MalariaControl.net can handle a lot of different sorts of variable, from the changing density of parasites within a human host as an infection progresses to the sort of treatment available in different places around the continent.

ECONOMIST: Linking up computers to defeat malaria

The density of water molecules within the leaf is typically 60 times greater than the density of carbon dioxide in the air, and the diffusion rate of the water molecule is greater than that of the carbon-dioxide molecule.

WSJ: Harrison H. Schmitt and William Happer: In Defense of Carbon Dioxide

The firm says the low power-density of its lasers and a series of safeguards ensures that human exposure remains within regulatory limits.

ECONOMIST: Wireless charging

He estimates a threefold expansion in mobile connections within five years that would take total subscribers to 235 million and wireless density to 20%.

FORBES: The War Is Over

They measured the density of lymph vessels around the melanomas, and then assessed which patients actually went on to develop secondary cancers within eight years.

BBC: NEWS | Health | Spread of skin cancer predicted