A light fixture is disclosed which includes junction box, an annular mounting plate, a canopy, a collar loop, a collar nut and a light assembly which includes a length of electric cord. According to various aspects, optimal rank selection and CQI computation for an optimal rank can be performed in conjunction with a non-linear receiver, such as a maximum likelihood MMSE receiver, a non-linear receiver with a list-sphere decoder, and the like. Respective financial account information can be received from each of a plurality of mobile devices via near field communication. The processor can be configured to select a frequency for the drive current, and the amount of drive current at increased frequencies may exceed a safety threshold for the drive current at lower frequencies. The machine automatically couples zipper sliders with zipper bags in large amounts while taking little time, thereby significantly enhancing production efficiency.