flow

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flow

a measurement of quantity over a specified period of time. Unlike a STOCK, which is not a function of time, a flow measures quantity passing per minute, hour, day or whatever. A common analogy is to a reservoir. The water entering and leaving the reservoir is a flow but the water actually in the reservoir at any one point in time is a stock. INCOME is a flow but WEALTH is a stock.
Collins Dictionary of Economics, 4th ed. © C. Pass, B. Lowes, L. Davies 2005
References in periodicals archive ?
aeruginosa Study start Study end median (IQR) median (IQR) [FEV.sub.1] Total group 78 (61-101) 61 (49-94) PA-negative 99.5 (78-105) 97 (60-107) PA-colonised 71 (41-83) 50 (23-68) FVC Total group 87 (73-95) 77 (52-94) PA-negative 93 (81-104) 97 (71-114) PA-colonised 84 (56-87) 67 (41-80) [FEF.sub.25-75] Total group 70 (38-106) 43 (22-107) PA-negative 105 (55-118) 109 (69-138) PA-colonised 38 (18-87) 22 (11-42) PA = Pseudomonas aeruginosa; IQR = interquartile range; [FEV.sub.1] = forced expiratory volume in 1 second; FVC = forced vital capacity; [FEF.sub.25-75] = forced expiratory flow over 25-75% expiration.
The spirometric parameters of interest are forced vital capacity (FVC), forced expiratory flow in 1 second ([FEV.sub.1]) and [FEV.sub.1]/FVC ratio.
Maximum mid expiratory flow or Forced Expiratory Flow between 25% to 75% of the Vital capacity(FEF 25-75%) is indicative of early obstructive disease when the FEV1/FVC ratio is normal11.
The FEF[logical not]25-75 is the forced expiratory flow rate between 25 and 75 percent of the forced vital capacity.
In children, the forced expiratory flow over the middle half of forced vital capacity, or [FEF.sub.25%-75%], is a more sensitive indicator of airflow obstruction than is [FEV.sub.1], Dr.
THE EFFECT OF BODY POSITION ON MAXIMUM INSPIRATORY AND EXPIRATORY PRESSURES AND FORCED EXPIRATORY FLOW. (2) Nichols, Travis; (3) Osborn, Amy; (4) Tindall, Kelly; (1) Hiebert, Jean M.
Forced vital capacity (FVC), forced expiratory volume in one second ([FEV.sub.1]), forced expiratory flow at 50 and 75 per cent of the vital capacity (FEF 50 and 75%), forced expiratory flow between 25 and 75 per cent of the vital capacity ([FEF.sub.25-75]) total lung capacity (TLC) and residual volume (RV) data were obtained using constant volume variable pressure body plethysmograph (PK Morgan, Chatham, Kent, UK).
This may also be represented by the abbreviations MFR (Maximum Flow Rate) or MEFR (Maximum Expiratory Flow Rate, or FEFmax (Forced Expiratory Flow Rate Maximum).
Although no studies looked specifically at exacerbation rates, multiple clinical and biologic outcomes (symptom scores, quality of life measures, bronchodilator use, forced expiratory flow in 1 second [FE[V.sub.1]], and peak expiratory flow rate [PEFR]) improved with nedocromil use compared with placebo.
(FE[V.sub.1] is the amount of air forcefully exhaled during the first second following a full inspiration, and FVC is the total volume exhaled.) Pulmonary function was also assessed by measuring the forced expiratory flow during the middle half of the FVC (FE[F.sub.25-75%]).
Results: The investigators found that the vitamin supplements protected the study group from the decreases in forced expiratory flow, the amount of air dispelled from the lungs during a certain time period and peak expiratory volume, a measure of airway resistance, that were seen among those who received placebo pills.

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