Calcium nitrate salt" 5Ca(NO).NHNO·10HO. This is called calcium ammonium nitrate. Formulations lacking ammonia are also known: Ca(NO)·4HO (11.9-0-0 + 16.9 Ca) and the water-free 17-0-0 + 23.6 Ca. A liquid formulation (9-0-0 + 11 Ca) is also offered. An anhydrous, air-stable derivative is the urea complex Ca(NO)·4[OC(NH)], which has been sold as Cal-Urea. Calcium nitrate is also used to control certain plant diseases. For example, dilute calcium nitrate (and calcium chloride) sprays are used to control bitter pit and cork spot in apple trees. Calcium nitrate is used in waste water pre-conditioning for odour emission prevention. The waste water pre-conditioning is based
Symbol table global scope, whether it is imported, and what namespace it belongs to. Some programming languages allow the symbol table to be manipulated at run-time, so that symbols can be added at any time. Racket is an example of such a language. Both the LISP and the Scheme programming languages allow arbitrary, generic properties to be associated with each symbol. The Prolog programming language is essentially a symbol-table manipulation language; symbols are called "atoms", and the relationships between symbols can be reasoned over. Similarly, OpenCog provides a dynamic symbol table, called the "atomspace", which is used for knowledge representation. Symbol table