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Subject: Music

This US group was formed in Los Angeles, California, in 1978 by Steve Allen (guitar, vocals) and Ron Flynt (bass, vocals), two expatriate musicians from Tulsa, Oklahoma. Drummer Mike Gallo ...

texture

texture   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015
Subject:
Science and technology, Life Sciences, Social sciences, Environment
Length:
115 words
Illustration(s):
1

...The particles that give soil its texture are defined by their size according to UK, US, and international systems of soil classification . See diagram. Texture Fraction UK US International Stones and  gravel >2.0 mm >2.0 mm >2.0 mm Coarse  sand 2.0–0.2 mm 2.0–0.2 mm 2.0–0.2 mm Fine sand 0.2–0.06 mm 0.2–0.05 mm 0.2–0.02 mm Silt 60–2 μ ‎m 50–2 μ ‎m 20–2 μ ‎m Clay <2 μ ‎m <2 μ ‎m <2 μ...

barchan

barchan   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015
Subject:
Science and technology, Life Sciences, Social sciences, Environment
Length:
59 words
Illustration(s):
1

...mobile dune in a sand desert in which the wind blows predominantly from one direction. The dune moves by the erosion of sand from the windward slope and its accumulation on the steeper lee or slip slope, which stands at about 32°. Average velocities of dune movement are 10–20 m/yr....

secchi disc

secchi disc   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015
Subject:
Science and technology, Life Sciences, Social sciences, Environment
Length:
92 words
Illustration(s):
1

...disc A disc used in a simple method for measuring the transparency of water. The disc is 20 cm across and divided into alternate black and white quadrants. It is lowered into water on a line until the difference between the black and white areas just ceases to be visible, at which point the depth is recorded. The secchi disc provides a convenient method for comparing the transparency of water at different sites. The disc was invented by the Italian Jesuit and eminent astrophysicist Angelo Secchi ( 1818–78 ). Secchi...

ozone layer

ozone layer   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015
Subject:
Science and technology, Life Sciences, Social sciences, Environment
Length:
241 words
Illustration(s):
4

...layer The stratospheric layer at 20–30 km altitude, in which ozone (O 3 ) is concentrated at 1–10 parts per million (220–460 DU). Ozone also occurs in very low concentrations at altitudes of 10–15 km and 30–50 km. The highest ozone concentration is found at about 30 km over the equator and about 18 km over the poles. Atmospheric ozone is produced by the photochemical dissociation of oxygen (O 2 ), resulting from the absorption by oxygen molecules of ultraviolet radiation ( UV ) at a wavelength of 240 nanometres and an energy of 5.16 electron volts (known...

rain-gauge

rain-gauge   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015
Subject:
Science and technology, Life Sciences, Social sciences, Environment
Length:
277 words
Illustration(s):
1

...A device for measuring the amount of rainfall. Two types are widely used. The standard rain gauge, approved for use at all weather stations, is designed to collect rain while minimizing losses due to evaporation. The gauge comprises a cylinder 20 cm in diameter, closed at one end, that is set on open ground with its upper rim 1 m above ground level. Rain falling on to the gauge enters a collecting funnel that directs it into a calibrated measuring tube, 6.32 cm in diameter, inside the cylinder. The cross-sectional area of the measuring tube is...

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