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THIS WEEK IN edited by Stella Hurtley and Phil Szuromi CREDITS (TOP TO BOTTOM): SHOWALTER ET AL.; CAO ET AL. Hard Nanowired trace greenhouse gases, CH4 and N2O. As is the case for CO2, CH4 In transistor fabrication, regions with different types of semicon- varied between much more narrow bounds during that time, ductor doping can be created through ion implantation and litho- although N2O varied just as much as it did in the nearly halfmillion years since then. graphic patterning. Yang et al. (p. 1304) now report on the goldThese data will be keys to nanocluster–catalyzed synthesis of understanding how the silicon nanowires that are both highly carbon cycle has operated uniform in diameter with lengths A Single Spiral since the middle of the exceeding 10 micrometers and whose Around Saturn Pleistocene epoch. pattern of doping can be altered anyThe braided strucwhere along the nanowire. Regions of ture of Saturn’s delilight or heavy n-type doping were Hanging On to cate F ring, with its created by changing the amount of Introns wispy interweaving phosphine introduced during growth Evolution has increased strands, has long and were imaged by scanning gate the complexity of organpuzzled astronomers. microscopy. Nanowires with different isms, especially bacteria From sequences of patterns of doping regions were used to and single-celled eukarydetailed images takcreate an address decoder, and at low otes that are contrasted en by the Cassini spacecraft, Charnoz temperatures, the different doping with vertebrates, but it does et al. (p. 1300; see the Perspective by regions defined quantum dots that not necessarily follow that Showalter) show that the F ring is not exhibited Coulomb oscillations. the genes and genomes of so complex and takes the form of a loose organisms that arose early single-arm spiral that wraps around the planet three Springing Back in evolution should be