February 6, 2008, 10:26 PM CT

New, practical dimension to holography

University of Arizona optical researchers have broken a technological barrier by making three-dimensional holographic displays that can be erased and rewritten in a matter of minutes.

The holographic displays which are viewed without special eyewear are the first updatable three-dimensional displays with memory ever to be developed, making them ideal tools for medical, industrial and military applications that require "situational awareness".

"This is a new type of device, nothing like the tiny hologram of a dove on your credit card," UA optical sciences professor Nasser Peyghambarian said. "The hologram on your credit card is printed permanently. You cannot erase the image and replace it with an entirely new three-dimensional picture".

"Holography has been around for decades, but holographic displays are really one of the first practical applications of the technique," UA optical scientist Savas Tay said.

Dynamic hologram displays could be made into devices that help surgeons track progress during lengthy and complex brain surgeries, show airline or fighter pilots any hazards within their entire surrounding airspace, or give emergency response teams nearly real-time views of fast-changing flood or traffic problems, for example.

And no one yet knows where the advertising and entertainment industries will go with possible applications, Peyghambarian said. "Imagine that when you walk into the supermarket or department store, you could see a large, dynamic, three-dimensional product display," he said. It would be an attention-grabber......... Posted by: Ethen      Read more         Source

February 6, 2008, 9:37 PM CT

Racing Ahead at the Speed of Light

Imagine trying to catch up to something moving close to the speed of light - the fastest anything can move - and sending ahead information in time to make mid-path flight corrections. Impossible? Not quite. Physicists at the Relativistic Heavy Ion Collider (RHIC), a particle accelerator at the U.S. Department of Energy's Brookhaven National Laboratory, have achieved this tricky task - and the results may save the Lab money and time in their quest to understand the inner workings of the early universe.

The physicists have developed a way to measure subtle fluctuations in RHIC's particle beams as they speed around their 2.4-mile-circumference high-tech racetrack - and send that information ahead to specialized devices that smooth the fluctuations when the beam arrives.

"These corrections help to keep the beams focused and colliding, recreating thousands of times a second the conditions that existed just after the Big Bang," said Steven Vigdor, Brookhaven Lab's Associate Laboratory Director for Nuclear and Particle Physics, who manages the RHIC program.

Already, RHIC scientists have learned that mere microseconds after the Big Bang, the universe was more interesting than imagined - a nearly "perfect" liquid with virtually no viscosity and strong interactions among its constituents. With the ability to race ahead of RHIC's beams and keep them focused, the scientists will be able to create many more "mini-Bangs" for study. The increase in data will help them investigate and measure the detailed properties of this "perfect" liquid, and test certain predictions stimulated by an unanticipated link between RHIC findings and "string theory," an appealing approach to incorporate gravity into a unified theory that describes all of Nature's forces......... Posted by: Beverly      Read more         Source

January 29, 2008, 9:55 PM CT

New Antarctic Ice Core to Provide Clearest Climate Record

After enduring months on the coldest, driest and windiest continent on Earth, scientists today closed out the inaugural season on an unprecedented, multi-year effort to retrieve the most detailed record of greenhouse gases in Earth's atmosphere over the last 100,000 years.

Working as part of the National Science Foundation's West Antarctic Ice Sheet Divide (WAIS Divide) Ice Core Project, a team of scientists, engineers, technicians and students from multiple U.S. institutions have recovered a 580-meter (1,900-foot) ice core--the first section of what is hoped to be a 3,465-meter (11,360-foot) column of ice detailing 100,000 years of Earth's climate history, including a precise year-by-year record of the last 40,000 years.

The dust, chemicals and air trapped in the two-mile-long ice core will provide critical information for researchers working to predict the extent to which human activity will alter Earth's climate, as per the chief scientist for the project, Kendrick Taylor of the Desert Research Institute of the Nevada System of Higher Education. DRI, along with the University of New Hampshire, operate the Science Coordination Office for the WAIS Divide Project.

WAIS Divide, named for the high-elevation region that is the boundary separating opposing flow directions on the ice sheet, is the best spot on the planet to recover ancient ice containing trapped air bubbles--samples of the Earth's atmosphere from the present to as far back as 100,000 years ago......... Posted by: Beverly      Read more         Source

January 29, 2008, 9:21 PM CT

Agriculture is changing the chemistry of the Mississippi

Midwestern farming has introduced the equivalent of five Connecticut Rivers into the Mississippi River over the past 50 years and is adding more carbon dioxide annually into its waters, according to a study published in Nature by researchers at Yale and Louisiana State universities.

Its like the discovery of a new large river being piped out of the corn belt, said Pete Raymond, lead author of the study and associate professor of ecosystem ecology at the Yale School of Forestry & Environmental Studies. Agricultural practices have significantly changed the hydrology and chemistry of the Mississippi River.

The researchers tracked changes in the levels of water and bicarbonate, which forms when carbon dioxide in soil water dissolves rock minerals. Bicarbonate plays an important, long-term role in absorbing atmospheric carbon dioxide, a greenhouse gas. Oceans then absorb the excess carbon dioxide and become more acidic in the process. Ocean acidification makes it more difficult for organisms to form hard shells in coral reefs, said R. Eugene Turner, a co-author of the study and a professor at the Coastal Ecology Institute at Louisiana State University.

The researchers concluded that farming practices, such as liming, changes in tile drainage and crop type and rotation, are responsible for the majority of the increase in water and carbon dioxide in the Mississippi River, which is North Americas largest river......... Posted by: Beverly      Read more         Source

January 28, 2008, 10:22 PM CT

Factors Contributing to DNA Mutations

A team of Penn State University scientists is the first to conduct a genome-wide study to compare the relative importance of factors that contribute to DNA mutations, which are implicated in cancer and over 40 neurological disorders. Led by assistant professor of biology Kateryna Makova, the group investigated the simultaneous effects of numerous factors that are thought to increase the susceptibility to mutations of microsatellites -- variable-length sequences of recurring DNA subunits. Microsatellites are common throughout the genomes of plants and animals. The work is described in the January 2008 issue of the journal Genome Research.

Results of the team's analysis could have several applications. "Our statistical analysis may be useful in predicting which disease-causing microsatellites are likely to have high rates of de novo mutations," said Makova. De novo mutations are those that occur for the first time in a family.

In addition to being of value to medical geneticists, Makova said the results may be useful to forensics experts and conservation geneticists. Because microsatellites are highly variable among individuals in healthy populations, they can be used by forensics experts to identify criminals. Similarly, conservation geneticists can use a lack of microsatellite variability among individuals in a group to distinguish populations that are threatened with low genetic diversity. By identifying the most important factors contributing to microsatellite mutability -- the microsatellite's ability to mutate -- the team's research may help researchers to pinpoint microsatellites that are especially important for their area of research......... Posted by: Beverly      Read more         Source

January 24, 2008, 11:16 PM CT

Team IDs weakness in anthrax bacteria

MIT and New York University scientists have identified a weakness in the defenses of the anthrax bacterium that could be exploited to produce new antibiotics.

The scientists observed that nitric oxide (NO) is a critical part of Bacillus anthracis's defense against the immune response launched by cells infected with the bacterium. Anthrax bacteria that cannot produce NO succumb to the immune system's attack.

Stephen Lippard, the Arthur Amos Noyes Professor of Chemistry at MIT and an author of a paper on the work, said antibiotics developed to capitalize on this vulnerability could be effective against other bacteria that employ the same defense system. Those bacteria include Staphylococcus aureus, which usually causes infections in hospitals and can be extremely drug-resistant.

The paper appeared in the Jan. 21 online edition of the Proceedings of the National Academy of Sciences.

Anthrax occurs naturally around the world and can infect all warm-blooded animals including humans. Treatment commonly includes large doses of intravenous and oral antibiotics, but the disease can often be fatal--particularly if therapy is not started right away.

In the human immune system, specialized cells called macrophages are the first line of defense against anthrax infection. Macrophages engulf the bacteria and bombard them with reactive oxygen and nitrogen species, which create chemical reactions toxic to the bacteria......... Posted by: Beverly      Read more         Source

January 14, 2008, 5:37 PM CT

Teen pregnancy for dinosaurs

Dinosaurs descended from reptiles and evolved into today's birds, but their growth and sexual maturation were more like that of mammals - complete with teen pregnancy, as per a new study by University of California, Berkeley, scientists.

Though dinosaurs grew for much of their lives, they experienced a rapid growth spurt in adolescence, like mammals, said UC Berkeley graduate student Sarah Werning. She and Andrew H. Lee, a recent UC Berkeley Ph.D. recipient who is currently a postdoctoral fellow at Ohio University's College of Osteopathic Medicine in Athens, Ohio, have now shown that dinosaurs reached sexual maturity near the end of this rapid growth phase, well before reaching maximum body size. Medium-to-large mammals, including humans, also are able to reproduce before they finish growing.

The finding, Werning said, suggests that dinosaurs were born precocious and suffered high adult mortality, making early sexual maturity necessary for survival.

"This is an exciting finding, because age at sexual maturity is correlation to so a number of things," said the students' advisor, Kevin Padian, who is a professor of integrative biology and a curator in UC Berkeley's Museum of Paleontology. "It also shows that you can't use reptiles as a model for dinosaur growth, as a number of researchers still do"......... Posted by: Beverly      Read more         Source

Wed, 09 Jan 2008 04:01:48 GMT

Hamamelis Intermedia 'Fireglow'

May as well start the new year with fireworks....

I''ve previously written about Hamamelis ×intermedia ''Fireglow'', so I''ll refer you to that entry today while I continue to enjoy a sliver of time off after madly rushing to submit the John Davidson web site for review by the end of the December. It should be available for public viewing sometime in February, if all goes well.

For those readers of today''s Vancouver Sun article, “No One-Hit Wonder”, welcome! My suggestion is to start your visit by checking out the main Botany Photo of the Day page and the main UBC Botanical Garden Forums page, and explore from there! Posted by: Daniel Mosquin      Read more     Source

January 3, 2008, 9:39 PM CT

A crystal that nature may have missed

For centuries, human beings have been entranced by the captivating glimmer of the diamond. What accounts for the stunning beauty of this most precious gem? As mathematician Toshikazu Sunada explains in an article appearing today in the Notices of the American Mathematical Society, some secrets of the diamond's beauty can be uncovered by a mathematical analysis of its microscopic crystal structure. It turns out that this structure has some very special, and particularly symmetric, properties. In fact, as Sunada discovered, out of an infinite universe of mathematical crystals, only one other shares these properties with the diamond, a crystal that he calls the "K_4 crystal". It is not known whether the K_4 crystal exists in nature or could be synthesized.

One can create an idealized mathematical model of a crystal by focusing on its main features, namely, the atoms and the bonds between them. The atoms are represented by points, which we will call "vertices", and the bonds are represented as lines, which we will call "edges". This kind of network of vertices and edges is called a "graph". A crystal is built up by starting with a building-block graph and joining together copies of itself in a periodic fashion. Thus there are two patterns operating in a crystal: The pattern of edges connecting vertices in the building-block graphs (that is, the pattern of bonding relations between the atoms), and the periodic pattern joining the copies of the graphs. One can create infinitely a number of mathematical crystals this way, by varying the graphs and by varying the way they are joined periodically......... Posted by: Beverly      Read more         Source

Thu, 20 Dec 2007 05:07:18 GMT

A Puzzle, Even to Poincare and Picasso

These great thinkers usually report being mere onlookers to their own mental processes. They seem unable to identify what prompted their discoveries and even, when they''re actually happening.

The problem is that these reports were usually made many years after the original thought processes. Picasso may simply have forgotten what prompted him to create the first ever cubist painting ''Les Demoiselles d''Avignon'' (detail above). Perhaps if we''d asked him exactly what was going through his mind right after he painted it, the answer would have been more accurate.

A classic psychology study from 1931 suggests, though, that he still wouldn''t have been able to tell us what was going on in his mind. This experiment neatly demonstrates how we often don''t have a clue how we solve a problem.

The two cord puzzle
Way back in 1931 Norman Maier at the University of Michigan wanted to explore how people solve problems (Maier, 1931). To do this he attached two cords to the ceiling of his lab and asked people to tie the two ends together. What made it tricky was that the two cords were just far enough apart that, while holding on to one cord, you couldn''t reach the other cord.

To help participants out he placed some objects around the room which people were allowed to use. There were extension cords, poles, clamps, weights and so on. Most people worked out pretty quickly that tying an extension cord to one of the cords would solve the problem, as would using a pole. These seemingly obvious answers didn''t satisfy Maier though; he was looking for something much more simple and elegant.

So what he did was keep asking people to come up with new solutions. When they attached the extension cord, he''d say: "OK, now do it a different way." And he kept doing this until they ran out of new solutions. Then most people just stood there, stumped.

Perhaps you can work out the solution. Remember, there are two cords. They''re just too far apart for you to reach one while holding the other one. You can use one of the items I''ve already mentioned as being in the room but you can''t bend the fundamental laws of the universe or get tricksy. So, no growing longer arms or unweaving the cord to make it longer.

Don''t read on if you''re playing along at home!

The solution
The answer, when you hear it, often provokes forehead slapping, although most people don''t get it until prompted. The answer is to attach a weight to one of the cords and set it swinging. Then you grab the other rope and can reach the swinging rope when it comes towards you.

If you got it, well done - that''s very unusual. Most people need a clue and that is what Maier eventually gave his flummoxed participants. Throughout the experiment he would be casually walking around the room until, when people had run out of solutions, he would apparently accidentally brush against one of the ropes and set it swinging.

Almost invariably people would work out the solution above in under a minute of this apparently accidental clue.

How did you solve it?
The experiment is a neat way of showing how effectively we can be primed with a solution to a problem. But the question we''re really interested in is whether we know where the solution comes from. Did Maier''s participants realise they''d been given a hint?

The answer was, on the whole, no.

When they were interviewed afterwards only one-third of his participants realised he''d given them a massive clue by setting one of the ropes swinging. Most people told some, often quite creative, stories about how they had reached the solution. These stories may well have accurately represented their conscious experience, but were clearly not the real reason why they solved the problem.

But when we take a close look at the experiment, it''s worse than that.

Fake clues
The rope swinging wasn''t the only clue that Maier used in the experiment. He had another hint which was twirling a weight on a cord. He soon found, though, that this hint was useless - it didn''t help anyone solve the puzzle. Despite this everyone who saw the dangling weight first reported that it was this that had triggered their solution not his ''accidental'' brushing of one of the cords.

What this suggests is that even those people who identified Maier''s cord brushing as the really effective clue may have just been guessing.

The power of the unconscious
This experiment, along with others that have been conducted since, tell us that we often know little about how we solve problems, indeed generally how we think. So perhaps the best advice for how to solve problems is that provided by the great novelist Henry James, brother of the famous psychologist William James:
"I was charmed with my idea, which would take, however, much working out; and because it had so much to give, I think, must I have dropped it for the time into the deeper well of unconscious cerebration: not without the hope, doubtless, that it might eventually emerge from that reservoir, as one had already known the buried treasure to come to light, with a firm iridescent surface and a notable increase of weight" (Ghiselin, 1952, p. 26). Posted by: Jerry      Read more     Source