We propose a new solution to the cosmological monopole problem in which domain walls sweep away the magnetic monopoles and subsequently decay. The solution does not require extensive finetuning or model building; it works for the prototype SUs5d grand unification model. More generally, it shows that defect interactions can lead to “defect erasure” in phase transitions and that this can be relev...

In this paper, we consider the filter step of the spatial join problem, for the case where neither of the inputs are indexed. We present a new algorithm, Scalable Sweeping-Based Spatial Join (SSSJ), that achieves both efficiency on real-life data and robustness against highly skewed and worst-case data sets. The algorithm combines a method with theoretically optimal bounds on I/O transfers base...

The residual buildup and treatment of dissolved contaminants in low permeable zones (LPZs) is a particularly challenging issue for injection-based remedial treatments. Our objective was to improve the sweeping efficiency of permanganate into LPZs to treat dissolved-phase TCE. This was accomplished by conducting transport experiments that quantified the ability of xanthan-MnO4(-) solutions to pe...