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A20

A cytoplasmic zinc finger protein (790 aa) that inhibits NFκB activity and TNF-mediated programmed cell death. The expression of the A20 mRNA is upregulated by TNFα. It is a dual function ...

arid climate

arid climate   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...climate A climate with an aridity index of 0.05–0.20...

secular variation

secular variation   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...variation Any long-term variation over a period of about 10 to 20 years or...

chain

chain   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...An imperial measure, equal to 22 yards (20.11 m), that was a unit of length formerly used by foresters and land surveyors (10 sq. chains = 1 acre...

mixed woodland

mixed woodland   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...woodland A woodland in which the minority of trees, but amounting to not less than about 20 per cent, are either coniferous or...

halo spot

halo spot   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...spot A disease of barley and other cereals, caused by the fungus Septoria oxyspora ( Selenophoma donacis ). Lesions on upper leaves have pale centres with dark margins. The disease is important in only a few regions of Britain, including the wetter western regions of England, Wales, and Ireland. http://archive.hgca.com/minisite_manager.output/3670/3670/Cereal%20Disease%20Encyclopedia/Diseases/Halo%20...

kastanozems

kastanozems   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...Soils that have a mollic horizon more than 20 cm deep and also concentrations of calcium compounds within 100 cm of the surface. Kastanozems are a reference soil group in the World Reference Base for Soil Resources...

stratified random sample

stratified random sample   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...a modification of the random sample that is particularly useful when obvious heterogeneity exists in the community , area, etc. to be investigated. In such instances a simple random sample may fail to record sufficient replicates of a particular subcategory, or may do so only very inefficiently, so preventing a proper statistical monitoring of variability. In a stratified random scheme sample points are shared among the main types present, then allocated at random within those subcategories. http://www.stat.ualberta.ca/~prasad/361/STRATIFIED%20RANDOM%20...

ripple

ripple   Quick reference

A Dictionary of Ecology (5 ed.)

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Subject Reference
Current Version:
2015

...A small-scale ridge of sand produced by flowing water, wind motion, or wave action. The wavelength or spacing of ripple crests is usually less than 50 cm and the heights are less than 20...

folic horizon

folic horizon   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...horizon A soil horizon more than 10 cm thick, found at or close to the surface, that contains more than 20 per cent organic carbon (35 per cent organic matter) by...

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

... sand , silt , and clay in the fine earth of a soil sample, which give a distinctive feel to the soil when handled and are defined by classes of soil texture. 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...

seed bank

seed bank   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...bank A store in which seeds are held as a means of conserving plant species . Maintained at a constant temperature of 0°C and dried to a moisture content of about 4 per cent, seeds of many species remain viable for up to 20 years. See gene bank . Compare recalcitrant seed ; soil seed bank...

‘eye’ of storm

‘eye’ of storm   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...of storm The central part of a tropical cyclone, where winds are light, skies are generally clear, and there is a slight, horizontal pressure gradient. The diameter of the ‘eye’ averages 20 km but in a large cyclone can be 40 km or more. The ‘eye’ is an area of some air subsidence which produces adiabatic ...

clay

clay   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...1 A soil separate comprising mineral particles less than 2 μ ‎m in diameter. 2 In the Udden–Wentworth scale, particles less than 4 μ ‎m in diameter. 3 A class of soil texture, usually containing at least 20 per cent by weight of clay particles. Compare clay mineral...

sand ribbon

sand ribbon   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...ribbon A longitudinal strip of sand , up to 15 km long, 200 m wide and less than 1 m thick, standing on, and surrounded by, an immobile gravel floor. Sand ribbons are developed on the sea floor of the continental shelf where there is a paucity of sand, with water depths of 20–100 m and fast-flowing...

SPOT

SPOT   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

... ( Système Probatoire d’Observation de la Terre ) A series of five French observation satellites, built in collaboration with Belgium and Sweden, which were launched between 1986 and 2002 , that scan a surface track 67 km wide with 20 m multispectral and 10 m monospectral resolution. http://eoedu.belspo.be/en/satellites/spot.htm Detailed information....

startle response

startle response   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...response The reaction of an animal to sudden danger, by a threat display (e.g. when certain butterflies and moths reveal eyespots on the wings) or flight (e.g. on average it takes 20 milliseconds for a puff of air from an approaching missile to set an American cockroach...

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

... ( adjective barchanoid ) A crescent-shaped 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....

polar-desert soil

polar-desert soil   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...soil A mineral soil that lacks identifiable soil horizons , and has almost no surface humus . It is associated with arid, polar-desert environments where precipitation is less than 130 mm annually, plant cover less than 25 per cent, and thawed, active soil is 20–70 mm...

shoreface

shoreface   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...The subtidal coastal zone between the low-water mark and a depth of about 10–20 m. The lower limit of the shoreface corresponds to the position at which waves begin to affect the seabed (wave base), and therefore wave action governs the processes active in this...

abyssalpelagic zone

abyssalpelagic zone   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...zone The part of the pelagic zone of the ocean that overlies the abyssal plain . It extends from a depth of between 2000 m and 4000 m to about 6000 m. The temperature is about 4°C and the pressure 20–60 MPa. See ocean divisions...

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