Science  12 Mar 2004:
Vol. 303, Issue 5664, pp. 1589

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  1. IMAGES: Homing In on the Range

    Boasting 15 years of satellite data, RangeView from the University of Arizona in Tucson lets visitors map vegetation changes across the United States and in parts of Mexico and Canada. Range managers and environmental scientists can use the site to chart the vegetation index—a measure of the type of plants growing in an area and their health—along with variables such as precipitation. Tools allow you to create animations that track changes through time. Above, a rendering of California and Nevada shows May 2003's greenness measures on the left and the deviation from 2002 data on the right.

  2. EXHIBITS: The Man Behind the Mouse

    Slide the cursor across a Web page and click on a highlighted word, and you've used two of Doug Engelbart's creations—the mouse and hyperlinks that direct users from one document to another. Engelbart didn't become a billionaire software mogul. But the California computer scientist's innovations while working at the Stanford Research Institute in the 1960s—which also include word processing, windows, and videoconferencing—transformed the way we interact with computers.

    Learn more about Engelbart's work and ideas for the computer's future at Invisible Revolution, a growing exhibit by Frode Hegland, a Web designer and honorary research fellow at University College London, and his colleague Fleur Klijnsma. Stashed on the site are more than 5 hours of video and audio interviews with the 79-year-old Engelbart, former co-workers, and other computer worthies. For example, Engelbart explains how he got the idea for the mouse from a planimeter, a two-armed drafting instrument for measuring areas, and why he included “only” three buttons. He would have added more if there had been room.

  3. EDUCATION: Getting Entropy Right

    Although dorm-living college students can easily grasp the idea of disorder, using it to explicate the second law of thermodynamics is archaic and misleading, maintains Frank Lambert, a professor emeritus of chemistry at Occidental College in Los Angeles. So Lambert created this collection to help teachers and students understand entropy as a gauge of energy dispersal. The site offers several of his Journal of Chemical Education articles on entropy, a student primer, and pages with deeper explanations for beginning and advanced levels.

  4. DATABASE: Heads or Tails

    The Wnt genes get a developing embryo into shape, helping orchestrate everything from the differentiation of the head and tail ends to the formation of kidney tubules. Faulty Wnt genes can also spur cancer. Keep tabs on the growing gene family at this site from developmental biologist Roel Nusse of Stanford University.

    Tables list all the Wnt genes discovered in model organisms such as Drosophila and in humans—we carry 19. Click on links to gather a gene's DNA and protein sequences or to learn about the proteins it interacts with, which go by names such as Frizzled and Dishevelled. Lab protocols describe techniques such as how to fish out active Wnt proteins, a feat that Nusse and colleagues first achieved last summer. At right, stimulating a frog embryo to make a Wnt protein in the wrong place prompts it to sprout a second head.∼rnusse/wntwindow.html

  5. DATABASE: Biotech Safety Storehouse

    Before it reaches the feed trough or the dinner table, a genetically modified (GM) crop might have to pass scrutiny from the Environmental Protection Agency, the U.S. Department of Agriculture, and the Food and Drug Administration. Helping to inform the debate over the safety of GM organisms is a new federal database listing all engineered food plants that have garnered U.S. government approval. Search the database by crop, type of modification, and developer to find the agencies' health and environmental risk reviews for plants such as soybeans with extra oleic acid (a heart-sparing substance) and corn that rebuffs bugs by producing the natural insecticide Bt toxin.