Ecological Sustainability

424 Glossary

joule: The SI unit of energy or work. 1 J ≡ 1 N-m = 0.239006 g-cal = 0.000948451

Btu. A joule is a relatively small energy unit, for example, 1 kWh =

3.60 × 10

6

J.

Kermack–McKendrick models for epidemics: Mathematical compartmen-

tal models using ODEs to describe the dynamics of the spread of

an infectious disease. Some models include infection latent period;

recovery; deaths; conferred immunity; as well as the use of antivi-

rals, antibiotics, and quarantines.

kerogen: A mixture of organic chemical compounds found in certain shale

rock deposits. Kerogen is formed naturally as the rst step in pro-

ducing crude oil. The high temperatures and pressures underground

accelerate the breakdown of algae, diatoms, plankton, spores, pollen, ...