“…[Z], Z ⊂ Y, codim Z = 2 introduced in (6.2) is trivial in this case. The conclusion of the above-mentioned Theorems 6.5 and 6.24 is that for a uniruled threefold with CH 0 = Z, all the interesting (and birationally invariant) phenomena concerning codimension 2 cycles, namely the kernel of the AbelJacobi map (Mumford [71]), the Griffiths group (Griffiths [48]) and the group Z 4 (X) versus degree 3 unramified cohomology with torsion coefficients (Soulé and Voisin [93], Colliot-Thélène and Voisin [24]) are trivial. In the rationally connected case, the only interesting cohomological or Chow-theoretic invariant could be the Artin-Mumford invariant (or degree 2 unramified cohomology with torsion coefficients; see [23]), which is also equal to the Brauer group since Stated in words, this question asks for the existence of a universal codimension 2 cycle on J(Y ) × Y .…”