Retin-A (tretinoin) is a form of vitamin A that helps the skin renew itself. The Retin-A and Avita brands of tretinoin are used to treat acne. The Renova brand of tretinoin is used to reduce the appearance of fine wrinkles and mottled skin discoloration, and to make rough facial skin feel smoother. Retin-A may also be used for purposes not listed in this medication guide.
Waste Stream. The total flow of solid waste from homes, businesses, institutions, and manufacturing plants that is recycled, burned, or disposed of in landfills, or segments thereof such as the residential waste stream or the recyclable waste stream..
A perennial stream or perennial river is a stream or river (channel) that has continuous flow in parts of its stream bed all year round during years of normal rainfall.he boundaries between perennial, intermittent, and ephemeral channels are indefinite, and subject to a variety of identification methods adopted by local governments, academics, and others with a need to classify stream-flow permanence.