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<jats:p> <jats:bold>PARIS</jats:bold> —Axel Kahn, one of France's leading geneticists, has quit as president of the nation's Biomolecular Engineering Commission, which regulates the use of genetically altered organisms, after a government decision to prohibit cultivation of transgenic corn in France. The government's action came exactly 1 week after it had approved transgenic corn for consumption by humans and animals, and 2 months after the European Commission gave the green light to its commercialization in Europe, largely at the insistence of France. </jats:p>

<jats:p>On 1 June, a set of six CDs, containing the most comprehensive star catalog ever created, will go on sale. They have been put together from data collected between 1989 and 1993 by a European satellite called Hipparcos. The leap in accuracy that the Hipparcos catalog represents will send ripples throughout astrophysics, affecting everything from the age of the universe to the evolution of stars.</jats:p>

<jats:p>After a perfect launch on 8 August 1989, one of the European satellite Hipparcos's onboard motors failed, and the satellite ended up in a highly elliptical rather than a geostationary orbit. Mission controllers managed to save the situation by rewriting software and enlisting the help of additional ground stations, and the satellite survived 4 years, enough to gather a full set of data. However, astronomers still had to endure 3 years of data processing before getting their hands on a single piece of data.</jats:p>

<jats:p>The first known cancer-causing gene is a Jekyll-and-Hyde gene called src, which is benign in normal cells but can turn dangerous when altered by a virus or by mutations. For 20 years, researchers have sought the controls for the Src protein's on-off switch. Two papers in last week's issue of Nature now reveal the crystal structure of the inactive forms of Src and a related protein, showing how this potentially dangerous molecule is restrained in normal cells.</jats:p>

<jats:p> Leg muscles are generally viewed as motors, contracting and relaxing to drive legs up, forward, and down. But new results reported on <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="1113" related-article-type="in-this-issue" vol="275" xlink:href="10.1126/science.275.5303.1113" xlink:type="simple">page 1113</jats:related-article> challenge the long-standing assumption that muscles always do actual work, shortening against resistance to propel an animal forward. By directly monitoring a leg muscle in turkeys running on a treadmill, researchers have now found that the muscle hardly contracts at all, at least when the animals run on level ground. Instead, it shortens slightly before the foot is planted to exert the force needed to keep the tendon attaching the muscle to the heel stretched while the foot is on the ground, thus storing energy for the next stride. As a result, the muscle does very little work. </jats:p>

<jats:p> By now, everyone knows of the giant asteroid that slaughtered the dinosaurs at the end of Cretaceous—but did the extinction really wipe out thousands of terrestrial animals? Not according to a new study of the genes in modern birds. The molecular study on <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="1109" related-article-type="in-this-issue" vol="275" xlink:href="10.1126/science.275.5303.1109" xlink:type="simple">page 1109</jats:related-article> of this week's issue of <jats:italic>Science</jats:italic> suggests that many bird lineages (including those of penguins, parrots, and chickens) arose before the extinction and flew through it unscathed. </jats:p>

<jats:p>Using a scanning tunneling microscope (STM)—the probe with an atom-fine tip—a pair of European researchers made the accidental discovery that if you squeeze a soccer-ball-shaped fullerene molecule of 60 carbon atoms, its electrical resistance changes. The pair then constructed a circuit, incorporating the STM, which uses a single “buckyball” as an electromechanical amplifier.</jats:p>

<jats:p>Electron microscopes suffer from optical aberrations much like the ones that add a fringe of color to the images seen with a magnifying glass. Now a fix is in sight: a corrective “electron mirror” that precisely counteracts the aberrations introduced by the electron lens. The mirror could increase the resolution of some high-powered electron microscopes by a factor of 5 or more.</jats:p>

<jats:p> <jats:bold>SAN DIEGO</jats:bold> —Minnesota Fats has some mathematical competition. With a little help from a computer, a mathematician has demonstrated some amazing three-dimensional shots for a cue ball bouncing around inside three equal-sided, or Platonic, solids—the eight-sided octahedron, the 12-sided dodecahedron, and the 20-sided icosahedron. Each shot hits each side of the pertinent solid and returns to its exact starting point and direction of travel. </jats:p>