Electrical resistivity and conductivity results in the important concept of "quasineutrality", which says the density of negative charges is approximately equal to the density of positive charges over large volumes of the plasma ("n" = <Z>"n"), but on the scale of the Debye length there can be charge imbalance. In the special case that "double layers" are formed, the charge separation can extend some tens of Debye lengths. The magnitude of the potentials and electric fields must be determined by means other than simply finding the net charge density. A common example is to assume that the electrons satisfy the Boltzmann relation: Differentiating this
Negative and positive rights both "positive" and "negative" duties, but it seems that rights that do not involve forced labor can be phrased positively or negatively at will. The distinction between positive and negative may not be very useful, or justified, as rights requiring the provision of labor can be rephrased from "right to education" or "right to health care" to "right to take surplus money to pay teachers" or "right to take surplus money to pay doctors". Negative and positive rights Negative and positive rights are rights that oblige either action ("positive rights") or inaction ("negative rights"). These obligations may be of either