Group size

Experience should rule here as any formal statistical power analysis would require assumptions as to what a meaningful change would be and as to what the variability of a group of animals (fairly well controlled in normal rats, but much less so in dogs or telemetrized and/or trained animals) on study will be. 

Generally, groups of four rodents or four nonrodents per data point should be adequate, except in the case of a free-standing Irwin screen or functional observational battery (FOB), where many endpoints are assessed in the same animal (with high variability associated with individual endpoints). Here the animals of one sex would be advisable. 

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N = total group size n = sample group size... 

It is obvious, fipom some of the series of substituents in Table 7-11, that the steric constant reflects intuitive notions of group size, and Taft " pointed out close parallels with van der Waals radii. For asymmetrical groups a single van der Waals radius cannot be defined, and the situation is complicated by conformational flexibility. Nevertheless, empirical relationships can be established, and Kutter and Hansch gave Eq. (7-55),... 

Data. Several groups of n replicate measurements of a given property on each of m different samples (for a total of n = l (ni). The group sizes n,- need not be identical. 

Generally, the recrystaUization of S-layer protein into coherent monolayer on phospholipid films was demonstrated to depend on (1) the phase state of the hpid film, (2) the nature of the lipid head group (size, polarity, and charge), and (3) the ionic content and pH of the subphase [122,138] (Table 6). 

Hydrazine is hardiy stabie (see on p.166). Stabiiity increases with the substitution degree and the hydrocarbon group size. The tabie beiow iiiustrates this typicai property. 

With increases in group size and social complexity, and the consequent expansion of diversity in communication, there is presumably selection pressure for unambiguous signals. Over time, evolutionary change may reduce unwanted complexity and act to refine specificity. Whether this results in reliance on the properties of a single component rather than those of the pattern provided by a complex mixture is conjectural. A reasonable expectation is that emitted semiochemical(s) can be reliably produced, and that their contents are acted upon by selection. The improvements in control which can thus be attained are seen in the operation of stereospecificity (Miiller-Schwarze et al, 1976). 

The influence of the group size on the rate of generation of alkyl radicals has been investigated for the same reactions as mentioned in Table 112a> 21 Most information is available on the thermolysis of t-azoalkanes 20 (R1 -R3 = alkyl 28). 

In comparison with the decomposition of taws-azoalkanes 20 a much larger group size effect has been found for the thermolysis rates of a few c/s-azoalkanes 24. Due to the repulsion of the free electron pairs on the two nitrogen atoms and due to steric interaction between the cis oriented alkyl groups cis azoalkanes 24 decom-... 

Hirt H., Hordegen P. and Zeltner E. (2000). Laying hen husbandry group size and use of hen-runs , in Alfoldi T. Lockeretz W. and Niggli U. Proceedings 13th International IFOAM Scientific Conference, Basel, 363. 

Survival is expressed as the number of animals alive / group size. NT not tested. 

As one moves down the group, size (radius) of the atoms increases... 

Group Size. No specific numbers are given, but it does state that a small sample size may lead to failure to observe toxic events. 

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