INDEX many-body response

A further consideration that is very important in whole animal studies is the inter-individual variation in response to treatment. This variation can be quite high between animals and it has been recommended that at least 10 animals per treatment be used if one wishes to quantify apoptosis in a tissue (4). A final item that can become a concern is those situations where the basal apoptotic index is very low (<0.1 %), in which case counting sufficient apoptotic bodies to obtain an index of sufficient confidence may warrant the counting of far more cells than originally intended, perhaps as many as 6000 (3,44). 

Frequency Weighting. The inverse frequency contour (i.e., reciprocal) to an equinoxious contour should be applied to a stimulus containing many frequencies to produce an overall magnitude that appropriately combines the contributions from each fr uency. The frequency weightings most commonly employed for whole-body and hand-transmitted vibration are shown in Fig. 10.1 (ISO 2631-1,1997 ISO 5349-1, 2001). The range of frequencies is from 1 to 80 Hz for whole-body vibration, and from 8 to 1250 Hz for vibration entering the hand. A frequency weighting for shocks may also be derived from a biodynamic model (see Dynamic Response Index (DRI) in Sec. 10.3.1). 

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