FIELD U 

 Columns 65 and 66 



MISCELLANEOUS TIME VALUES 



A. Duration of response 



(time after response begins ) 



1. Duration of response 



2. Duration of delay of death 



(alteration of survival time) 



B. Duration of the period 



preceding response 



3. Time to response: 



3a. Time to any response other than 



death 

 3b. Time to death (killing time) 



C. Duration of a compound's 



ability to produce response 



4. Persistence of the activity of a 



residue of the test compound 



Organization 



A series of overlapping scales have been prepared for this field (corresponding exactly to the 

 symbols assigned to Field P). Each scale covers a limited time period, each period having been 

 selected in such a way that all data from a single type of test can usually be coded by employing only 

 a single scale in Field U. The first column of this two-column field is used to designate the scale 

 being used and the second column indicates a specific time range. 



For a full explanation of the organization of the time scales, see the discussion of the organ- 

 ization of Field P. 



General Use 



Field U has four basic uses, each having to do with time values concerned with the test 

 compound's action. The several uses do not present problems of conflict (i. e. , they do not compete 

 for the use of Field U), since each occurs only with a test situation that excludes the other uses (with 

 the possible exception of Uses 1 and 3a which, however, do not constitute a serious problem of 

 choice). There are distinguishable three general categories of the time values coded in the field, 

 (A) duration of the response, (B) time, after the beginning of administration of the test compound, to 

 the beginning of the specific response, and (C) persistence of activity of a residue of the test compound. 

 The specific uses of the field are briefly outlined below, under these three categories. In this outline, 

 the uses are described as being two specific time periods of Category A (1 and 2), one time period of 

 Category B (subdivided in the list as 3a and 3b, however, according to the specific action being death 

 or other-than-death), and one time period of Category C (4). These four specific uses are each dis- 

 cussed in the Specific Directions and Explanations section. 



Field U can be used to express: 



A. A time period during which the organism responds to the test compound, the end of the 

 period marking the limit of the test compound's competence relative to the response it 

 induced. The two time values of this category for which Field U may be used are as 

 follows: 



1. To express the DURATION OF ACTION of the test compound 



"Duration of action" is defined as the period of time, following the end of the appli- 

 cation of the test compound to the organism, during which time the test compound 



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