activity


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activity

1. the number of disintegrations of a radioactive substance in a given unit of time, usually expressed in curies or disintegrations per second
2. 
a. the capacity of a substance to undergo chemical change
b. the effective concentration of a substance in a chemical system. The absolute activity of a substance B, λB, is defined as exp (μBRT) where μB is the chemical potential

activity

[‚ak′tiv·əd·ē]
(computer science)
The use or modification of information contained in a file.
(nuclear physics)
The intensity of a radioactive source. Also known as radioactivity.
(physical chemistry)
A thermodynamic function that correlates changes in the chemical potential with changes in experimentally measurable quantities, such as concentrations or partial pressures, through relations formally equivalent to those for ideal systems.
(systems engineering)
The representation in a PERT or critical-path-method network of a task that takes up both time and resources and whose performance is necessary for the system to move from one event to the next.

activity

In CPM terminology, a task or item of work that must be performed in order to complete a project.
References in periodicals archive ?
Introduce Each Activity Before Distributing Materials A common teaching error is giving students access to materials before activities are introduced.
Some IDEFO and other modeling purists would argue that the "obtain information" activity should not be shown because it does not show a transformation.
Texas: A comptroller's decision, citing both the Massachusetts Supreme Court case discussed above and the Virginia Supreme Court case discussed below, provided that this type of activity was protected under P.
The Contract Activity Package (CAP) as designed by Rita Dunn (1992) served as the model for the creation of the lessons plans that would be used as independent study activities for the elementary students.
The routine activity theory explains how changes in daily patterns or activities of social interaction, such as employment, recreation, educational endeavors, and leisure activities, affect differences in crime rates.
A 1996 government report confirmed Kostrubala's findings; the report, Physical Activity and Health--A Report of the Surgeon General, documented that the mental and emotional benefits of physical activity help to reduce anxiety, symptoms of depression, and even improve mood--along with the proven physical benefits in rehabilitation.
No such brain-related pain effects occurred for the remaining 24 participants, who were instructed to change their brain activity when they were outside the fMRI machine or in the machine but receiving no feedback, when they received feedback from brain areas unrelated to pain, or when they viewed someone else's pain-related brain activity.
What are the policies that affect our opportunities for physical activity and have allowed the growth of the physical inactivity industry?
Reports required of MSBs usually fall into two categories: currency transaction reports and suspicious activity reports.
District 7--Chicago: The economy continued to grow moderately in late February and March, although activity lagged in Michigan.
The Notice provides that (with the exception of production activities performed by one member of an expanded affiliated group for another member), if one taxpayer performs a qualifying activity under section 199(c)(4)(A)(i) pursuant to a contract with another party, only the taxpayer that has the "benefits and burdens" of ownership of the property under federal income tax principles during the period of the qualifying production activity is treated as having engaged in that activity.
A new section is provided that is based on section 4(k) of the BHC Act, which discusses the Board's October 2, 2003, approval of an FHC's notice under section 4 of the BHC Act to engage in physical commodity trading activities on a limited basis as an activity that is complementary to the financial activity of engaging regularly as principal in commodity derivative activities.

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