In DSM, nicotine dependence is included under the general definition of substance dependence.  The essential feature of Substance Dependence is a cluster of cognitive, behavioral, and physiologic symptoms indicating that the individual continues use of the substance despite significant substance-related problems.
Greenhouse Covering. Whether you're replacing existing greenhouse coverings or building a greenhouse you're sure to find the best greenhouse covering at FarmTek. Greenhouse glazing is the material that covers the greenhouse frame and the most widely used materials are polycarbonate and poly film.
Inside a greenhouse. A greenhouse (also called a glasshouse or hothouse) is a building where plants such as flowers and vegetables are grown. It usually has a glass or translucent plastic roof. Many greenhouses also have glass or plastic walls. Greenhouses warm up during the day via penetration of the sun's rays which heat the plants, soil and structure. This heat is given up gradually throughout the night.