There were large problems with the newly defined groups, since they were very heterogeneously defined. If the surface is wetted heterogeneously, the droplet is in Cassie-Baxter state. Unfortunately, nickel isotopes appear to have been heterogeneously distributed in the early solar system. Typically these conversions are catalyzed heterogeneously by titanium trichloride which are activated by aluminium alkyls. Whale falls are distributed heterogeneously throughout space and time, with a concentration along migration routes.