Corrections and Clarifications
In the report "Secondary and tertiary structural effects on protein NMR chemical shifts: An ab initio approach" by Angel C. de Dios et al. (4 June, p. 1491), the abscissas of figure 1, B and D, on page 1492 were inadvertently transposed during production. Figure 1B's abscissa should have read, "Cutoff radius (Å)," and figure 1D's abscissa should have read, "Experiment (ppm)."