A number of factors can lead companies to close stores. One is mergers and acquisitions activity. As organizations join forces under a single umbrella, locations that once competed for sales can become redundant, leading to store closings.
There are 3 types of ultraviolet (UV) rays: 1  Ultraviolet A rays (UVA) make up most of the sun's natural light. They can penetrate deep into the skin, causing wrinkles and premature aging of the skin.  Ultraviolet B rays (UVB) are the main cause of sunburn. They are nearly 1,000 times stronger than UVA rays.
UVB ranges from 290 to 320 nm. With even shorter rays, most UVC is absorbed by the ozone layer and does not reach the earth. Both UVA and UVB, however, penetrate the atmosphere and play an important role in conditions such as premature skin aging, eye damage (including cataracts), and skin cancers.