Breakthroughs in robot locomotion don't come often. One has just rolled out of Carnegie Mellon University, a hotbed of robot innovation. The new bot scoots about on a rubber ball the size of a cantaloupe -- a design that makes CMU's "ballbot" highly maneuverable.

The robot, which stands about five feet tall, relies on three gyroscopes and a high center of gravity to stay upright. Its computer brain interprets readings from the gyros, then balances and steers by means of small electric rollers atop the ball. The rollers can propel it in any direction, and also keep the ballbot's lighter lower half centered under its heavier upper half, explains Ralph Hollis, a research professor at CMU's Robotics Institute.

The top-heavy design has advantages over conventional robots. For one, its base is much smaller than those relying on legs, wheels, or tractors, so the 95-lb. unit can get into tighter spaces and can rotate in place. That's important, as researchers believe such automatons will one day work in homes and offices. The ballbot has one flaw, though. So far, it works only on flat surfaces. Hollis says his team's next test is to attach mechanical arms to the unit to see how they affect its movement. Scientists have predicted that global warming might flip a planetwide switch that controls ocean currents, triggering drastic climate shifts. In fact, this could happen over the next century, sooner than originally thought.

The switch involves the flow of cold, salty water in the North Atlantic and Arctic Oceans. As these relatively heavy waters sink, they drive a massive deep-ocean current that flows south and then east. To replace all that sinking water, warm water is drawn up from the tropics. But if the Arctic waters grow warmer and less salty, eventually they will stop sinking, and this thermal conveyor belt will halt. One likely effect: Winters in Europe and parts of Canada and the U.S. will get colder.

This dramatic change was thought to be centuries off. But in an upcoming paper in Science researchers from the Marine Biological Laboratory in Woods Hole, Mass., and elsewhere calculate that rising precipitation and melting ice are flushing enough fresh water into the Arctic Ocean that the switch may be flipped by the year 2100. Clothes are about to get a whole lot brighter. With Philips' (PHG

) new Lumalive system, swaths of fabric can be turned into glowing, multicolored panels able to display characters or simple animations. The key is a web of tiny light-emitting diodes (LEDs) integrated into a layer of the fabric. Powered by a small battery pack and connected by superfine wires, Lumalive materials are so light they drape just like normal fabric. Expect to see larger grids of the illuminated textiles replacing regular fabrics in everything from upholstery to draperies to wall coverings. Although Philips isn't yet talking about price, commercial production is slated for 2007. And with it, inevitably, comes the dawn of animated jacket-back ads. -- Purdue University researchers are tinkering with the DNA of a hybrid poplar tree in hopes of creating a new source of biofuel. Their vision: a tree that can shoot up 15 feet in a year, and whose wood, when fermented, will yield nearly twice as much energy per bushel as corn kernels used to make ethanol today. Grown on fallow land, the sterile trees wouldn't compete with food crops and shouldn't accidentally trade genes with any other plants. The researchers' first focus is to lower the amount of a compound called lignin in the poplar's cells. Lignin gives trees strength but gums up the ethanol-making process.

-- Excessive consumption of carbohydrates, which convert to fat in the body, is a leading cause of obesity. By suppressing the protein that controls this carbs-to-fat process, researchers have shown that they can prevent obesity and reduce appetite -- at least in mice. Working with mice engineered to become obese, the scientists suppressed the gene that produces the suspect protein. The mice with the disabled gene remained thin, even though they ate a very high carbohydrate diet. They also consumed less food than mice that had the gene intact. And they were less likely to have symptoms of diabetes. University of Texas researcher Kosaku Uyeda says the protein, called ChREBP, could be a target for anti-obesity drugs. The research was funded by the National Institutes of Health and the Veteran's Administration.