absolute intensity threshold
41Delta-sigma modulation — Delta sigma (ΔΣ; or sigma delta, ΣΔ) modulation is a method for encoding high resolution or analog signals into lower resolution digital signals. The conversion is done using error feedback, where the difference between the two signals is… …
42Audiogram — An audiogram is a standard way of representing a person s hearing loss [http://www.phonak.co.uk/ccuk/consumer/hearing/audiogram.htm] . Most audiograms cover the limited range 100Hz to 8000Hz (8kHz) which is most important for clear understanding… …
43Hemispherical photography — Hemispherical photography, also known as fisheye or canopy photography, is a technique to estimate solar radiation and characterize plant canopy geometry using photographs taken looking upward through an extreme wide angle lens (Rich 1990).… …
44Spain — /spayn/, n. a kingdom in SW Europe. Including the Balearic and Canary islands, 39,244,195; 194,988 sq. mi. (505,019 sq. km). Cap.: Madrid. Spanish, España. * * * Spain Introduction Spain Background: Spain s powerful world empire of the 16th and… …
45nervous system, human — ▪ anatomy Introduction system that conducts stimuli from sensory receptors to the brain and spinal cord and that conducts impulses back to other parts of the body. As with other higher vertebrates, the human nervous system has two main… …
46radiation measurement — ▪ technology Introduction technique for detecting the intensity and characteristics of ionizing radiation, such as alpha, beta, and gamma rays or neutrons, for the purpose of measurement. The term ionizing radiation refers to those… …
47nervous system — Anat., Zool. 1. the system of nerves and nerve centers in an animal or human, including the brain, spinal cord, nerves, and ganglia. 2. a particular part of this system. Cf. autonomic nervous system, central nervous system, peripheral nervous… …
48United States — a republic in the N Western Hemisphere comprising 48 conterminous states, the District of Columbia, and Alaska in North America, and Hawaii in the N Pacific. 267,954,767; conterminous United States, 3,022,387 sq. mi. (7,827,982 sq. km); with… …
49Earth Sciences — ▪ 2009 Introduction Geology and Geochemistry The theme of the 33rd International Geological Congress, which was held in Norway in August 2008, was “Earth System Science: Foundation for Sustainable Development.” It was attended by nearly… …
50Electron — For other uses, see Electron (disambiguation). Electron Experiments with a Crookes tube first demonstrated the particle nature of electrons. In this illustration, the profile of the cross shaped target is projected against the tube face at right… …
