Known for hot temperatures, Southern California and the rest of the Southwest United States are undergoing a cold snap that has set records in many areas throughout the region.
Periodogram is the spectrum of a set of time signal usually obtained by fast Fourier transform (FFT). It usually shows frequency as x-axis, and magnit... This page may be out of date.
An aortogram is an image of the aorta, the largest artery in the body, acquired by injecting a radiopaque substance into a patient and using medical imaging equipment to snap a series of pictures.