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.
What is frequency band? Frequency bands are groupings of radio frequencies that are used by mobile networks to communicate with mobile phones. The frequency bands that a phone supports determine to a large degree where and on which networks it can be used. For example, T-Mobile USA uses the 1900MHz band for its GSM network, while AT&T uses both 1900MHz and the newer 850MHz frequency bands. Europe and most of the rest of the world use the 900MHz and 1800MHz frequency bands for GSM. So for a device to work properly on T-Mobile USA as well as work in Europe, it would need to support the 1900MHz band and one or both of the 900MHz and 1800MHz bands used in Europe.