Frequency combs are light sources with a spectrum that comprises a series of sharp, equally spaced lines. The frequencies of these lines are known to a very high degree of accuracy, which makes ...

The conflict between Israel and the Palestinian people is one of the longest-running and most violent disputes in the world. Its origins go back more than a century. There have been a series of ...

Anybody can develop high frequency hearing loss, but it becomes more common with age. Exposure to loud sounds or high frequency sounds are common causes of ear damage in younger people.