Best fits (top panel) and their residuals (bottom panel) for the metal-poor star CS29528-028. The squares are the abundances from Aoki et al. (2007), and the circles are from Allen et al. (2012). Only an upper limit was derived for nitrogen. When two measurements were available for one element, the most recent one (Allen et al. 2012) was selected to calculate χ² and used to plot the residuals. The four patterns show the best fits and their χ² value for four models (cf. text for details). All models were considered after beta decay.