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intake

 
Dictionary: in·take   (ĭn'tāk') pronunciation
n.
  1. An opening by which a fluid is admitted into a container or conduit.
    1. The act of taking in.
    2. The quantity taken in.
    3. Something, especially energy, taken in.

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Dental Dictionary: intake
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n

The substance or quantities thereof taken in and used by the body.

Architecture: intake
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An opening through which water or air (or any other fluid) enters a system, chamber, plenum, pipe, or machine. Also see outside-air intake.


Intake is an umbrella term that refers to the act of taking something in. The term "intake" is often used in relation to food and drink, to describe how and how much is ingested. It also relates to behavior, since mental processing is involved in the action of eating and drinking. That is, physical and social stimuli are involved in feeding and drinking behaviors in terms of controlling the movements of gathering and ingesting materials; internal stimuli such as metabolism and circulating substrates also play a role. Intake of food and drink interests natural and social sciences as it is a vital behavior to sustain life that is also shaped by culture and society.

Behavioral Organization of Intake

The behavioral organization of intake involves perception of the sensory characteristics of food and drink. Physical and chemical properties of food and drink that can be sensed by the eater provide information about their nature. Orosensory attributes (that is, those relating to both taste and the other senses) can be detected by sight and sound, smell, irritance, taste, and touch. Food and drink can be appealing based on their orosensory properties. And the first mouthfuls of food can send substrates around the body within minutes.

Intake can be adjusted according to nutritional needs when orosensory characteristics are associated with the postingestive (metabolic) effects of food and drink. Orosensory characteristics can thus become cues that predict postingestional effects specific to foods and drinks. These cues can be unlearned (innate, sweet taste) or learned (acquired, bitter taste). While sweet stimuli mean energy, perhaps from carbohydrate, bitter stimuli are a cue to alkaloid toxins. From an evolutionary standpoint, it has been hypothesized that the liking for sweetness ensured animals' survival. In animals and humans, learning plays an important role in food intake. The acquisition of a taste for nutrients and an aversion for toxic substance are also vital. Behavioral and physiological analysis of the learning of pre-and postingestive control of intake was developed by French physiologist Jacques Le Magnen. His original contributions include findings on conditioned sensory aversions, carbohydrate-conditioned sensory preferences, and control of meal size.

Social and Cultural Organization of Intake

Intake is also organized according to food availability. In terms of the latter, we see the great contrast between industrialized countries where food is available in abundance and Third World countries where hunger afflicts poor people due to food scarcity. Our ancestors' intake was mainly dependent on plant food gathering, hunting, and fishing. Later on, domestication of food and animals and the development of food preservation enabled human societies to improve food availability. However, in parts of the world not well suited for cultivation, pastoralists still acquire their food from their herds of domesticated animals. Herding allows them to transform nonedible plant matter into animal products.

Intake is also determined by the culture of human groups. Learned cultural knowledge affects food choices. Socially transmitted knowledge about food includes norms, religious, or cult values, as well as myths, superstitions, taboos, and fads. The intake of certain kinds of plant and animal foods can be culturally prohibited. For example, cattle are killed for meat in many parts of the world, while traditional Hindus forbid killing cattle for meat because of their use in agriculture. Dogs serve as pets and companions in American culture while serving as food in other cultures, illustrating how intake is motivated by symbolic values of the food rather than its survival value. However, sociocultural influences do not act alone and interact with the individual's biology to determine intake.

Control of Intake

Investigations concerned with the control of intake have used various peripheral and central approaches. This has led to theories of the mechanisms controlling intake, such as the glucostatic (transient change of blood glucose), the lipostatic (fat metabolism and body fat stores), the thermostatic (thermic effect of food), and the aminostatic (essential amino acid) hypotheses. Although intake was shown to be facilitated or inhibited by a variety of substrates, the behavioral mechanisms remain to be identified. Neural bases of food intake have evolved from the those prevalent in the 1950s, focusing on appetite and satiety brain centers located in the hypothalamus, to the current hypothesis that macronutrient intake is controlled by precise synaptic pathways. Food intake might indeed be guided by macronutrient selection. However, experiments that involve presenting laboratory animals with two or more diets differing in their nutrient content in an attempt to understand brain mechanisms that control intake involves the inclusion of confounding factors. Indeed, many drugs that affect central nervous system neurotransmitters and peptides also act on sensory pathways. Therefore, unless the confounding sensory attributes of food have been excluded, one cannot conclude that the subsequent food intake is controlled by the macronutrients. This principle was applied by examining studies using sensorily contrasting forms of various macronutrients, and only brain serotonin was found to affect carbohydrate intake while the effects of catecholamines and opiates on macronutrients were not substantiated.

Intake is also motivated by factors external to the food or the drink itself. Age, sex, physiological state, nutritional state, emotions, stress, number of people present, peer groups, food trends, social pressures (body image), as well as beliefs related to food safety (for example, food beliefs related to mad cow disease, genetically modified foods, pesticide-free or organic food) are known to influence intake. Other external factors that affect intake include food availability, food cost, as well as environmental factors (season, temperature, and so forth). In addition, animal and human studies have revealed that food and macronutrient intake is related to circadian rhythms, and that food intake is concentrated during the period of main activity (for example, during the day) and is related to predictable rhythms of macronutrient selection.

Expressing Intake

Intake of food and drink is often estimated by dietary measurement of daily intake of energy (kilocalorie [kcal], kilojoules [kJ]) and nutrients (carbohydrate, protein, lipid, vitamins, and minerals. Units such as the gram (g), milligram (mg), microgram (μg), International Unit (IU), and so forth are used, as well as established human nutrition methodologies such as food diary, food recalls, food frequency questionnaires, and so on. Intakes are then qualified as adequate or inadequate based on nutritional recommendations. Nutritional research methods need to be improved by assessing cognitive perception and control of eating.

Facilitated intake and its inhibition are expressed in various ways. Among terms used to describe facilitated intake or events surrounding it are appetite, hunger, palatability, motivation to eat, and (sensory) preference. If intake is inhibited, terms such as satiety, satiation, appetite inhibition, or even satiety disinhibition are used. These terms are often used to interpret sets of quantitative data such as amount eaten during the day, meal size, ingestion rate, or numbers calculated from scales rating the hunger state. Although these measurements do not assess cognitive processes controlling intake, their direction is translated into words describing behaviors. The experimental design is therefore crucial to identify causal processes involved in intake; for example, unchanged quantitative intake while rate of intake is reduced could be interpreted as decreased pleasure while sensory preference remains unaffected.

Implications

Insufficient intake results in chronic malnutrition and periodic massive starvation. Related health problems are numerous, and include the impact of the permanent effect of energy–protein deficiency on brain development (in early childhood), parasitic diseases, and high rates of infant mortality. Controlling population growth and a better allocation of resources were proposed as solutions to world hunger. The problem of hunger could also be alleviated by technology transfer in which new technologies and crop variety could improve food production.

Disordered intake can lead to health problems such as obesity, cardiovascular disease, diabetes, alcoholism, as well as disordered eating in athletes and the eating disorders of restrictive eaters, anorexics, and bulimics. Interestingly, these health problems often arise in countries where food is abundant. Intake of specific macronutrients has been linked to diseases, for example, intake of carbohydrates has been linked to diabetes, and fat intake has been linked to heart disease, as well as to some cancers. Therefore, a better understanding of how intake is controlled could provide precious tools enabling one to intervene effectively or even prevent the development of nutrition-related pathologies.

Bibliography

Berthoud, Hans-Rudolf, and Randy J. Seeley. Neural and Metabolic Control of Macronutrient Intake. Boca Raton, Fla.: CRC, 2000.

Booth, David A. Psychology of Nutrition. London: Taylor & Francis, 1994.

Peoples, James, and Garrick Bailey. Humanity: An Introduction toCultural Anthropology. Belmont, Calif.: West/Wadsworth, 1997.

Stricker, Edward M. Handbook of Behavioral Neurobiology, vol. 10, Neurobiology of Food and Fluid Intake. New York: Plenum, 1990.

Thibault, Louise, and David A. Booth. "Macronutrient-Specific Dietary Selection in Rodents and Its Neural Bases." Neuroscience and Biobehavioral Reviews 23 (1999): 457–528.

Thibault, Louise, and David A. Booth, eds. "The Role of Orosensory and Postingestional Effects of Food in the Control of Intake. Jacques Le Magnen, 1955–1963." Appetite 33 (1999): 1–59.

—Louise Thibault

The substances, or the quantities thereof, taken in and utilized by the body. The record of intake and output is called fluid balance record.

Wikipedia: Intake
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An intake , or especially for aircraft inlet, is an air intake for an engine. Because the modern internal combustion engine is in essence a powerful air pump, like the exhaust system on an engine, the intake must be carefully engineered and tuned to provide the greatest efficiency and power. An ideal intake system should increase the velocity of the air until it travels in to the combustion chamber, while minimizing turbulence and restriction of flow. Alongside with development of jet-engine, and logical increase in overall speed of the system, it was necessary to achieve such inlet design to perform optimal air flow at any speed, generally, and in other hand - not to suppress work of first stage of compressor (of a jet-engine), by slowing down the speed of air at just under subsonic at entrance to the compressor, keeping the necessary air flow at optimum (for given output power). That led to "inverse droplet" design of air-spike (conus, or semiconus, in some designs) as most common idea under the design of supersonic, and hypersonic inlet. All the above is usually accomplished by flow testing on a flow bench in the port design stage. Cars with turbochargers or superchargers which provide a pressurized intake system, usually have extensive tweaking of the intake system to improve performance dramatically.

A modern air intake system should have three main parts, an air filter, mass flow sensor, and throttle body. Many cars today now include a silencer to minimize the noise entering the cabin. Silencers impede air flow and create turbulence which reduce total power, so many performance enthusiasts often remove them.

Production cars have specific length air intakes to cause the air to vibrate and buffett at a specific frequency to assist air flow in to the combustion chamber. Aftermarket companies for cars have introduced larger throttle bodies and air filters to decrease restriction of flow at the cost of changing the harmonics of the air intake for a small net increase in power or torque.

Porsche in the 1980s designed an intake system for their cars that changed the length of the intake system by alternating between a longer and shorter set of tubing using a butterfly valve, creating a small amount of positive pressure which increased overall performance of the engine.

Alfa Romeo used variable-length intake in their 2.0 Twin Spark engines powering the model 156.

See also

External links


Translations: Intake
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Dansk (Danish)
n. - indtag, indløb, indtagelse, optagelse, indsugning, ventilation, krafttilførsel

Nederlands (Dutch)
opneming, inlaat, opgenomen energie

Français (French)
n. - (École, Univ, Admin) admissions (npl), inspiration (d'air), (Tech) arrivée

Deutsch (German)
n. - Einlaß, Aufnahme, Ansaugen, Einströmungsöffnung, Zuflußrohr, aufgenommene Menge

Ελληνική (Greek)
n. - εισαγωγή, είσοδος, εισροή, αναρρόφηση

Italiano (Italian)
presa (idraulica, elettrica ecc...), nuovo ammesso (ad organizzazione), immissione

Português (Portuguese)
n. - entrada (f), ato (m) de fazer entrar, consumo (m)

Русский (Russian)
втягивание, потребление, пополнение, водозабор

Español (Spanish)
n. - toma, entrada, admisión

Svenska (Swedish)
n. - intag (för vatten e.d.), inlopp, tillförsel, ventilationsschakt, antal intagna (rekryterade), intagning (i ett plagg), förundersökning, nyodling (på myr e.d.), hoptagning (vid stickning)

中文(简体)(Chinese (Simplified))
引入口, 通风口, 入口

中文(繁體)(Chinese (Traditional))
n. - 引入口, 通風口, 入口

한국어 (Korean)
n. - 통풍구멍, 섭취량, 수입, 채용인원

日本語 (Japanese)
n. - 吸込み, 入力, 取入れ口, くびれ, 取り入れ口, 摂取, 摂取量

العربيه (Arabic)
‏(الاسم) عمليه إدخال سائل, غاز, الخ إلى آله, فتحه الإدخال, دفعه‏

עברית (Hebrew)
n. - ‮קליטה, מספר הנקלטים, פתח הכניסה, מקום כניסת מים, דלק, אוויר וכו' למערכת, אדמת ביצה מיובשת (בריטניה)‬


 
 

 

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Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.  Read more
Dental Dictionary. Mosby's Dental Dictionary. Copyright © 2004 by Elsevier, Inc. All rights reserved.  Read more
Architecture. McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc. All rights reserved.  Read more
Food & Culture Encyclopedia. Encyclopedia of Food and Culture. Copyright © 2003 by The Gale Group, Inc. All rights reserved.  Read more
Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Intake" Read more
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