Methods for detecting the presence or amount of Johnsongrass or Johnsongrass hybrid genetic material in a biological sample, preferably the detection of the presence or amount of Johnsongrass or Johnsongrass hybrid seed in a seed sample, are disclosed. In a cowl structure for a vehicle which includes a front cowl for covering a front portion of a vehicle body, a radiator is positioned in front of the cylinder heads of the engine. Such information is used to build a spatial index of specific physical locations for a geocoded result set. The signal may, for example, stop the supply of electric power to the power supply couple. Before selecting the channel, the method detects a channel which another radio network is using and a channel having high noise. Using the natural tendency of vacuum adherence devices to adhere to changing surface contours, the crawler vehicle can adhere itself to airfoil-shaped structures in a way that allows the crawler vehicle to easily translate along an airfoil-shaped body while accommodating extreme variations along the surface of the airfoil-shaped body.