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How Growth Hormones Work In Plants
As Wang explained: "We've known for some time what happens at the cell's surface, so understanding what is happening in the nucleus is very important for unraveling this mystery of plant growth. We found that in the model plant Arabidopsis, a protein in the cell nucleus called BZR1, which is activated when the BR hormone is present, has a previously unknown segment where molecular binding occurs. Instead of stimulating an activity, the protein binds to a DNA sequence (named brassinosteriod-response element or BRRE), which stops the process of transcription--the transfer of genetic information from the DNA template molecule to messenger RNA--for a gene named CPD. Because the CPD gene orders the production of an enzyme needed for BR synthesis, this suppression stops the production of BR conferring a feedback regulation of BR production. When the BR steroid level is high, BZR1 is activated and BR synthesis is reduced. When the level is low, the synthesis is high. This feedback regulation is critical for maintaining an optimal steroid level for plant growth......... Posted by: Jessica Permalink December 26, 2005, 5:08 PM CT Vortex In Engineered Superconductor
Preparing a scanning tunneling microscope
Knowing how the vortices move and arrange themselves under various temperatures and magnetic fields, as well as how they are influenced by the physical properties of the material, is critical in maintaining supercurrent flow. As part of Argonne's intense focus on superconductors, a team of researchers in the laboratory's Materials Science Division (MSD) has obtained, for the first time, detailed images of the interaction of magnetic vortices with artificial, nanoscale engineered defects in a superconductor. Understanding this interaction could help researchers reduce the vortices' current-sapping effects - or lead to fundamentally new superconductor designs for transmitting DC and AC electric power, and quantum logic devices based on vortex manipulation. High-temperature superconductors, discovered in 1986, have attracted intense interest due to their ability to conduct electricity without resistance when cooled with liquid nitrogen. Previously, superconductivity was only known in metals cooled with liquid helium, which is much more difficult and expensive to produce and handle. High-temperature superconductors are now used in a number of applications, including RF filters for mobile telephone networks, magnetic resonance imaging (MRI) machines and particle accelerators. A critical factor limiting applications for these superconductors is their response to magnetic fields, such as in electric motors. Magnetic fields reduce the amount of current a superconducting material can carry. The fields create swirling tubes of electrical current - vortices - in the superconducting material. Superconductivity is completely suppressed within these structures. (The individual structure of vortices and their arrangement were predicted by Alexei Abrikosov of Argonne's Materials Science Division, who won the 2003 Nobel Prize in physics for his work on superconductors.) And as current flows through the superconductor, the vortices are pushed at right angles to the current flow by the Lorentz force. The vortex movement inside the material dissipates energy and produces resistance......... Posted by: Jaison Permalink December 26, 2005, 4:48 PM CT Keys To Improving Commercial Magnet Technology
Using the Western Hemisphere's most powerful X-rays at the Advanced Photon Source at Argonne, the scientists were able to see new details of rare-earth ions, a critical component of permanent magnets. The examination of the ions, probing their magnetism with unprecedented resolution, revealed that the presence of rare-earth ions in more than one atomic environment reduces the magnetic stability of the best-performing permanent magnets to date. This knowledge will enable manufacturers to manipulate the rare-earth ion atomic structure for optimization of future magnets. The research is published this week in Physical Review Letters. Rare-earth ions come from metallic elements that share similar chemical properties; they are not particularly rare, but they are used sparingly because of the high cost in preparation of the materials. Rare-earth ions play an important role in determining magnetic stability against demagnetizing fields, and therefore in magnet performance. "The research found that rare-earth ions in dissimilar crystalline environments compete with one another, and undermine the magnetic performance of the highest performance magnets," said Argonne scientist Daniel Haskel, who led the research team. "These findings point to the need for specialized atomic engineering of the material - manipulating the rare-earth local atomic structure to fully utilize the rare-earth contribution in next generations of magnets"......... Posted by: Jaison Permalink December 26, 2005, 4:29 PM CT Recycling Automotive Plastics Is Good For The Environment
Chemist Joe Pomykala checks the flow of polyolefin coming from a tank
"About 75 percent of the weight of an obsolete car is already profitably recycled," explained Energy Systems Division Director Ed Daniels, "so we are working on the balance of that material." Developing and evaluating new process technology for industry is one of Energy Systems Division's main thrusts. Old cars and trucks end their days at dismantling facilities where usable parts are recovered. The metal is recycled next, leaving shredder residue - polyurethane foam, polymers, and some metal oxides, glass and dirt. Between 3 and 4.5 million tons of shredder residue a year ends up in landfills. Argonne is working with the American Plastics Council and the Vehicle Recycling Partnership of USCAR to develop and advance sustainable technologies for automotive materials recycling. Current research at Argonne is focused on "mechanical recycling" - recovery of materials such as plastics from shredder residue for re-use in automotive and other applications. The technology being developed at Argonne consists of two major processes. The first is a bulk separation process to separate shredder residue into constituent fractions, followed by the second process, which recovers specific plastics from a polymer concentrate. Scientists designed and installed a large-scale shredder-residue separation pilot plant at Argonne. The mechanical separation facility can process about 1 ton of shredder residue per hour. About one-third of the shredder residue - the plastic-intensive portion - is recovered as a polymer concentrate......... Posted by: Jaison Permalink December 26, 2005, 3:45 PM CT Spotlight On Dinosaurs
Dr. Phil Currie with the cranium of a Tyrannosaurus Rex
Calling his CRC in Systematics and Evolution Group the first and "long overdue pure dinosaur position" for a university in Alberta, Currie says he also looks forward to promoting dinosaur science. "Worldwide there's been very little money put into dinosaur research in the past or in the present," said Currie. "Canada is a very special place because we have some of the richest resources in the late Cretaceous anywhere in the world, and there really should be a focus on that in our museums and universities". Joining the U of A just last month, Currie has worked extensively on the discovery of feathered dinosaurs in China, meat-eating dinosaurs in Argentina, and on a pack of a dozen Albertosaurus from the badlands of central Alberta. The more than half-dozen species of feathered dinosaurs so far discovered "cover the range of meat-eating dinosaurs we have here in Alberta". Working at the Alberta Provincial Museum in the early part of 1980s, Currie helped establish the Royal Tyrrell Museum in 1985. His seven-year, $1.4 million chair will fund the continuation of his research on, among other things, the evolutionary relationship between theropod dinosaurs and their close living relatives-birds. That close relationship to birds tells us much, says Currie. Because of the theropod's similarity to birds, it is now possible, for example, to determine the sex of a theropod specimen. As the female of both the dinosaurs and birds store up calcium in their bones before laying eggs, says Currie, surplus calcium is the tell-tale sign the specimen is female......... Posted by: Jaison Permalink December 26, 2005, 3:00 PM CT Tibetan Plateau's secrets
Landslide Lake in Tibet
Several years ago, Unsworth and a team of researchers from China and the United States used low-frequency radio waves to determine that the mid-crust of the plateau is like "a big waterbed." The hot, molten rocks supporting the plateau are less dense than cold rocks, which means they rise up slowly, similar to how a hot-air balloon works. The discovery provides an explanation for how the whole of Tibet could rise up over millions of years. After that finding, Unsworth returned to Tibet and has since learned that this geological make-up is typical of the whole length of the Himalayas, not just a small region. "We initially thought that this layer might be a local structure, but it's not so," said Unsworth, a professor in the U of A Faculty of Science. His research results are published in the current edition of the scientific journal, Nature. Dubbed "the roof of the world," or the "abode of the Gods," the plateau contains not only Mount Everest but also all of the world's territory higher than 4,000 metres. The area was formed when India rammed into Asia about 50 million years ago and is considered a showcase of plate tectonics. Eventhough a number of theories have been proposed to explain the unusual thickness of the plateau-its crust doubles the average 30 to 35-kilometre thickness found the world over-little concrete evidence has been offered. Tibet was closed to foreign access until the 1980s, when French and Chinese researchers collaborated to investigate the plateau. Since then, Unsworth and his international research team have made a number of significant findings, and access to data collected in India was recently negotiated......... Posted by: Jaison Permalink December 26, 2005, 2:30 PM CT About Protecting Our Rainforests
"The traditional moral and aesthetic arguments have been made about why we should conserve the biodiversity in rainforests, but little has been done that looks at whether it makes pure economic sense to do so," said Dr. Robin Naidoo, who did his PhD at the U of A in biological sciences and rural economy. "We provide some good evidence from a strict economic side, that yes, it does". Naidoo, now with the World Wildlife Fund, and Dr. Wiktor Adamowicz, from the U of A's Department of Rural Economy, examined the costs and benefits of avian biodiversity at the Mabira Forest Reserve in southern Uganda. They wanted to see if it was economically viable to protect this forest in an area where an impoverished community is heavily dependent on the region's resources. Pressure on the forest is intense-harvesting timber, making charcoal, collecting fuel wood and agricultural development compete with rainforest conservation. An ecotourism centre has been established at the forest since 1996, and a growing number of international tourists continue to visit the reserve. Naidoo and Adamowicz found that the higher the number of bird species that could be seen, the more tourists would be willing to pay. And by increasing entrance fees, the reserve could preserve 90 per cent-or 131 species-of the forest's birds. "This is one of the few studies where people have put a tangible number on what rainforest biodiversity is worth to them," said Naidoo, adding that the benefits should be distributed to the local people bearing the conservation cost. "And eventhough this is about a Uganda forest, it has international implications"......... Posted by: Jaison Permalink December 25, 2005, 10:02 PM CT Common Houshold Detergents Good To Remove Lead
The researchers, led by Roger D. Lewis, Ph.D., CIH, of the Saint Louis University School of Public Health, tested how well various detergents removed lead from three common household surfaces: vinyl flooring, wood and wallpaper. They determined that all-purpose floor detergents containing no phosphate did just as well as a more expensive lead-specific product and trisodium phosphate (TSP), a less environmentally friendly substance. Lead-specific cleaners or TSP have long been recommended for lead removal. Of the approximately 100 million housing units in the United States, about 24 million have significant levels of lead in dust, soil or paint, according to the U.S. Department of Housing and Urban Development (HUD). New HUD guidelines, to be released in 2006, will incorporate the findings from this research, according to Lewis. The study was funded by HUD's Office of Healthy Homes and Lead Control......... Jaison Permalink December 25, 2005, 8:51 PM CT Motorcycles emit high amount of air pollutants
Especially worrisome are the high levels of hydrocarbons emitted by Japanese, German and Italian two-wheelers, according to the study. Some hydrocarbons have been linked to global warming, while others are suspected of being carcinogenic. Motorcycles aren't a primary means of transport in most developed countries, the authors note. As a consequence, they say, "the importance of [motorcycle] emissions has been underestimated in legislation, giving manufacturers little motivation to improve aftertreatment systems". Until recently, for instance, U.S. emission standards for highway motorcycles hadn't been updated in 25 years, despite the fact that these vehicles produced more harmful exhaust emissions per mile than cars or even large sports utility vehicles, according to the Environmental Protection Agency. However, a new EPA rule, which goes into effect in January, will require manufacturers to reduce combined emissions of hydrocarbons and nitrogen oxides in motorcycle exhausts by 60 percent. When the rule takes full effect in 2010, the EPA estimates it will reduce emissions of these pollutants by about 54,000 tons a year, and save approximately 12 million gallons of fuel annually by preventing it from evaporating from fuel hoses and tanks......... Jerome Permalink December 25, 2005, 8:21 PM CT Learn Color Changing From The Fish
Zebra fish
Besides unraveling some of the mysteries of human variation, the research, which is featured on the cover of the Dec. 16 issue of Science, has implications for understanding a host of human diseases including cancer, diabetes and rickets. Keith Cheng and colleagues at Pennsylvania State University (PSU) first determined the gene, called golden, regulated pigmentation in the golden zebrafish. After identifying golden in the fish, the researchers used an online database to find the gene's counterpart in humans. Such an approach was not uncommon to Cheng, who has long used zebrafish as a model organism to study cancer because of its rapid reproduction cycle and a number of genes in common with humans. When compared to the typical zebrafish, the golden variant is lighter in color and has pale stripes. The team also found the golden zebrafish had fewer, smaller melanosomes, the cellular organelles that contain the pigment melanin. The PSU group then proved the golden gene was responsible for the differences between the two zebrafish variants. People of European descent have the same melanosome characteristics as the lighter-pigmented fish--that is, fewer and smaller--suggesting to Cheng and colleagues that a golden-like gene might also be involved in human coloration. By searching a public database of human genome information, they did indeed find a very similar gene in humans. And in fact, a specific change in the human counterpart to golden was prevalent in individuals from lighter-skinned European populations, while the gene without the change corresponded to the darker pigmentation of West Africans and East Asians......... Jerome Permalink |
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