Deep impact. NASA's Opportunity rover has delivered yet another surprise. This rock, named Marquette Island, is unlike any other the six-wheeled robot has found. Its coarse-grained composition shows it originated not on the planet's su**ce but within its interior. Sometime in the past a massive object--probably a small asteroid--slammed through the Martian su**ce, ejecting rocks from inside the crust. After being flung high into the sky, the basketball-sized rock landed on Meridiani Planum, conveniently where Opportunity has been exploring for the past 6 years. "It is from deep in the crust and someplace far away on Mars," says chief mission scientist Steve Squyres. "Though exactly how deep and how far we can't yet estimate."
Glow parade. Researchers have trained bacteria to put on a light show. Genetically modified Escherichia coli were equipped with a communication system allowing them to sense each other's presence using secreted small molecules. When this system was linked to a genetic clock inside the cell, the bacteria were able to synchronize the production of a green fluorescent protein across the colony (see video). When the cells reached a critical density, this resulted in bursts of fluorescence (shown left). The work, reported 21 January in Nature, may enable researchers to develop cell implants capable of administering therapeutics at appropriate times.
Tough guy. This gastropod's shell has even the best metal armor beat. It's the kind of protection the scaly-foot snail (Crysomallon squamiferum) needs as it fights enormous water pressure and the vice-like grip of crabs on the deep sea bottom. The shell's unique three-layered structure--an iron-sulfide outer shell, a thick organic middle, and an inner calcified layer--dissipates stress so well, researchers report online 19 January in the Proceedings of the National Academy of Sciences, that copying it should lead to tougher personal-protection vests and bomb-proof vehicles.
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发表于 2010-1-26 21:47
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