As described previously, cervical cancers are caused by infection with one of the high-risk HPV types. However, since not all people who are infected with HPV will develop cancer, it is likely that other factors also play a role in the development of cervical cancer.
ballast factor (BF) - The ratio of the light output of a fluorescent lamp or lamps operated on a ballast to the light output of the lamp(s) operated on a standard (reference) ballast. Ballast factor depends on both the ballast and the lamp type; a single ballast can have several ballast factors depending on lamp type. compact fluorescent lamp (CFL) - A family of single-ended fluorescent-discharge light sources with small-diameter [16-millimeter (5/8-inch) or less] tubes.
When it comes to lighting in commercial buildings, ballasts are an essential part of the picture. Ballasts limit the amount of current that enters the lights from power supplies. This protects the light bulbs or lighting tubes from the high levels of current that come from the electricity source. Without ballasts, fluorescent lamps in recessed lighting and track lighting would be destroyed by the standard current.