Ultrasound may show gallstones, thickening of the gallbladder wall, extra fluid, and other signs of cholecystitis. This test also allows doctors to check the size and shape of your gallbladder. You could also have a gallbladder scan, a nuclear scanning test that checks how well your gallbladder is working.
For high speed algorithmic trading, see high-frequency trading. HF's position in the electromagnetic spectrum. High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 MHz.It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters (ten to one hundred metres).Frequencies immediately below HF are denoted medium frequency (MF), while the next band of higher frequencies is known as the very high frequency (VHF) band.requencies immediately below HF are denoted medium frequency (MF), while the next band of higher frequencies is known as the very high frequency (VHF) band.
The utility frequency, line frequency or mains frequency is the nominal frequency of the oscillations of alternating current in an electric power grid transmitted from a power station to the end-user. In large parts of the world this is 50 Hz, although in the Americas and parts of Asia it is typically 60 Hz. Current usage by country or region is given in the list of mains power around the world. During the development of commercial electric power systems in the late 19th and early 20th centuries