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.
Polycarbonate plastic film comes in a rigid format that makes it easy install on the greenhouseâs frame. Some polycarbonate is corrugated, while other products have two smooth outer layers that encase an inner corrugated structure, much like that of a cardboard box. Polycarbonate material allows up to 91 percent of the light into the greenhouse.