True factors

The procedure is schematically shown in Fig. 34.29. Equation (34.10) represents a homogeneous system of equations with a trivial solution r, = 0. Because component / is absent in the concentration vector, this component does not contribute to the matrix T °. As a consequence the rank of T is one less than its number of rows. A non-trivial solution therefore can be calculated. The value of one element of r, is arbitrarily chosen and the other elements are calculated by a simple regression [17]. Because the solution depends on the initially chosen value, the size (scale) of the true factors remains undetermined. By repeating this procedure for all columns c, (t = 1 to p), one obtains all columns of R, the entire rotation matrix. 

A true factor exerts its effect directly on the system and is correctly identified as doing so. A masquerading factor also exerts its effect directly on the system but is incorrectly assigned some other identity. 

But time is not the true factor sugar content of the fruit is the true factor, and it is masquerading as time. The masquerade is successful because of the high correlation between time of year and sugar content. 

Occasionally, a response from a system will act as a true factor to the same system, a phenomenon that is generally referred to as feedback. (This is not the same as the situation of masquerading factors.) Feedback is often classified as positive if it enhances the response being returned as a factor, or negative if it diminishes the response. 

Will variables that are true factors, but are not identified as factors always produce random and erratic behavior in a system (see Table 1.1) Under what conditions might they not ... 

The diameter of any stain is always larger than that of the impinging droplet, the relationship between the two diameters is referred to as the spread factor. The spread factor is an empirical value which must be a determined anew for each formulation and each target surface. The droplet size data in the present study were derived using an assumed spread factor on fir foliage of 2.5. Recent measurements (8) using a mono-disperse droplet generator have shown the true factor to be 2.66. 

Using the above formula. Table 11.1 can be calculated. It can be seen that the true factors of synergism (P OSj are considerably smaller than those calculated conventionally,... 

For nongenotoxic chemicals, risk assessment is based on the concept of threshold doses, below which no adverse effect results from exposure. From human or experimental animal data, one tries to establish the no observable adverse effect level (NOAEL) and the lowest observed adverse effect level (LOAEL). In order to establish safe levels of exposure to potentially toxic agents, the NOAEL is divided by a safety factor (often named uncertainty factor). When the risk assessment is based on data from experimental animals, a default safety factor of 100 is usually applied. The safety factor constitutes a factor of 10 for potential differences in susceptibility between animals and man, and another factor of 10 for interindividual differences among humans. The factors are combinations of differences in toxicokinetics and toxicodynamics, both in animals and man. If true factors are known, the size of the safety factor may be changed accordingly. When risk assessment is based on human data, a safety factor of 10 is applied in most cases, for instance, for food additives. However, for natural toxins in food, smaller factors are usually applied. This is a risk management decision, often based on information on the absence of adverse health effects at intake levels close to the estimated LOAELs. 

Although a modulus value is more useful in pavement design, most traditional specifications and QA/QC measures are based on soil density. Soil modulus is a true factor but is dependent on many factors and the reported modulus is associated with a certain stress level, strain level, rate of loading and water content (Briaud and Seo 2003). There is no evidence for a direct correlation between soil modulus and density (Briaud and Seo 2003) and therefore a conversion of specifications to a modulus value would therefore be problematic. 

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