**4. Recent Advances Based on Shell-Model Analysis**

The shell-model approach described in Section 3 has formed the backbone of this field of study over the last two decades. The strength of the shell-model prescription is the simultaneous inclusion of the multipole and monopole effects, since the relative scale of the contributions of the four components described in Section 3 changes from case to case. Examples of this are the *T* = 1 and *T* = 2 mirror nuclei with *A* = 48 [8,54], one of which is a case study in Section 2.3. Each of these pairs of mirror nuclei, which lie in the exact centre of the *f* <sup>7</sup> 2 shell, would also be "cross conjugate" nuclei in the assumption of a single isolated *f* <sup>7</sup> 2 shell. In this extreme assumption, which is not bad for the *f* <sup>7</sup> 2 shell, all multipole MED would be zero since the number of protons in one nucleus is the same as the number of proton holes in the mirror partner. In the case of the *T* = 1, *A* = 48 mirrors [54] this appears to be the case, and the experimental MED is largely accounted for by the monopole *VCr* term. This nicely demonstrates the power of the approach in accounting for a range of phenomena.

In this Section, some of the latest developments in this field, specifically relating to shell-model analysis, are discussed, focussing in particular on the results from the case studies presented in Section 2.
