Hubble went up to the Mount Wilson Observatory above Pasadena and used the world's most powerful telescope to peer deeper into the universe than anyone had before. Making excruciatingly careful measurements of the galaxies he could see beyond the Milky Way, Hubble was astonished to learn that they weren't stationary at all. The galaxies - the raisins in the bread dough - were in motion, each moving apart from the other. The dough was rising in all directions, and the raisins were going along for the ride..."

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NanotubeYarns Twist Like Muscles

12:25:17 AM, Monday, October 17, 2011

"Yarns made of the tiny straws of carbon called nanotubes have an astounding ability to twist as they contract, scientists have found.

The effect, reported in Science, is similar to the action of muscles found in elephant trunks and squid tentacles.

However, the yarns twist 1,000 times as much as previous "artificial muscles".

The effect, which occurs thanks to a conducting fluid in which the yarns were dipped, could be put to use in motors much thinner than a human hair.

The team of researchers from Australia, the US, Canada and South Korea demonstrated motors that could spin at nearly 600 revolutions per minute, turning a weight 2,000 times heavier than the yarn itself.

Carbon nanotubes have only recently been identified by scientists; they are "straws" made only of atoms of carbon linked together in hexagons. They have remarkable physical properties - being more than 100 times stronger than steel.

Ray Baughman of the University of Texas at Dallas is a renowned researcher into the tubes' properties, and is a co-author of the new research.

"The carbon nanotube yarns comprise invididual nanotubes - untold billions of them - that are about 1/100,000th the diameter of a human hair," he told the podcast of Science magazine.

The yarns were made by pulling sheets of nanotubes from "forests" of the tubes and twisting them to form a coiled structure - much as yarn is made from wool.

They were then dipped in an electrolyte - a fluid containing ions, electrically charged atoms. When a voltage was applied at the ends of the yarns, these ions moved into the fibres, causing them to expand..."

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Wooden Buildings Reach New Heights

12:19:28 AM, Monday, October 17, 2011

"Soon, the first tenants will start moving into a new block of council flats in Hackney in north London.

Nothing remarkable about that except Bridport House is built of wood, and it is the largest timber-built apartment block in the world.

It is possibly the biggest timber building of any kind.

Not only that, but a few hundred metres away there is another timber-built block of flats, rather smaller overall, but even taller.

Soon high-rise buildings made of wood may replace many conventional concrete and steel structures, even in the UK, a country with few forests and no modern tradition of building in wood."

-- Follow link for video.

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Could a Computer One Day Rewire Itself? New Nanomaterial 'Steers' Electric Currents in Multiple Dimensions

12:11:12 AM, Monday, October 17, 2011

"Scientists at Northwestern University have developed a new nanomaterial that can "steer" electrical currents. The development could lead to a computer that can simply reconfigure its internal wiring and become an entirely different device, based on changing needs.

As electronic devices are built smaller and smaller, the materials from which the circuits are constructed begin to lose their properties and begin to be controlled by quantum mechanical phenomena. Reaching this physical barrier, many scientists have begun building circuits into multiple dimensions, such as stacking components on top of one another.

The Northwestern team has taken a fundamentally different approach. They have made reconfigurable electronic materials: materials that can rearrange themselves to meet different computational needs at different times.

"Our new steering technology allows use to direct current flow through a piece of continuous material," said Bartosz A. Grzybowski, who led the research. "Like redirecting a river, streams of electrons can be steered in multiple directions through a block of the material -- even multiple streams flowing in opposing directions at the same time."

Grzybowski is professor of chemical and biological engineering in the McCormick School of Engineering and Applied Science and professor of chemistry in the Weinberg College of Arts and Sciences.

The Northwestern material combines different aspects of silicon- and polymer-based electronics to create a new classification of electronic materials: nanoparticle-based electronics.

The study, in which the authors report making preliminary electronic components with the hybrid material, will be published online Oct. 16 by the journal Nature Nanotechnology. The research also will be published as the cover story in the November print issue of the journal..."

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New Metal-Eating Bacteria Found on Titanic

3:23:18 AM, Saturday, October 15, 2011

"Bacteria scooped from the wreckage of the Titanic almost 20 years ago have been confirmed as a new species in the December issue of a microbiology journal.

While new scientific discoveries are usually heralded as joyous news, this discovery is bittersweet.

The bacteria, found on the ship's "rusticles" (rust formations that look like icicles), are eating the Titanic.

The strain, dubbed Halomonas titanicae, was initially designated BH1T in honor of the researchers who discovered it, then-graduate student Bhavleen Kaur and Dr. Henrietta Mann at Dalhousie University in Halifax, Canada.

The researchers tested the bacteria to see whether it was "good bacteria" or "bad bacteria," according to the school's website.

Let's just say the bug has an appetite for destruction.

"The BH1 cells stuck to the surface of these [small metal tags] and eventually destroyed the metal. So we knew we had a bad bacteria,” Mann is quoted as saying on the Dalhousie University website.

"In 1995, I was predicting that Titanic had another 30 years," said Mann, who still works at the university, according to CBS News. "But I think it's deteriorating much faster than that now ... Eventually there will be nothing left but a rust stain," she is quoted as saying.

The metal-eating bug presents a dilemma for scientists.

"Letting it proceed with its deterioration is also a learning process," said Kaur, who now works with the Ontario Science Centre, according to National Geographic. "If we stop and preserve it, then we stop the process of degradation," Kaur is quoted as saying.

The findings were published in the December 8 issue of the International Journal of Systematic and Evolutionary Microbiology.

The Titanic, heralded in its day as the largest passenger ship in the world, sank on its maiden voyage in 1912, killing more than 1,500 people. The wreckage was found in 1985 by an expedition team more than 2 miles deep in the Atlantic Ocean."

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Scientists Solve Puzzle of Black Death’s DNA

2:01:39 AM, Saturday, October 15, 2011

"After the Black Death reached London in 1348, about 2,400 people were buried in East Smithfield, near the Tower of London, in a cemetery that had been prepared for the plague’s arrival. From the teeth of four of those victims, researchers have now reconstructed the full DNA of a microbe that within five years felled one-third to one-half of the population of Western Europe.

The bacterium that causes plague, Yersinia pestis, is still highly virulent today but has different symptoms, leading some historians to doubt that it was the agent of the Black Death.

Those doubts were laid to rest last year by detection of the bacterium’s DNA in plague victims from mass graves across Europe. With the full genome now in hand, the researchers hope to recreate the microbe itself so as to understand what made the Black Death outbreak so deadly.

So far, the evidence points more toward the conditions of the time than to properties of the bacterium itself. The genome recovered from the East Smithfield victims is remarkably similar to that of the present-day bacterium, says the research team, led by Kirsten I. Bos of McMaster University in Ontario and Johannes Krause of the University of Tübingen in Germany.

This is the first time the genome of an ancient pathogen has been reconstructed, opening the way to tracking other ancient epidemics and how their microbes adapted to human hosts.

The bacterium’s genome consists of a single chromosome, about 4.6 million DNA units long, and three small rings of DNA called plasmids. In the 660 years since the Black Death struck, only 97 of these DNA units have changed and only a dozen of these changes occur in genes and therefore would affect the organism’s physical properties, the researchers report in Wednesday’s issue of the journal Nature. Dr. Krause and others reported the DNA sequence of one of the plasmids in August. The changes in the genome will be studied one by one to see how each affects the microbe’s virulence.

The researchers hope eventually to modify a living plague bacterium so that its genome is identical to that of the agent of the Black Death. Such a microbe could be handled only in special secure facilities. But even if it did infect a person, the bacterium would be susceptible to antibiotics, like its living descendants, said Hendrik Poinar of McMaster University, a team member.

If the microbe’s genome is so little changed, the deadliness of the Black Death may reflect the condition of its medieval victims. Harsh as the economic stresses assailing Europe today may be, they are a breeze compared with problems in the mid-14th century. The climate was cooling, heavy rains rotted out crops and caused frequent famines, and the Hundred Years’ War began in 1337. People were probably already suffering from malnutrition and other diseases when the plague arrived like the fourth horseman of the apocalypse. “People honestly thought it was the end of the world,” Ms. Bos said..."

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