In an article just published on Monthly Notices of the Royal Astronomical Society we presented the first general-relativistic simulations with microphysics and neutrinos to explore the dynamics of merging binary neutron star systems with large mass ratios. We found that the lower mass neutron star in these binaries is tidally disrupted by the primary neutron star shortly prior to merger. The accretion of the tidal debris can cause the more massive neutron star to collapse and form a black hole surrounded by a large accretion disk. Our simulations showed that, contrary to common expectations, neutron star mergers with prompt black hole formation can be accompanied by bright electromagnetic counterparts. Our work is featured in press releases by Pittsburgh Supercomputing Center and the Pennsylvania State University.