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 tends to cause damage in more superficial epidermal layers. UVB is the middle-range of UV with wavelengths between 290-320 nm. It responsible for burning, tanning, acceleration of skin aging and plays a very key role in the development of skin cancer.The intensity of UVB varies by season, location and time of day.VB tends to cause damage in more superficial epidermal layers. UVB is the middle-range of UV with wavelengths between 290-320 nm. It responsible for burning, tanning, acceleration of skin aging and plays a very key role in the development of skin cancer.