The parathyroids produce a hormone called parathyroid hormone (PTH). PTHPTH-parathyroid hormone raises the blood calcium level by: 1  breaking down the bone (where most of the body's calcium is stored) and causing calcium release. 2  increasing the body's ability to absorb calcium from food.THPTH-parathyroid hormone raises the blood calcium level by: 1  breaking down the bone (where most of the body's calcium is stored) and causing calcium release. 2  increasing the body's ability to absorb calcium from food.
DN = Diameter Nominal. The term Diameter Nominal refers to the internal diameter of a pipe. Together with the nominal pressure rating and the materials class, all dimensions of a piping line, e. g. flange dimensions, are defined by indicating the nominal diameter. Steel is often not specified, but assumed as material.
Tell R that a variable is nominal by making it a factor. The factor stores the nominal values as a vector of integers in the range [ 1... k ] (where k is the number of unique values in the nominal variable), and an internal vector of character strings (the original values) mapped to these integers.