### density:

Low density
* means areas which are largely made up of parcels greater than one acre.
* sprawling urban areas reduce the life supporting capacity of rural land.

Mass density
* catalyst for nuclear fusion.
* is represented in grey-levels.

Nutrient density
* is greater in less mature forage than in older plant material.
* is the amount of nutrient per energy unit
  - nutrient to calorie ratio of the food supply
* refers to the concentration of nutrients in the diet
  - quantity of essential nutrients in a given volume of food

Optical density
* is density
  - directly proportional to the number of cells
* logarithmic scale, so small increases are more significant than normal.
* refers to the speed of light in a medium.
* represents the range of color tonal values that the hardware can resolve.

### density:

Population density
* Most population density affects gametophyte growth
* Population densities affect the balance of the environment
  - are higher than anywhere else in the world
  - depend to a large degree on the abundance of fruits with soft pulp
  - display great disparity in New Guinea
  - reflect subterranean burrow wall surface areas and burrow water volumes
* Some population density varies from moles.
  * is the average number of people in a place. In areas with a high population density, people live close to each other, such as in a big city. In areas with a low population density, people usually live far away from each other, such as in rural areas out in the countryside.
  - sex ratio variation in red deer
* depends foremost on prey availability
  - on the carrying capacity of the particular green
* equals total persons divided by land area in square miles.
* is affected by the level of competition and by population growth
  - also important since overcrowding almost invariably leads to disease problems
  - an important determinant of travel demand and mode choice
  - analogous to the concept of concentration in chemistry
  - another factor influencing per capita water use
  - closely related to the spread of certain diseases
  - determined from the number of individuals present per given area
  - highest along the coast and decreases as one goes inland
  - midyear population divided by land area in square kilometers
  - one person per square kilometer
  - the average number of inhabitants per square mile of land area
  - per square mile or kilometer of land
  - measure of the number per unit area
* is the number of animals per acre
  - individuals per unit area or volume
  - persons per square kilometer
  - second highest in Europe, after the Netherlands
  - typically higher along rivers, leading to mass dislocation of urban centers
* is, as in most cities, inversely correlated with distance from the center.
* measures potential threats from coastal development and pollution.
* particularly important factor in the spread of fish diseases.
* provides a useful means for comparing population distribution.
* refers to the number of people per unit of area
  - population size relative to some unit of space
* represents a demographic State indicator.
* varies considerably by area.
* varies from places
  - year to year

Power density
* depends on the set power, the spot size, and the distance of the tip from tissue.
* is an important factor in reducing costs.

### density:

Rarity
* Rarities are albums
  - scarcity
* can have a major effect on pricing.
* coupled with quality is precisely how value is determined.
* definite factor in price considerations.
* has to do with supply and demand.
* increases the value of any jewel
  - everything
  - things, thus making for a pleasant experience
* is density
  - important in all collectible fields
  - one of the most prized qualities of gemstones
  - the best indicator of vulnerability of extinction
* only intensifies the value of valuable things.
* prime determinant of a coin s value.