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basic rest-activity cycle

A biological rhythm of waxing and waning alertness with a period of approximately 90 minutes in humans. During sleep it controls the cycles of REM and slow-wave sleep. Also called the ...

46 The History of the Book in Latin America (including Incas, Aztecs, and the Caribbean)

46 The History of the Book in Latin America (including Incas, Aztecs, and the Caribbean)   Reference library

The Oxford Companion to the Book

Reference type:
Subject Reference
Current Version:
2010
Subject:
History, Social sciences
Length:
6,807 words
Publisher:
Oxford University Press
Illustration(s):
2

...ended up affecting the book industry or the business of bookselling: for example, a protectionist national policy toward papermaking in Mexico resulted in higher production costs for books. In addition, the fall in oil prices, precipitating a financial crisis that led to cycles of hyperinflation, devaluation, and economic recession in most of the region during the 1980s actually reduced the population’s income, increased book production costs, and led to declining book sales. From 1984 to 1990 , for example, Argentina produced 18 per cent fewer...

cyclicity

cyclicity   Reference library

The Oxford Companion to the Earth

Reference type:
Subject Reference
Current Version:
2003
Subject:
Science and technology, Earth Sciences and Geography
Length:
1,888 words
Illustration(s):
2

...and ‘greenhouse’ states. Second-order cycles may be driven by cycles of fast and slow mantle convection which regulate sea-floor spreading on a scale of 30 to 60 million years. Periods of Phanerozoic fast spreading are correlated with those of high magnetic field activity, which is also related to the vigour of mantle convection. When mantle activity is reduced, spreading is slower and there is a drop in sea level; magnetic polarity can be frequently reversed. There is much argument about the reality of these cycles, seemingly because they reveal an overall...

electrocardiogram

electrocardiogram   Reference library

The Oxford Companion to the Body

Reference type:
Subject Reference
Current Version:
2003
Subject:
Science and technology, Life Sciences
Length:
948 words
Illustration(s):
1

...‘peaks’ are labelled as P, QRS, and T (see figure). The most basic feature of the ECG is that the time from any one such ‘peak’ to the same one in the next cycle indicates precisely how long the heart cycle is taking. At slow rates, the timing of the waves can be easily correlated to the heart sounds heard with the stethoscope. But far more precise information can be gleaned once the relationship of the waves to the phases of the cycle is understood: The P-wave indicates the electrical activity associated with contraction of the cardiac atria, the heart's...

arousal vs awareness

arousal vs awareness   Reference library

The Oxford Companion to Consciousness

Reference type:
Subject Reference
Current Version:
2010
Subject:
Science and technology, Psychology, Philosophy
Length:
1,438 words
Illustration(s):
2

...network is also known to be the most active ‘by default’ in resting non‐stimulated conditions ( see conscious resting state ). Awareness seems not exclusively related to the activity in the frontoparietal network but, as importantly, to the functional connectivity within this network and with the thalami. Long‐range cortico‐cortical and corticothalamo‐cortical ‘functional disconnections’ have been identified in the vegetative state and recovery is paralleled by a functional restoration of the frontoparietal network and part of its cortico‐thalamocortical...

breathing

breathing   Reference library

The Oxford Companion to the Body

Reference type:
Subject Reference
Current Version:
2003
Subject:
Science and technology, Life Sciences
Length:
2,638 words
Illustration(s):
1

...change. At the end of inspiration such activity ceases fairly rapidly, allowing the lungs to deflate due to elastic recoil back to their starting lung volume at FRC. The cycle then repeats. It is generally held that during breathing at rest expiration is a mainly ‘passive’ process, although some activity in expiratory muscles may maintain the outflow of air. The inspiratory augmentation in the EMG is due to the progressive recruitment in the number and discharge frequencies (e.g. ranging from 5–25 Hz) of the active motor units in the respective muscles....

Bacteria and Archaea

Bacteria and Archaea   Reference library

Encyclopedia of Evolution

Reference type:
Subject Reference
Current Version:
2005
Subject:
Science and technology, Life Sciences, Social sciences, Anthropology
Length:
3,133 words
Illustration(s):
2

...number of microbes deriving their existence from coupling the oxidation-reduction reactions is incredibly important for the cycling of elements on earth. Global cycles, including those of carbon, nitrogen, and sulfur, are driven primarily by the metabolic activity of microbes, and it is these activities that support plant and animal life on the planet. Most of what we know about microbes and their contribution to global cycles is derived from studies of microbes that have been isolated from all other organisms and grown in “pure cultures.” Growing a...

Nuclear Industry

Nuclear Industry   Reference library

Encyclopedia of Global Change

Reference type:
Subject Reference
Current Version:
2005
Subject:
Science and technology, Environmental Science, Social sciences, Environment
Length:
5,102 words
Illustration(s):
1

...linear energy transfer radiation. Gamma rays (γ) are photons emitted from the nucleus of a radionuclide during radioactive decay. source : From Mounfield ( 1991 , p. 333). High-volume, low-activity solid wastes arise in mining and uranium ore processing at the front end of the fuel cycle, from reactor operations, and from plant decommissioning. Generally speaking, low-activity wastes contain radionuclides with short half-lives and are short-lived. Most of the world's annual total of mined uranium—around 34,000 metric tons in 1995 —is mined in Canada (32...

Population Growth and the Environment

Population Growth and the Environment   Reference library

Encyclopedia of Climate and Weather (2 ed.)

Reference type:
Subject Reference
Current Version:
2011
Subject:
Science and technology, Earth Sciences and Geography, Social sciences, Environment
Length:
2,227 words
Illustration(s):
1

...emissions of other greenhouse gases result from activities related to population size (such as agriculture, the source of a large fraction of methane and nitrous oxide emissions), population growth may exert a major influence on the buildup of greenhouse gases. Another measure of the impact of the global population on the environment is the fraction of the terrestrial net primary productivity (NPP, the basic energy supply of all terrestrial animals) directly consumed, co-opted, or eliminated by human activity. This figure is now an estimated 40 percent. Of...

Moles and Desmans

Moles and Desmans   Reference library

The Encyclopedia of Mammals (3 ed.)

Reference type:
Subject Reference
Current Version:
2007
Subject:
Science and technology, Life Sciences
Length:
2,652 words
Illustration(s):
3

...Until recently it was thought that European moles always had three active periods per day, alternating with rest periods. Recent studies of moles fitted with radio transmitters reveal a more complex picture. In the winter, males and females do show three activity periods, each of about four hours, separated by a rest of four hours in the nest. At this time they almost always leave the nest at sunrise. Females maintain this pattern for the rest of the year, except for a period in summer when they are lactating. Then they return to the nest more often in...

hearing

hearing   Reference library

The Oxford Companion to the Mind (2 ed.)

Reference type:
Subject Reference
Current Version:
2006
Subject:
Science and technology, Psychology, Philosophy
Length:
3,446 words
Illustration(s):
4

...(see the lower part of Fig. 3). A sine wave may also be called a pure tone or simple tone, since it has a very ‘pure’ or ‘clean’ quality, like that of a tuning fork or the Greenwich time signal. For a pure tone the repetition rate, the number of complete cycles per second, is the frequency. The unit of one cycle per second is called the hertz (abbreviated Hz). The Greenwich time signal has a frequency of 1,000 Hz. The highest frequency we can hear varies from 16,000 to 20,000 Hz in young adults, but tends to decrease with increasing age. The lowest frequency...

Cult

Cult   Reference library

The Oxford Encyclopedia of Archaeology in the Near East

Reference type:
Subject Reference
Current Version:
2011
Subject:
Archaeology, History
Length:
5,924 words
Illustration(s):
3

...great poetic compositions, the mythic Baal cycle, and the epic stories “Kirta” and “Aqhat,” written in a Canaanite dialect in an alphabetic cuneiform script, were unearthed; many lesser mythic texts of interest have appeared as well, some as recently as the last thirty years (see, for example, texts in Ugaritica , vol. 5, Jean Nougayrol et al., eds., Paris, 1968 ). These critical discoveries supplement the largely Phoenician mythological lore of Sakkunyaton from the first millennium; they tend to confirm the basic authenticity of much of Sakkunyaton's lore,...

Belarus

Belarus   Quick reference

A Guide to Countries of the World (4 ed.)

Reference type:
Subject Reference
Current Version:
2016
Subject:
Encyclopedias, Geographical reference, Social sciences, Regional and Area Studies
Length:
1,198 words
Illustration(s):
2

...elements of a command economy. Almost 40 per cent of industrial output still comes from state-owned enterprises and most of the rest from enterprises that are effectively under state control. Over 75 per cent of the banking industry is state-owned, and in all sectors, private business still plays a small part, and will continue to do so unless major economic reform is undertaken. Agriculture, too, is still mostly a state activity. Small farms have proliferated since independence but most output still comes from state and collective farms, the majority of...

Anthropometric History

Anthropometric History   Reference library

The Oxford Encyclopedia of Economic History

Reference type:
Subject Reference
Current Version:
2005
Subject:
Social sciences, Economics
Length:
3,886 words
Illustration(s):
4

...who grew under good nutritional circumstances have nearly identical stature. Height at a particular age reflects an individual's history of net nutrition, or diet minus claims on the diet made by work (or physical activity) and disease. Metabolic requirements for basic functions, such as breathing and blood circulation while at rest, also make claims on the diet. The synergy between malnutrition and illness may further reduce the nutrition left over for growth. Poorly nourished children are more susceptible to infection, which reduces the body's...

South and Central Asia

South and Central Asia   Quick reference

A Dictionary of World Mythology

Reference type:
Subject Reference
Current Version:
2003

...out in stark contrast with the rest of the world. For though the world cycles of Hinduism are subdivided in four yugas or ages, not unlike the Greco-Roman ages of gold, silver, brass, and iron, they follow each other in the apparently endless stream of time. The wheel of birth and death, reincarnation, encompasses the individual, the species, the social structure, the planet, the gods, the universe: it is the timescale of Nature herself. Endless, irreversible, unquenchable are the processes of alteration and change. The cycle of emanation, fruition,...

Energy and Human Activity

Energy and Human Activity   Reference library

Encyclopedia of Global Change

Reference type:
Subject Reference
Current Version:
2005
Subject:
Science and technology, Environmental Science, Social sciences, Environment
Length:
8,105 words
Illustration(s):
7

...and materials are used—often by using improved design tools to minimize materials in basic designs and to ensure that production processes operate continuously at peak performance points. Changes in the mix of industries—away from traditional materials industries—have reduced the energy intensity of industry by 10–20 percent over the past two decades. The exception is Denmark, which appears to have shifted to more energy-intensive industries. Energy and Human Activity. Figure 4. U.S. Energy Use in Manufacturing. (Energy use data from U.S. Office of...

Amazonia, Deforestation Of

Amazonia, Deforestation Of   Reference library

Encyclopedia of Global Change

Reference type:
Subject Reference
Current Version:
2005
Subject:
Science and technology, Environmental Science, Social sciences, Environment
Length:
5,326 words
Illustration(s):
2

...carbon; this is the “medium” value from Nordhaus, 1991.) [See Ecotaxation .] Loss of water cycling Water cycling is different from biodiversity and carbon loss in that impacts of deforestation in this area fall directly on Brazil rather than being spread over the Earth as a whole. [See Hydrologic Cycle .] Several independent lines of evidence indicate that about half of the rainfall in the Brazilian Amazon is water that is recycled through the forest, the rest originating from water vapor blown into the region directly from the Atlantic Ocean (Gash et...

Amazonia and Deforestation

Amazonia and Deforestation   Reference library

The Oxford Companion to Global Change

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, Environmental Science, Social sciences, Environment
Length:
5,747 words
Illustration(s):
2

...the purchase price of land today. These calculations use U.S.$7.3/ton C as the value of permanently sequestered carbon. Loss of water cycling Water cycling is different from biodiversity and carbon in that impacts of deforestation in this area fall directly on Brazil rather than being spread over the world as a whole. About 20–30% of the rainfall in the Brazilian Amazon is water that is recycled through the forest, the rest originating from water vapor blown into the region directly from the Atlantic Ocean ( Lean et al., 1996 ). Of the water entering the...

Carbon Dioxide

Carbon Dioxide   Reference library

Encyclopedia of Global Change

Reference type:
Subject Reference
Current Version:
2005
Subject:
Science and technology, Environmental Science, Social sciences, Environment
Length:
4,785 words
Illustration(s):
3

...Dioxide . Climate Change 19 (1991), 99–118. Moore B., III , and B. H. Braswell, Jr. Planetary Metabolism: Understanding the Carbon Cycle . Ambio 23 (February 1994), 4–12. CO 2 and the terrestrial biosphere Green, N. P. O. , G. W. Stout , and D. J. Taylor . Biological Science , vol. 1, Organisms, Energy and Environment. 2d ed. Cambridge: Cambridge University Press, 1990. Biology textbook that contains basic details of the biochemistry of photosynthesis. Leemans, R. Impacts of Greenhouse Gases and Climatic Change. In The Global Environment:...

Sumerian

Sumerian   Reference library

The Oxford Encyclopedia of Archaeology in the Near East

Reference type:
Subject Reference
Current Version:
2011
Subject:
Archaeology, History
Length:
2,604 words
Illustration(s):
1

...describe events with divine protagonists that take place in a supernatural world. They revolve around the gods Enki, Enlil, Inanna (and Dumuzi), Ninurta, and other deities. Epics. Two cycles of narrative texts with superhuman protagonists have been preserved: one deals with Gilgamesh (five compositions) and the other with Lugalbanda and Enmerkar (four compositions). Both cycles originated in Uruk. Historical texts. There is a very large number of commemorative royal inscriptions, from all places and dynasties. Some of them can be quite extensive, such as...

Socialism

Socialism   Reference library

The Oxford Encyclopedia of Women in World History

Reference type:
Subject Reference
Current Version:
2008
Subject:
History
Length:
3,199 words
Illustration(s):
1

...eventually, in 1848 , to an outburst of revolutionary activity across Europe. Socialists of various stripes were involved in these events, and women were visible in the public contests. For example, women in France formed clubs, published newspapers, and demanded the vote, employment, and improved working conditions. Pauline Roland , a former follower of Saint‐Simon, hoped to create cooperatives of women and men workers and advocated equality in marriage and reform of moral life. By 1851 the cycle of revolution was over; Roland was arrested, sent to a...

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