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.
1 The most basic greenhouse-type structure is a cold frame, a low box or hoop-like structure designed to protect plants in the ground without any additional heat or light sources. 2  A basic cold frame starts at $30-$100, but larger and more durable models can cost $100-$600. Cooling can be provided by a simple fan ($10-$50 or more) or by covering the roof with shade cloth or roller shades (starting around $25-$100, but going as high as $1,000 or more). 2  A basic potting bench starts around $50-$250, but can cost $1,200 or more. 3  For details, see How Much Does a Potting Bench Cost.