Barium- and strontium-to-iron ratios as a function of [Fe/H] in Sculptor seen in orange, compared to the Milky Way halo stars in grey. The open circles correspond to HE 1219-0312, HD 140283, HD 122563, HD 88609, and HE 2327-5642, five Milky Way halo stars for which the odd-A fraction could be estimated. The ultra−faint dwarf spheroidal galaxies are displayed with black symbols. Ursa Major II is identified with triangles, Coma Berenices with stars, Leo IV with squares, Hercules with pointing down triangles, Segue I with pointing right triangles, and Boötes with diamonds. The full references are given in Sect. 5.1.