Monday, June 21, 2010

SLEEP COLORS YOUR VIEW OF THE WORLD: STUDY SUGGESTS SLEEP MAY RESTORE COLOR PERCEPTION

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Color perception drifts away from neutrality during wakefulness and is restored during sleep, suggests a research abstract that was presented Wednesday, June 9, 2010, in San Antonio, Texas, at SLEEP 2010, the 24th annual meeting of the Associated Professional Sleep Societies LLC.

Results indicate that prior wakefulness caused the color gray to be classified as having a slightly but significantly greenish tint. Overnight sleep restored perception to achromatic equilibrium so that gray was perceived as gray.

According to the authors, scientists had not previously investigated how sleep might affect the way we view the world around us.

"This is among the first studies to investigate the effects of sleep on perception," said principal investigator and lead author Bhavin Sheth, assistant professor of electrical and computer engineering at the University of Houston in Texas. "Our findings suggest that wakefulness causes color classification to drift away from neutrality, and sleep restores color classification to neutral."

The study involved five people who viewed a full-field, homogenous stimulus of either slightly reddish or greenish hue. The observers had to judge whether the stimulus was greener or redder than their internal perception of neutral gray. Across trials the hue was varied. One pair of monocular tests was performed just before participants went to sleep, and testing was repeated after participants slept for an average of 7.7 hours.

Further testing found that overnight, full-field monocular stimulation with a flickering red "ganzfeld" failed to nullify the resetting, sleep-induced effect. An achromatic stimulus was still less likely to be classified as greenish following sleep, with no statistical difference in the magnitude of the resetting in each eye. According to the authors, this suggests that color resetting is an internal process that is largely unaffected by external monochromatic visual stimulation.

American Academy of Sleep Medicine

MAN-MADE AURORA TO HELP PREDICT SPACE WEATHER

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For more than 25 years, our understanding of terrestrial space weather has been partly based on incorrect assumptions about how nitrogen, the most abundant gas in our atmosphere, reacts when it collides with electrons produced by energetic ultraviolet sunlight and "solar wind."

New research published Tuesday 8 June, in IOP Publishing's Journal of Physics B: Atomic, Molecular and Optical Physics describes how scientists from NASA's Jet Propulsion Laboratory (JPL) at the California Institute of Technology have fired electrons of differing energies through a cloud of nitrogen gas to measure the ultraviolet light emitted by this collision.

The researchers have found that well-trusted measurements published in a 1985 journal paper by researchers Ajello and Shemansky contain a significant experimental error, putting decades of space weather findings dependent on this work on unstable ground.

The difference between these contemporary findings and the 1985 researchers' work stems from the 2010 team's improved ability to create and control the collisions and avoid the analytical pitfalls that plagued the 1985 findings.

The new results from the team at JPL suggest that the intensity of a broad band of ultraviolet light emitted from the collision changes significantly less with bombarding electron energies than previously thought.

As the ultraviolet light within the so called 'Lyman-Birge-Hopfield' (LBH) band is used by the likes of NASA and the European Space Agency to better understand the physical and chemical processes occurring in our upper atmosphere and in near-Earth space, the results will give some immediate cause to reflect.

With near-Earth space playing host to our ever-growing satellite communication systems, the new more accurate measurements might unleash a greater understanding of space weather and help us better protect our space-based assets.

The findings will also help further our understanding of phenomena like Aurora Borealis (the Northern Lights) and similarly the Aurora Australis (Southern Lights), which are caused by collisional processes involving solar wind particles exciting terrestrial oxygen and nitrogen particles at the North and South Pole.

The researchers are hopeful that their findings will also assist the Cassini project understand happenings on Saturn's largest moon, Titan, as LBH emissions have been detected by the orbiting robotic spacecraft.

Author Dr Charles Patrick Malone from JPL said, "Our measurement of LBH energy-dependence differs significantly from widely accepted results published 25 years ago. Aeronomers can now turn the experiment around and apply it to atmospheric studies and determine what kind of collisions produce the observed light."

Institute of Physics

BACTERIA FROM HOT SPRINGS REVEAL CLUES TO EVOLUTION OF EARLY LIFE AND TO UNLOCK BIOFUELS' POTENTIAL

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A bacteria that lives in hot springs in Japan may help solve one of the mysteries of the early evolution of complex organisms, according to a study publishing in PLoS Biology. It may also be the key to 21st century biofuel production.

Thermosynechococcus elongatus, a cyanobacterium that can survive at temperatures up to 150 degrees Fahrenheit, after they noticed an unusually high percentage of the bacteria's genetic sequence was composed of elements known as group II introns.

"Introns are mysterious elements in evolution," says Lambowitz, a professor of molecular biology and director of the Institute of Molecular and Cellular Biology. "Until the 1970s it was believed that genes in all organisms would be continuous and that they would make a continuous RNA, which would then get translated into a continuous protein. It was found, however, that most genes of the eukaryotes, the higher organisms including humans, aren't like that at all. Most of the genes in higher organism are discontinuous. They consist of DNA coding regions that are separated by areas known as introns.

"Genomes become loaded down with these introns, which are thought to have evolved from genomic parasites that existed for their own benefit and could spread without killing the host organism," says Lambowitz. "It remains a major question in evolution as to why these introns exist, and how they came to compose such a large part of the human genome."

In order to better understand the early history of introns, Lambowitz and Mohr have focused their investigation on bacteria because they're believed to be the original evolutionary wellspring of the introns. They're looking at T. elongatus in particular because it's the only known bacteria in which introns have proliferated in a manner similar to that in higher organisms, such as humans.

"We can't go back a billion years in a time machine to see how introns proliferated in the early eukaryotes," says Mohr, a research scientist in Lambowitz's lab. "What we can do is investigate the mechanisms that have allowed introns to proliferate in this organism, and try to infer how they evolved in eukaryotes, like humans, in which as much as 40 percent of the genome is made up of introns."

Among the mechanisms they've identified, perhaps the most surprising has been that heat plays a significant role in allowing introns to proliferate in T. elongatus. High temperatures, like those found in the hot springs in which the bacteria live, can unwind the DNA strands in the genome and make it easier for the introns to insert themselves.

This evidence of "DNA melting," says Lambowitz, is particularly suggestive when trying to imagine how introns proliferated in early eukaryotes, because the earth was hotter a billion or so years ago, when the early eukaryotes emerged. The genomes of the early eukaryotes may have begun with only a few introns, but over time, thanks in part to the high temperatures, the introns could have proliferated rapidly.

Lambowitz and Mohr's investigation of introns in T. elongatus may also, unexpectedly, prove an enormous boon to researchers who are trying to use other high-temperature ("thermophilic") bacteria to improve the efficiency of biofuels.

"There's one bacterial species in particular," says Lambowitz, "which lives at high temperature and is very good at converting cellulose to ethanol, but has been intractable to genetic manipulation. The Department of Energy has a considerable amount of money invested in it, and they need to improve the strains but haven't been able to do it. When we discovered these thermophilic introns, which work better at high temperatures, we were able to adapt them pretty rapidly for gene targeting."

The technology for using group II introns in gene targeting, known as targetron technology, was pioneered by Lambowitz and his coworkers. Lambowitz and Mohr are already working with scientists at Oak Ridge National Laboratory to see if they can successfully genetically engineer thermophilic bacteria for increased biofuel production. They also foresee applying what they've discovered about T. elongatus introns and temperature to a whole range of biotech and biomedical applications that involve organisms and enzymes that function best at high temperatures. However, they are still planning to delve further into the more profound, basic scientific questions that drew them to the subject in the first place.

Public Library of Science (PLoS)

VIOLENT VIDEO GAMES MAY INCREASE AGGRESSION IN SOME BUT NOT OTHERS

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Playing violent video games can make some adolescents more hostile, particularly those who are less agreeable, less conscientious and easily angered. But for others, it may offer opportunities to learn new skills and improve social networking.

In a special issue of the journal Review of General Psychology, published in June by the American Psychological Association, researchers looked at several studies that examined the potential uses of video games as a way to improve visual/spatial skills, as a health aid to help manage diabetes or pain and as a tool to complement psychotherapy. One study examined the negative effects of violent video games on some people.

"Much of the attention to video game research has been negative, focusing on potential harm related to addiction, aggression and lowered school performance," said Christopher J. Ferguson, PhD, of Texas A&M International University and guest editor of the issue. "Recent research has shown that as video games have become more popular, children in the United States and Europe are having fewer behavior problems, are less violent and score better on standardized tests. Violent video games have not created the generation of problem youth so often feared."

In contrast, one study in the special issue shows that video game violence can increase aggression in some individuals, depending on their personalities.

In his research, Patrick Markey, PhD, determined that a certain combination of personality traits can help predict which young people will be more adversely affected by violent video games. "Previous research has shown us that personality traits like psychoticism and aggressiveness intensify the negative effects of violent video games and we wanted to find out why," said Markey.

Markey used the most popular psychological model of personality traits, called the Five-Factor Model, to examine these effects. The model scientifically classifies five personality traits: neuroticism, extraversion, openness to experience, agreeableness and conscientiousness.

Analysis of the model showed a "perfect storm" of traits for children who are most likely to become hostile after playing violent video games, according to Markey. Those traits are: high neuroticism (e.g., easily upset, angry, depressed, emotional, etc.), low agreeableness (e.g., little concern for others, indifferent to others feelings, cold, etc.) and low conscientiousness (e.g., break rules, don't keep promises, act without thinking, etc.).

Markey then created his own model, focusing on these three traits, and used it to help predict the effects of violent video games in a sample of 118 teenagers. Each participant played a violent or a non-violent video game and had his or her hostility levels assessed. The teenagers who were highly neurotic, less agreeable and less conscientious tended to be most adversely affected by violent video games, whereas participants who did not possess these personality characteristics were either unaffected or only slightly negatively affected by violent video games.

"These results suggest that it is the simultaneous combination of these personality traits which yield a more powerful predictor of violent video games," said Markey. "Those who are negatively affected have pre-existing dispositions, which make them susceptible to such violent media."

"Violent video games are like peanut butter," said Ferguson. "They are harmless for the vast majority of kids but are harmful to a small minority with pre-existing personality or mental health problems."

The special issue also features articles on the positives of video game play, including as a learning tool. For example:

*Video games serve a wide range of emotional, social and intellectual needs, according to a survey of 1,254 seventh and eighth graders. The study's author, Cheryl Olson, PhD, also offers tips to parents on how to minimize potential harm from video games (i.e., supervised play, asking kids why they play certain games, playing video games with their children).

*Commercial video games have been shown to help engage and treat patients, especially children, in healthcare settings, according to a research review by Pamela Kato, PhD. For example, some specially tailored video games can help patients with pain management, diabetes treatment and prevention of asthma attacks.

*Video games in mental health care settings may help young patients become more cooperative and enthusiastic about psychotherapy. T. Atilla Ceranoglu, M.D., found in his research review that video games can complement the psychological assessment of youth by evaluating cognitive skills and help clarify conflicts during the therapy process.

American Psychological Association

NO PLACE TO HIDE

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Traditional surveillance cameras can be of great assistance to law enforcement officers for a range of scenarios—canvassing a crowd for criminal activity, searching for who left a suitcase beneath a bench, or trying to pick out a suspect who has fled a crime scene and blended into a teeming throng in the subway.

But there are shortfalls. For starters, once they zoom in on a specific point of interest, they lose visual contact with the rest of the scene.

Now, a new video surveillance system currently being developed by the Department of Homeland Security's Science and Technology Directorate (S&T) may soon give law enforcement an extra set of eyes. The Imaging System for Immersive Surveillance (or ISIS) takes new video camera and image-stitching technology and bolts it to a ceiling, mounts it on a roof, or fastens it to a truck-mounted telescoping mast.

Like a bug-eyed fisheye lens, ISIS sees v-e-r-y wide. But that's where the similarity ends. Whereas a typical fisheye lens distorts the image and can only provide limited resolution, video from ISIS is perfectly detailed, edge-to-edge. That's because the video is made from a series of individual cameras stitched into a single, live view—like a high-res video quilt.

"Coverage this sweeping, with detail this fine, requires a very high pixel count," says program manager Dr. John Fortune, of S&T's Infrastructure and Geophysical Division, "ISIS has a resolution capability of 100 megapixels." That's as detailed as 50 full-HDTV movies playing at once, with optical detail to spare. You can zoom in close…and closer…without losing clarity.

The stitching together of several images isn't exactly cutting-edge magic. For years, creative photographers have used low-cost stitching software to create breathtaking high-res images (like that famous image of the National Mall from Inauguration Day 2009). But those are still images, created days or weeks after a scene was shot. ISIS is quilting video—in real time. And, a unique interface allows maintenance of the full field of view, while a focal point of choice can be magnified.

Other tricks—many of which are commercially available—will be provided by a suite of software applications called video analytics. One app can define a sacrosanct "exclusion zone," for which ISIS provides an alert the moment it's breached. Another lets the operator pick a target—a person, a package, or a pickup truck—and the detailed viewing window will tag it and follow it, automatically panning and tilting as needed. Video analytics at high resolution across a 360-degree field of view, coupled with the ability to follow objects against a cluttered background, would provide enhanced situational awareness as an incident unfolds.

In the event that a terrorist attack occurs, forensic investigators can pore over the most recent video, using pan, zoom, and tilt controls to reconstruct who did what and when. Because these controls are virtual, different regions of a crime scene can feasibly be studied by separate investigative teams simultaneously.

Many of the ISIS capabilities were adapted from technology previously developed by MIT's Lincoln Laboratory for military applications. With the help of technology experts from the Department of Energy's Pacific Northwest National Laboratory, Lincoln Laboratory has built the current system with commercial off-the-shelf cameras, computers, image processing boards and software.

ISIS creators already have their eyes on a new and improved second generation model, complete with custom sensors and video boards, longer range cameras, higher resolution, a more efficient video format, and a discreet, chandelier-like frame—no bigger than a basketball. Eventually, the Department plans to develop a version of ISIS that will use infrared cameras to detect events that occur at night.

S&T formed a partnership with the Massachusetts Port Authority (Massport), and in December 2009, began an ISIS pilot at Logan International Airport, allowing potential Homeland Security end users the opportunity to evaluate the technology. Beyond the potential for enhancing security at our nation's airports, if successful, the current testing at Logan could pave the way for the eventual deployment of ISIS to protect other critical venues.

That's a good thing, says S&T's Fortune. "We've seen that terrorists are determined to do us harm, and ISIS is a great example of one way we can improve our security by leveraging our strengths."

(Photo: DHS S&T)

Department of Homeland Security

PLANES, TRAINS AND AUTOMOBILES: TRAFFIC NOISE DISTURBS SLEEP, AFFECTS MORNING PERFORMANCE

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Nighttime noise from nearby road traffic, passing trains and overhead planes disturbs sleep and impairs morning performance, according to a research abstract that was presented Tuesday, June 8, 2010, in San Antonio, Texas, at SLEEP 2010, the 24th annual meeting of the Associated Professional Sleep Societies LLC.

Results indicate that mean reaction time on a morning psychomotor vigilance task slowed significantly by 3.6 ms after exposure to recorded traffic noise during sleep, and the slowing of reaction times was directly and significantly related to increases in both the frequency and sound-pressure level of the nightly noise events. The sound of passing trains caused the highest awakening and arousal probabilities followed by automobile traffic and airplane noise. However, this ranking was not reflected in the measures of morning neurobehavioral performance, as each mode of noise caused a similar level of impairment. Furthermore, exposure to more than one of the three modes of traffic noise did not lead to stronger performance impairments than exposure to only one noise source.

"The study demonstrated that traffic noise may disturb sleep and consequently impede recuperation, as was shown by deterioration of neurobehavioral performance," said lead author Dr. Eva-Maria Elmenhorst, postdoctoral research fellow at the German Aerospace Center Institute of Aerospace Medicine in Cologne, Germany. "The study therefore stresses the importance of sleep hygiene in terms of a quiet environment for healthy, undisturbed sleep."

Elmenhorst noted that nighttime traffic noise may have even stronger effects on the performance of people who are more susceptible to sleep disturbances. Risk groups include children, shift workers, the elderly and people with chronic medical conditions.

The study involved 72 people with an average age of 40 years. Their sleep was monitored by polysomnography for 11 consecutive nights. Recorded traffic noise from airplanes, automobiles and trains was played in the laboratory while they slept. Each mode of traffic noise consisted of eight different noise events played back at five sound pressure levels ranging from 45 to 65 A-weighted decibels for a total of 40 noise events. The study was carefully balanced so that sleeping participants were exposed to one to three modes of traffic noise each night, producing a nightly range of 40 to 120 noise events. The study design also included one control night that was free of traffic noise. Each morning after waking up, participants completed a psychomotor vigilance task, memory search task and unstable tracking task to measure neurobehavioral performance.

The American Academy of Sleep Medicine reports that traffic noise is one cause of "environmental sleep disorder," which involves an environmental disturbance that causes a complaint of insomnia or daytime sleepiness. Other common causes include bright light and temperature extremes.

White noise, which is produced by combining together all the different frequencies of sound, can be used to drown out other sounds and raise your arousal threshold so that your sleep is less disturbed. White noise is produced by box fans and oscillating fans, sound machines, and special applications for computers and smart phones.

In a study published in the February issue of the journal International Archives of Occupational and Environmental Health, Elmenhorst reported that daytime performance was significantly less accurate after nighttime exposure to aircraft noise. In a 2009 study in the journal Aviation, Space and Environmental Medicine, Elmenhorst and colleagues reported on the testing of a simulated "Segmented Continuous Descent Approach," a new noise-reduced approach for aircraft landings.

American Academy of Sleep Medicine

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