My current research concerns the effects of higher shell admixtures on properties of nuclei. Topics which are addressed when realistic interactions are used include "self weakening of the tensor interaction in a nucleus due to higher shell admixtures" and the effects of intruder states in 8Be and 8B on reactions of importance for the production of elements in the stars, e.g. p + 7Be -> 8B + [[gamma]] (note that 8B is the main producer of high energy neutrinos in the sun). In order to better understand nuclear collectivity we also use the schematic quadrupole-quadrupole Q*Q interaction. We show a new way to get Elliott's SU(3) results without invoking a momentum dependent part to the quadrupole operator. In this new formulation SU(3) symmetry is restored by including the particle-core interaction.