A mobile receiver apparatus is provided where its antenna directivity is controllably determined for improving the response to a desired signal as it moves and its surrounding geographical features and thus its environment for signal reception are varied. A system may be configured to identify an appointment in a calendar application, identify a geographic location of the appointment, and identify, before the appointment time, a geographic location of a first participant of the appointment. A first electromagnet has opposing first and second pole faces, the first pole face coupled to the second face of the first layer of soft-matrix magnetorheological material. Overall, the ISL’s of the prior art are subject to weak intersubband population inversion. A medium priority value is derived from the second water level when the first water level is equal to zero.