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1. An act that requires use of resources or time. In Program Evaluation and Review Technique (PERT), an activity is represented by an arrow on a PERT chart.

2. In investing, the amount of a security's relative trading volume; that is, the amount of money flowing into and out of a security in trading. A high amount of activity means that many shares of the security are being bought and sold at a high rate, while a low level of activity indicates the opposite.


The amount of relative trading volume in a security.
References in periodicals archive ?
The enzyme activity was found to be increased from 10.5 to 19.6 U/mL when the concentration of Tween-80 was increased from 0.1 to 0.7% respectively.
(14) Conversely, free [beta]-galactosidase showed the highest enzyme activity at 47[degrees]C, while it was at 57[degrees]C after the enzyme was cross-linked to the gelatin carboxymethlyselulose carrier.
When observing the effect of the molybdenum doses, it was verified that the activity of the nitrate reductase in the V3 stage, with the presence of the inoculant, framed into a quadratic polynomial model, and the dosage which provided higher enzyme activity was 39,65 g of Mo.100 [kg.sup.-1] of seed.
Effect of pH on enzyme activity was investigated by testing the enzyme assay at different pH ranging from 5 to 9 by using the following buffer systems: 0.1 M sodium acetate (pH 4-5.5); 0.1 M sodium phosphate (pH 6-7.5); 0.1 M glycine NaOH (pH 9.5-12) under standard assay condition (22).
Our study showed that a low number of leukocytes is one of the critical factors affecting enzyme activity. Therefore, it is crucially important to interpret the data taking into account the leukocyte number in order to decrease the number of recall patients and the false-positive ratio.
Under these conditions, mean urease activity was 25.16% and 1.46% higher than under [P.sub.F] and [P.sub.N] conditions respectively, whereas mean ALP activity was 18.42% and 16.89% higher under [P.sub.H] than under [P.sub.F] and [P.sub.N] respectively and mean catalase enzyme activity was 24.20% and 17.24% higher under [P.sub.H] than under [P.sub.F] and [P.sub.N] respectively.
However, the higher pH range (pH 7.5-pH 8.0) would inhibit the enzyme activity (from 0.194 [+ or -] 0.001 to 0.185 [+ or -] 0.001 U/mg biomass, resp.).
Substantially high [PLA.sub.2] enzyme activity from Aedes albopictus was recorded in gut plus content preparation (M = 0.328, SEM = 0.00) and gut content preparation (M = 0.3067, SEM = 0.01).
Some studies indicated that enzyme activity and microbial biomass can vary high both seasonal and interannual (Sardans et al., 2008).
The available sources have not described the saliva used as a material to explore the enzyme activity in lung cancer.