humidity

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humidity

 [hu-mid´ĭ-te]
the degree of moisture in the air.
absolute humidity the actual amount of vapor in the atmosphere, expressed in milligrams per liter.
relative humidity the percentage of moisture in the air as compared to the amount necessary to cause saturation, which is taken as 100.
humidity therapy the therapeutic use of water to prevent or correct a moisture deficit in the respiratory tract. Under normal conditions the respiratory tract is kept moist by humidifying mechanisms that allow for evaporation of water from the respiratory mucosa. If these mechanisms fail to work, are bypassed (such as with an endotracheal tube), or are inadequate to overcome the drying and irritating effects of therapeutic gases and mucosal crusting, some form of humidification must be provided.

The principal reasons for employing humidity therapy are: (1) to prevent drying and irritation of the respiratory mucosa, (2) to facilitate ventilation and diffusion of oxygen and other therapeutic gases being administered, and (3) to aid in the removal of thick and viscous secretions that obstruct the air passages. Another important use of water aerosol therapy is to aid in obtaining an induced sputum specimen.

Humidity therapy may be delivered in a variety of ways. Humidifiers and vaporizers increase the water content of an environment and are limited to the treatment of upper respiratory disorders because they produce particles that are too large to penetrate deeply into the lungs. Nebulizers generate clouds or mists of particles that are extremely small and thus capable of penetrating more deeply into the bronchioles and small structures of the lower respiratory tract. Examples of these include jet instruments and ultrasonic nebulizers.

hu·mid·i·ty

(hyū-mid'i-tē),
Moisture or dampness, as of the air.
[L. humiditas, dampness]

hu·mid·i·ty

(hyū-mid'i-tē)
Moisture or dampness, as of the air.
[L. humiditas, dampness]

hu·mid·i·ty

(hyū-mid'i-tē)
Moisture or dampness, as of the air.
[L. humiditas, dampness]
References in periodicals archive ?
Genetic correlation between breeding values at temperature-humidity index (THI) [less than or equal to] 72 (no heat stress) and breeding values at a given THI for milk yields.
Distribution, mean, and standard deviation of milk by calving season, calving age, and temperature-humidity index >72 Variable Class Observations % Calving season Apr.-Aug.
Temperature-humidity index levels in tropical areas could influence the reproductive development of animals in early postpartum affecting conception rate.
Heuwieser, "Impact of heat stress on conception rate of dairy cows in the moderate climate considering different temperature-humidity index thresholds, periods relative to breeding, and heat load indices," Theriogenology, vol.
Mean air temperature and the difference between the mean indoor and outdoor air temperature (mean [DELTA]t) (A), mean air relative humidity (B), and mean temperature-humidity index (C) in the indoor and outdoor environments of the poultry house
Maps of temperature-humidity index (THI) distribution across the poultry house in the day- and nighttime periods.
Temporal trends of the evaluated monthly temperature-humidity index (THI mean, max, and min %) during the studied period (from 2001 Jan to 2013 Oct) in central Taiwan.
The temperature-humidity index is usually used as an indicator of thermal stress in cows (Armstrong, 1994).
The highest values of temperature-humidity index (THI) were recorded at the hottest hours of the day (Figure 2), from 9 to 15 h (73.4 and 73.7).
Seasonal pattern of mortality and relationships between mortality and temperature-humidity index in dairy cows.

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