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The Cutting Edge: Computing / Technology / Innovation : Chaos Allows Data to Be Heard

August 03, 1994|KATHLEEN WIEGNER

To many people, the sounds of chaos might mean the music of a heavy metal group. But scientists at the University of Illinois at Urbana-Champaign have given the mathematical theory of chaos some music of its own. Researchers at the National Center for Supercomputing Applications have created a computer interface that not only allows users to see chaotic interactions, but to hear them as well.

The interface presents a digital representation of a ball that can be moved across a textured plane. Changing the peaks and valleys on the plane or moving the ball to a different area of the plane produces different sounds. The interface can produce sounds using almost any numerical data. With the interface, chaos becomes a musical instrument--just as musicians use the keyboard to explore the sounds of the piano.

Scientists are excited about this sonification of data because it gives them another way other than visually to interpret complex data. What if storm patterns were not only visible on a screen, but also became louder as winds increased?

Musical composers are also intrigued: Insook Choi, a UIUC research assistant, has composed a musical piece using the sounds of chaos. Her composition, "anti-Odysseus, the irreversibility of time," premiered at Expo 93 in Taejon and Seoul, Korea.

Switching Off Mercury: Steam irons that turn off automatically and the lights that turn on when you open the trunk of your automobile have one thing in common: a mercury-based switch. Mercury switches turn up in thousands of modern conveniences, from computer screens to thermostats to street lights. Because mercury flows, it is used in switches that work based on the position of the objects. The problem is, once in the environment, mercury changes into toxic compounds. California, Florida and Minnesota have already banned new products containing mercury, and New Jersey prohibits the disposal of such products.

Coming up with an alternative to mercury wasn't easy, as scientists at Virginia Tech found when a Virginia businessman asked them to develop a non-mercuric switch. The substance would have to work with AC power and preferably DC as well. It had to be non-hazardous to the environment and had to work in subfreezing temperatures.

The answer came in the form of a gallium-based alloy that is actually more conductive than mercury, meaning switches can be made smaller and still carry electricity. The initial U.S. patent on the NonMerc switch will be issued this fall. The technology has been licensed to NonMerc, a new company in Manassas, Va., created to commercialize the switch.

From Feast to Famine: Legumes such as cowpeas, black-eyed peas, chickpeas and mung beans are important sources of protein in developing nations in Africa, Asia and South America. Unfortunately, their seeds are also an important food source for insect larvae, particularly weevils that can virtually wipe out a seed granary in a few months. The quest for pest-resistant seeds is fueled in part by a lack of insecticides in much of the Western world. About five years ago, a team of researchers led by a biologist at University of California, San Diego, began looking for a way to genetically engineer insect-resistant seeds for these important legumes. The researchers discovered that certain weevils could be stunted when fed a diet that inhibited amylase, a protein needed to digest starch.

The gene responsible for an amylase inhibitor protein was found in the common kidney bean. By transferring that gene from the kidney bean into a legume species, seeds were produced that are indigestible to weevils and thus starve the larvae. Maarten Chrispeels, the biologist who led the team, believes this is the first time seeds themselves have been made resistant to the insects.

Pinwheels for the Mind: A videotape of concentric circles somewhat akin to a child's pinwheel is helping researchers at Stanford University push imaging of the human brain to a resolution almost 50 times greater than previously accomplished. By tracking blood flow, magnetic resonance imaging machines have allowed researchers to see brain activity on the level of millions of neurons. But previous attempts to see it on the level of a few hundred thousand or fewer have been frustrated by surges of blood flowing through vessels to reach specific neurons.

To prevent such surges, researchers designed a videotape of concentric circles of white alternating with a checkerboard pattern that moves in and out across the field of vision in a regular pattern. The neurons responsible for monitoring different locations in the field respond only when the flickering checkerboard passes into the range they monitor.

Because only half the visual field is stimulated at a given time, the blood flow to the area is roughly constant. The work has the potential to aid in diagnosis and treatment of temporary or permanent damage from strokes or accidents, as well as developmental problems.

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