Anisotropic Outflows and Enrichment of the Intergalactic Medium
  We have developed an analytical model for the evolution of anisotropic galactic outflows. These outflows follow the path of least resistance, and thus travel preferentially into low-density regions, away from cosmological structures where galaxies form. We show that anisotropic outflows can significantly enrich low-density systems, while reducing the enrichment of overdense regions. 
Matthew M. Pieri, Hugo Martel, Cedric Grenon