Gradient index lenses are described that are integrated within a planar optical structure. A circuit board can include electronic components for which EMI shielding is required. The communication identifier typically facilitates communication over an information space such as the Internet. The light pipe includes a plurality of internal facets that focus light incident on the light pipe toward the light intensity detector. Another embodiment of this invention enables monitoring of the received signal of a system even during operation of the other mode in a multi-mode system. The bedding articles herein are advantageously used in conjunction with a mattress which is inclined to prevent the subject from sliding down the incline under the influence of gravity.