Earth analysis methods, subsurface feature detection methods, earth analysis devices, and articles of manufacture are described. The first conductive layer comprises a first and a second conductive strip, separated, mutually parallel, each in one end connected to a first output and in another end connected to a second output. The rescuer merely needs to press a start button to initiate operation of the AED and begin CPR and defibrillation instruction. Also provided herein are polynucleotides encoding the polypeptides, genetically modified microbes that include polynucleotides encoding one or more subunits of the multimeric polypeptide, and methods for making and using the polypeptides. The preloaded spring may be positioned on one side of the printed circuit board and the heat sink may be positioned on the opposite side.