Using rational homology circles to construct rational homology balls

Motivated by Akbulut-Larson's construction of Brieskorn spheres bounding rational homology 4-balls, we explore plumbed 3-manifolds that bound circles and use them to construct infinite families 3-spheres 4-balls. Some these are new examples integer but do not In particular, find torus bundles over the circle circles, provide a simple method for constructing more general show that, example, $-1$-surgery along any unknotting number one knot $K$ with positive crossing can be switched unknot bounds 4-ball.