Alain Parkinson Luminarium at Budapest's Sziget Music Festival

Alain Parkinson is a British artist who designed an inflatable 'Luminarium' to serve as a chillout space during the Budapest Sziget Music Festival. The festival is held on an island on the Danube river running through the city, and has been running since 1993. In 2006 attendance neared 400,000, and this year it seems that it will reach that capacity again.

Circadian math: 1 plus 1 doesn't always equal 2

Researchers have found that the circadian system may be able to distinguish between lights of different colors. Credit: Rensselaer/Lighting Research Center

Like a wristwatch that needs to be wound daily for accurate time-telling, the human circadian system — the biological cycles that repeat approximately every 24 hours — requires daily light exposure to the eye's retina to remain synchronized with the solar day. In a new study published in the June issue of Neuroscience Letters, researchers have demonstrated that when it comes to the circadian system, not all light exposure is created equal.

The findings have profound implications for exploring how lighting can be used to adjust our bodies' clocks, and they could redefine the way lighting is manufactured, according to Mariana Figueiro, lead author of the paper and assistant professor in the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute.

Short-wavelength light, including natural light from the blue sky, is highly effective at stimulating the circadian system. Exposure to other wavelengths — and thus colors — of light may necessitate longer exposure times or require higher exposure levels to be as effective at "winding the watch."

In some instances, exposure to multiple wavelengths (colors) of light simultaneously can result in less total stimulation to the circadian system than would result if either color were viewed separately, a phenomenon known as "spectral opponency." The LRC scientists have shown that the circadian system shares neurons in the retina — which exhibit spectral opponency and form the foundation for our perception of color — with the visual system. Thus, in principle, the circadian system may be able to distinguish between lights of different colors.

More than meets the eye

To demonstrate that the circadian system exhibited spectral opponency formed in the retina, the researchers exposed 10 subjects to three experimental conditions: one unit of blue light to the left eye plus one unit of green light to the right eye; one unit of blue light to the right eye plus one unit of green light to the left eye; and half a unit of blue light plus half a unit of green light to both eyes and then measured each individual's melatonin levels, a natural indicator of the circadian clock.

"The first two conditions — exposure to a single color in each eye — did not result in a significant difference in melatonin suppression, while the third condition — exposure to both colors in both eyes — resulted in significantly less melatonin suppression," said Figueiro. "Even though the amount of light at the eye was the same in all three conditions, when the two colors of light were combined in the same eye, the response of the system was reduced due to spectral opponent mechanisms formed in the retina."

This indicates that spectral opponency is a fundamental characteristic of how the human retina converts light into neural signals in the human circadian system, according to Figueiro.

The findings also verify the accuracy of a new quantification system LRC researchers developed in 2006 to calculate the "circadian efficacy" of different light sources. Called the model of human circadian phototransduction,
the tool correctly predicted the circadian system response demonstrated under each of the three experimental conditions.

The model appears to correctly predict the circadian response to any light source, and can be used as the foundation for a new system of circadian photometry, much like the current system of photometry based on human vision.

Quantification of light as a stimulus for the circadian system provide new scientific insights into how the human body processes light for the circadian system, according to Figueiro.

Nocturnal melatonin, a hormone produced at night and under conditions of darkness, is used as a marker for the circadian clock. Scientific evidence suggests that disruption of the circadian system — and thus the melatonin cycle — may result in increased malignant tumor growth, as well as poor sleep quality, lack of alertness, seasonal depression, and immune deficiencies.

Now that the model can predict circadian efficacy for any light source, Figueiro and her research partners have begun studying the way time of night affects the potency of light exposure. Once complete, the comprehensive model will allow manufacturers to develop light sources that most effectively stimulate and, importantly, do not stimulate the circadian system.

Source: Rensselaer Polytechnic Institute
http://www.physorg.com/news132055021.html
Published: 10:57 EST, June 07, 2008

Why you need green exercise

It's no wonder that fitness resolutions tend to fizzle in February. Chicagoans vow to get in shape at the worst possible time of the year, just when miserable weather forces us indoors.

We do have health clubs. And winter kicks off the mall-walking season. ("Meet in the food court!"). But some suspect we need more than just physical exercise to stay healthy. We need the emotional healing benefits of green exercise.

Also known as eco-therapy, green exercise simply means doing something, almost anything, outside. You won't necessarily burn more calories in nature's green gym.

But you can get substantial mental health benefits—reduced stress, depression and anger and enhanced mood and self-esteem—simply by seeking out the natural world, according to growing evidence from researchers in the U.S., Scandinavia and Britain.

In fact, in color therapy, green balances the nervous system and is believed to have a calming, soothing effect. It stimulates growth, and exposure to it is said to help those those suffering from depression, anxiety and nervousness.

Reconnecting with the environment could be as simple as viewing nature in a picture or through a window. Studies have shown that prisoners and hospital patients reported better health when living in rooms that face farmland and trees rather than brick walls.

Scenery also made a difference for another group of shut-ins: treadmill runners, according to researchers at the University of Essex in Britain. They found that runners who zoned out on idyllic rural views during a 20-minute run had the most substantial drop in blood pressure and the most improved psychological outcomes. The runners forced to look at gritty city environments, or "urban unpleasant" views, fared the worst.

Even those who had "no view" on the treadmill reported better outcomes than the ones looking at the run-down urban scenes.

Or green exercise could mean sitting in a park, biking to work, walking, fishing or digging in the dirt. The stress-reduction benefits of healing gardens in hospitals (which we could now call “green care”) date to the Middle Ages. And some say our modern hospitals, which focus on treating disease, have abandoned the healing properties that the connection to nature can bring.

Even mall walking, which can feel more fatiguing than an hour run, doesn't boost self-esteem as much as strolling through the woods for those diagnosed with mental health problems, according to Jules Pretty, a professor of environment and society at the University of Essex, a hotbed of green-exercise research.

"Clearly nature delivers important health benefits if we reorganize lifestyles and behaviors," Pretty recently wrote in a commentary published in New Scientist.

The biggest challenge, Pretty said, is redesigning cities to get people to walk more during normal working days.

"Fifty years ago, an average adult ran the equivalent of a marathon a week more than an average adult does today—and that was not running, just walking, cycling, being more active in the home," said Pretty, author of "The Earth Only Endures: Reconnecting With Nature and Our Place in It" (Earthscan, $29.95). "No wonder obesity is such a problem."

Locally, groups are working on ways to make green exercise easy and inevitable. Chicago's upcoming daylong Modeshift Conference 2008, to be held Feb. 28 at the Metcalf Federal Building, 77 W. Jackson Blvd., focuses on transforming a community’s transportation habits by teaching participants how to convert car trips to walking, biking and public transit.

This laudable goal is important for both ethical and economic reasons. But Pretty and other green-exercise advocates argue that there is another very good reason for conservation: the psychological and healing benefits of nature.

"Nature and living things, it seems, tend to make most people feel good," Pretty said. "The idea that the quality of nature in people's home neighborhood affects their mental health is not a new one, but it has not greatly affected the planning of our urban and rural environments, nor of public health priorities.

"Establishing emotional connections with the environment also inspires people to think about conservation and climate change," Pretty explained. "That, in turn, is likely to encourage environmentally friendly behaviors, a virtuous cycle of benefit to the environment."

Register for Modeshift, which is presented by the U.S. Environmental Protection Agency and the Chicagoland Bicycle Federation, at biketraffic.org/modeshift.
http://featuresblogs.chicagotribune.com/features_julieshealthclub/2008/02/the-best-brain.html