table sets were computed by using a scaled-solar mixture for the heavy-element distribution. For electron conduction opacities we used a program employing the results by @imii:83, which allows the calculation of the opacity for arbitrary abundances of the most important elements.

The diffusion constants for the gravitational settling of heavy elements are calculated by a routine provided by Thoul , which solves Burgers’ equation for a multicomponent fluid [@diffc]. For the treatment of convection we apply the mixing-length theory [@MWT] with the parameter $\alpha$=1.6. The energy losses from photo-, pair- and plasma-neutrinos are calculated according to @MKI85. Mass loss has been accounted for by using the Reimers’ formula [@reimers] with $\eta$=0.4.

The helium flash induced mixing. {#HeMix}
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The evolutionary and structural properties of low-mass, metal-deficient stars have been described at several instances (see for instance @CC93 and Paper I) and will not be repeated here. We wish to focus our attention on the development of the He-flash induced mixing episode and, primarily, on its dependence on stellar parameters such as the initial helium abundance. The occurrence and the details of the HEFM phenomena have been discussed in detail by @HIF90. Here we emphasize the differences between their results and 