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.
The Best Materials to Cover your Greenhouse. 1  Glass: The traditional greenhouse covering, glass is the preferred material for permanence. 2  Film Plastic: Film plastic is one sixth to one tenth of the cost per square foot of a glass covered structure.
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.