|The THEMIS Mission! |
Eco-Beavers, Space Diamonds,
Killer Wheat, New Stars in N90,
Nuclear Waste Containment?
|The THEMIS Mission!|
January 10, 2007 - On February 15, NASA will launch the largest number of scientific satellites ever sent into orbit aboard a single rocket. A handful of Alberta scientists will be at Kennedy Space Center watching and waiting. For Dr. Ian Mann and Dr. John Samson, researchers in the Department of Physics at the University of Alberta, the real fun will begin when the satellites start taking measurements in the eye of space storms above observatories spread across North America.
The satellites, all carrying identical suites of electric, magnetic, and particle detectors, are part of the NASA THEMIS mission (for "time history of events and macroscale interactions during substorms").
THEMIS is a collaborative effort of scientists from the US, Canada and Europe that will study processes occurring in near-Earth space and elsewhere in the universe.
Auroras are powered by solar wind - a stream of charged particles expelled by the sun. This wind blows past the earth at about 400-700 km per second and generates storms in the earth's magnetic environment. In the polar regions, these explode into spectacular auroral displays.
"By studying these explosions in the natural laboratory of near-Earth space, we can also learn how energy is explosively released in magnetised astrophysical objects in the universe. This also has important implications for magnetic confinement in nuclear fusion power reactors" adds Mann.
Satellite data from the THEMIS mission will be compared to observations from ground stations across the Canadian Arctic.
Since most of the readily accessible land under the northern-hemisphere auroral zone is in Canada, 16 of the 20 ground-based observatories will be set up in Canada, with the other four in Alaska. The observatories will host magnetometers which will monitor the magnetic signatures of explosions in near-Earth space known as substorms, as well as automated all-sky cameras.
The eerie glow of the northern lights seems exquisite and quite harmless. Most times, it is harmless. The display, resembling a slow-moving ribbon silently undulating in the sky, is called the aurora. It is also visible in far southern regions around the South Pole.
During substorms, the solar wind overloads the magnetosphere with too much energy and the stretched magnetic field lines snap back like an enormous slingshot, energizing and flinging electrically charged particles towards Earth. Electrons, the particles that carry electric currents in everything from TVs to cell phones, stream down invisible lines of magnetic force into the upper atmosphere over the polar regions. This stream of electrons hits atoms and molecules in the upper atmosphere, energizing them and causing them to glow with the light we know as the aurora.
Understanding what happens during substorms is important. "The worst space storms, the ones that knock-out spacecraft and endanger astronauts, could be just a series of substorms, one after the other," said David Sibeck of NASA's Goddard Space Flight Center in Greenbelt, Md., project scientist for the THEMIS mission. "Substorms could be the building block of severe space storms."
Discerning between the two proposed substorm trigger mechanisms is difficult because the magnetosphere is so large. Over Earth's night (solar wind down-stream) side, the solar wind stretches the magnetosphere far past the moon's orbit, to form the geomagnetic tail. Substorms start from a small region in space inside the geomagnetic tail, but within minutes cover a vast region of the magnetosphere. However, the two proposed trigger mechanisms predict substorm onset in distinctly different locations within the geomagnetic tail, so the key to solving this mystery lies in identifying the substorm point of origin.
January 10, 2007 - A University of Calgary professor in the Haskayne School of Business has recently published his magnum opus on the subject of procrastination – and it's only taken him 10 years.
January 10, 2006 - The humble beaver, besides claiming a spot of honor on the Canadian nickel, is also helping fellow species survive.
Though considered a pest because of the culvert-clogging dams it builds on streams, the beaver is an ally in conserving valuable wetland habitat for declining amphibian populations, a University of Alberta study shows.
The study, conducted in the boreal forests of west-central Alberta, showed that frog and toad choruses are only present on streams where beaver dams are present. While surveying the calls of male frogs and toads engaged in acoustic displays for females, researchers recorded approximately 5,000 boreal chorus frogs, wood frogs and western toads at 54 beaver ponds over a two-year period.
Pitfall traps on beaver ponds captured 5.7 times more newly metamorphosed wood frogs, 29 times more western toads and 24 times more boreal chorus frogs than on nearby free-flowing streams.
The findings could benefit amphibian conservation efforts for forestry and energy industries, by making room for beaver dams in their landscape-use plans, the researchers said.
January 9, 2007 - If indeed "a diamond is forever," the most primitive origins of Earth's so-called black diamonds were in deep, universal time, geologists have discovered. Black diamonds came from none other than interstellar space.
In a paper published online on December 20, 2006, in the journal Astrophysical Journal Letters, scientists Jozsef Garai and Stephen Haggerty of Florida International University, along with Case Western Reserve University researchers Sandeep Rekhi and Mark Chance, claim an extraterrestrial origin for the unique black diamonds, also called carbonado diamonds.
Infrared synchrotron radiation at Brookhaven National Laboratory was used to discover the diamonds' source.
"Trace elements critical to an 'ET' origin are nitrogen and hydrogen," said Haggerty. The presence of hydrogen in the carbonado diamonds indicates an origin in a hydrogen-rich interstellar space, he and colleagues believe.
The term carbonado was coined by the Portuguese in Brazil in the mid-18th century; it's derived from its visual similarity to porous charcoal. Black diamonds are found only in Brazil and the Central African Republic.
"Conventional diamonds are mined from explosive volcanic rocks [kimberlites] that transport them from depths in excess of 100 kilometers to the Earth's surface in a very short amount of time," said Sonia Esperanca, program director in the National Science Foundation's Division of Earth Sciences, which funded the research. "This process preserves the unique crystal structure that makes diamonds the hardest natural material known."
From Australia to Siberia, from China to India, the geological settings of conventional diamonds are virtually identical, said Haggerty. None of them are compatible with the formation of black diamonds.
Approximately 600 tons of conventional diamonds have been mined, traded, polished and adorned since 1900. "But not a single black/carbonado diamond has been discovered in the world's mining fields," Haggerty said.
The new data support earlier research by Haggerty showing that carbonado diamonds formed in stellar supernovae explosions. Black diamonds were once the size of asteroids, a kilometer or more in diameter when they first landed on Earth.
The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering, with an annual budget of $5.58 billion. NSF funds reach all 50 states through grants to nearly 1,700 universities and institutions. Each year, NSF receives about 40,000 competitive requests for funding, and makes nearly 10,000 new funding awards. The NSF also awards over $400 million in professional and service contracts yearly.
National Science Foundation - http://www.nsf.gov
|Wheat Kills Predators!|
By Susan A. Steeves
WEST LAFAYETTE IN January 10, 2006 — A newly identified wheat gene produces proteins that appear to attack the stomach lining of a crop-destroying fly larvae so that the bugs starve to death.
The gene's role in creating resistance to Hessian flies was a surprise to U.S. Department of Agriculture and Purdue University researchers, discoverers of the gene and its function. They made the finding as they investigated new, long-term methods to protect wheat from insect damage.
"This is a different kind of defense than we were expecting," said Christie Williams, a USDA-Agricultural Research Service scientist and Purdue Department of Entomology adjunct assistant professor. "Usually we expect the plant to fortify its cell walls or make poisons to use against insects and pathogens."
Instead, the researchers found that a specific protein, called HFR-3, one of a group of substances called lectins, is capable of binding with a carbohydrate complex in the Hessian fly larvae. The lectin acts as a key to the carbohydrate structure, known as a chitin.
When the larvae attack a resistant plant, the plant's lectin production quickly increases by as much as 3,000 times. The larvae then ingest the lectin. This interaction probably damages the larvae's chitin-rich mid-gut lining so that it can't absorb nutrients from the plant, causing the insects starve, Williams said.
Some Hessian fly larvae, which are called virulent, are capable of ridding their bodies of lectin and surviving. Avirulent larvae are unable to deactivate the lectin.
However, the researchers believe that plants resistant to Hessian fly invasions may make several strains of lectins in response to virulent larvae, Williams said.
Results of the study are published in the January issue of the journal Molecular Plant Pathology.
Researchers also discovered that not only do lectins damage the insect's mid-stomach, the lectins also taste bad and have some toxicity.
"By studying these different wheat genes, we're starting to put together a bigger picture of how Hessian fly–wheat interactions trigger resistance in the plant," Williams said. "We think that some of this has to do with the plant producing enough lectin that it just becomes so unpalatable that the insects can't feed and they starve to death."
Wheat plants that produce few or no lectins that bind to chitin are susceptible to Hessian fly larvae attack, she said. In addition, some virulent larvae can reprogram plant development so that cells in leaves and the base of the plant where the insects feed pump out nutrients favored by the insect. If this happens then even the weak, avirulent larvae on the same leaf have a chance to survive.
To advance their investigation into developing more resistant plants, the researchers are beginning work on a single microchip that would be an array of genes from both the Hessian fly and wheat. This will allow the scientists to study insect-plant interactions. Knowing the timing and location of those interactions would enable the scientists to use the promoter tactic only in the vegetative parts of the wheat plant rather than in the head or grain portions. This will protect the grain quality and the consumer.
|Milky Way's Black Hole Lights Up!|
January 10, 2007 - Like cold case investigators, astronomers have used NASA's Chandra X-ray Observatory to uncover evidence of a powerful outburst from the giant black hole at the Milky Way's center.
A light echo was produced when X-ray light generated by gas falling into the Milky Way's supermassive black hole, known as Sagittarius A* (pronounced "A-star"), was reflected off gas clouds near the black hole. While the primary X-rays from the outburst would have reached Earth about 50 years ago, the reflected X-rays took a longer path and arrived in time to be recorded by Chandra.
"This dramatic event happened before we had satellites in space that could detect it," said Michael Muno of the California Institute of Technology in Pasadena. "So, it's remarkable that we can use Chandra to dig into the past and see this monster black hole's capacity for destruction."
Previously, scientists have used Chandra to directly detect smaller and more recent outbursts from the black hole. This latest outburst revealed by the X-ray echo was about 1,000 times brighter and lasted well over 1,000 times longer than any of the recent outbursts observed by Chandra.
Theory predicts that an outburst from Sagittarius A* would cause X-ray emission from the clouds to vary in both intensity and shape. Muno and his team found these changes for the first time, thus ruling out other interpretations. The latest results corroborate other independent, but indirect, evidence for light echoes generated by the black hole in the more distant past.
Scientists have long known that Sagittarius A*, with a mass of about 3 million suns, lurked at the center for Milky Way. However, the black hole is incredibly faint at all wavelengths, especially in X-rays.
"This faintness implies that stars and gas rarely get close enough to the black hole to be in any danger," said co-author Frederick K. Baganoff of the Massachusetts Institute of Technology in Cambridge. "The huge appetite is there, but it's not being satisfied."
During the outburst, the area close to the black hole would have been about 100,000 times brighter than it is currently. If such an outburst had occurred more recently, it likely would have been detected by an X-ray instrument, or would have produced similar features in other nearby clouds.
|New Stars in N90!|
January 8, 2007 - A new image from the Hubble Space Telescope shows N90, one of the star-forming regions in the Small Magellanic Cloud. The rich populations of infant stars found here enable astronomers to examine star forming processes in an environment that is very different from that in our own Milky Way.
This new image taken with the Advanced Camera for Surveys onboard the NASA/ESA Hubble Space Telescope depicts bright blue newly formed stars that are blowing a cavity in the centre of a fascinating star-forming region known as N90.
N90 is located in the wing of the Small Magellanic Cloud, in the constellation of Tucana, approximately 200,000 light-years away from the Earth. Its proximity makes it an exceptional laboratory to perform in-depth studies of star formation processes and their evolution in an environment close to that in the early Universe.
Dwarf galaxies such as the Small Magellanic Cloud, with small numbers of stars compared to our own Milky Way, are considered to be the primitive building blocks of larger galaxies. The study of star formation within this dwarf galaxy is particularly interesting to astronomers because its primitive nature means that it lacks a large percentage of the heavier elements that are forged in successive generations of stars through nuclear fusion.
The high energy radiation blazing out from the hot young stars in N90 is eroding the outer portions of the nebula from the inside, as the diffuse outer reaches of the nebula prevent the energetic outflows from streaming away from the cluster directly. Because N90 is located far from the central body of the Small Magellanic Cloud, numerous background galaxies in this picture can be seen, delivering a grand backdrop for the stellar newcomers. The dust in the region gives these distant galaxies a reddish-brown tint.
Hubble has often been used to observe star birth regions, but they are rarely as stunning and fascinating as N90. At the heart of N90 lies NGC 602, a relatively isolated star cluster whose environment is a close analogue to what existed in the early Universe. The existence of dark clouds of dense dust and the cluster being rich in ionized gas suggest the presence of ongoing star formation processes.
Ridges of dust and gaseous filaments are seen towards north-west (in the upper left part of the image) and towards south-east (in the lower right hand corner). Magnificent elephant trunk-like dust pillars point towards the hot blue stars and are tell-tale signs of their eroding effect.
An international team of astronomers, led by Antonella Nota of the European Space Agency and the Space Telescope Science Institute in the US, has discovered a population of small newborn stars scattered across the picture. Observable around the bright blue stars at the centre of the image, these stars have caught astronomers’ attention because they are still forming from gravitationally collapsing gas clouds. Furthermore, they have not yet contracted to the point where their cores are hot enough to begin converting hydrogen into helium.
In this region it is possible with Hubble to trace how the star formation started at the centre of the cluster and propagated outwards, with the youngest stars still forming today along the dust ridges.
This image was presented by Lynn Redding Carlson, Johns Hopkins University, at the 2007 January meeting of the American Astronomical Society in Seattle.
ESA/Hubble Information Centre - http://www.spacetelescope.org
|Snap Decisions More Reliable?|
|University College London News Release |
January 8, 2007 - A UCL (University College London) study has found that you are more likely to perform well if you do not think too hard and instead trust your instincts. The research, published online today in the journal Current Biology, shows that, in some cases, instinctive snap decisions are more reliable than decisions taken using higher-level cognitive processes.
Participants, who were asked to pick the odd one out on a screen covered in over 650 identical symbols, including one rotated version of the same symbol, actually performed better when they were given no time at all to linger on the symbols and so were forced to rely entirely on their subconscious.
Dr Li Zhaoping, of the UCL Department of Psychology, said: "This finding seems counter-intuitive. You would expect people to make more accurate decisions when given the time to look properly. Instead they performed better when given almost no time to think. The conscious or top-level function of the brain, when active, vetoes our initial subconscious decision – even when it is correct – leaving us unaware or distrustful of our instincts and at an immediate disadvantage. Falling back on our inbuilt, involuntary subconscious processes for certain tasks is actually more effective than using our higher-level cognitive functions."
The study shows an instance when our rational mind is more likely to perform worse than our subconscious – but the conscious mind still tends to veto the subconscious.
Ten participants were asked to locate the only back to front version of a repeated symbol on screen and were given between zero and 1.5 seconds from the moment their eyes had landed on the odd one out to scrutinize the image. Participants had to decide whether the odd one out was on the left or the right-hand side of the screen. The researchers found that participants scored better if they were given no scrutinizing time at all.
With only a tiny fraction of a second for scrutinizing the target, subjects performed with 95 per cent accuracy. With over a second to scrutinize the image, subjects were only 70 per cent accurate. With more than four seconds, accuracy was recovered.
|Nuclear Waste Containment Flawed?|
January 10, 2007 - Minerals intended to entrap nuclear waste for hundreds of thousands of years may be susceptible to structural breakdown within 1,400 years, a team from the University of Cambridge and the Pacific Northwest National Laboratory reported today (Jan. 11) in the journal Nature.
The new study used nuclear magnetic resonance, or NMR, to show that the effects of radiation from plutonium incorporated into the mineral zircon rapidly degrades the mineral's crystal structure.
This could lead to swelling, loss of physical strength and possible cracking of the mineral as soon as 210 years, well before the radioactivity had decayed to safe levels, said lead author and Cambridge earth scientist Ian Farnan.
According to current thinking, highly radioactive substances could be rendered less mobile by combining them, before disposal, with glass or with a synthetic mineral at a very high temperature to form a crystal.
However, the crystal structure can only hold the radioactive elements for so long. Inside the crystal radioactive decay occurs, and tiny atomic fragments called alpha particles shoot away from the decaying nucleus, which recoils like a rifle, with both types repeatedly blasting the structure until it breaks down.
This may increase the likelihood for radioactive materials to leak, although co-author William J. Weber, a fellow at the Department of Energy national laboratory in Richland, Wash., who made the samples used in the study, cautioned that this work did not address leakage, and researchers detected no cracking. Weber noted that the "amorphous," or structurally degraded, natural radiation-containing zircon can remain intact for millions of years and is one of the most durable materials on earth.
Some earth and materials scientists believe it is possible to create a structure that rebuilds itself after these "alpha events" so that it can contain the radioactive elements for much longer. The tests developed by the Cambridge and PNNL team would enable scientists to screen different mineral and synthetic forms for durability.
As well as making the storage of the waste safer, new storage methods guided by the NMR technique could offer significant savings for nations facing disposal of large amounts of radioactive material. Countries including the United States, Britain, France, Germany and Japan are all considering burying their nuclear waste stockpiles hundreds of meters beneath the earth's surface. Doing so necessitates selection of a site with sufficiently stringent geological features to withstand any potential leakage at a cost of billions of dollars. For example, there is an ongoing debate over the safety of the Yucca Mountain site in Nevada. A figure published in Science in 2005 put that project's cost at $57 billion.
"By working harder on the waste form before you started trying to engineer the repository or choose the site, you could make billions of dollars worth of savings and improve the overall safety," Farnan said.