Uncertainty endogenous

While the angiotensins promote release of aldosterone, the atrial natriuretic hormoner aa cc inhibits release. This group of 21- to 33-residue polypeptides, secreted by cells of the atria (auricles) of the heart, also inhibits release of renin and promotes secretion of both Na+ and water. Thus, they antagonize the action of aldosterone, which promotes Na+ retention. However, there is uncertainty as to the significance of these peptides. The following metabolite of y-tocopherol (Fig. 15-24) has been isolated from urine and is proposed as a new endogenous natriuretic factor.dd... 

Demonstration of selectivity and specificity of an assay for a biomarker must be considered in the context of whether the assay is a definitive quantitative assay or a relative quantitative assay (see Section 1.2). It can be difficult to show absolute specificity and selectivity for a relative assay due to the uncertainty of the exact species being measured and unknown components of the matrix. At a minimum, reproducible measurements of endogenous samples with and without spiking of the reference analyte should be demonstrated. On the other hand, likely truncated forms of a well-characterized biomarker measured by a definitive quantitative assay can be tested for specificity, as in the following example. 

In conclusion, while exogenous ROI such as H2O2 do not seem to affect NF-kB activation in neutrophils, some uncertainty subsists concerning whether endogenous ROI can affect the ability of neutrophils to activate NF-kB. Clearly, further work is required to definitively settle the issue. 

Table 2. Comparison of the apparent dissociation constants (Kq ) for MKq and LIQ0 in wiid-type RCs and in RCs mutagenized at Trp °- Endogenous quinone was removed from wiid-type and 1-ipM250 Pf,g pQg ijy treatment with 4% LDAO/10 mM o-phenanthroiine. RC concentration was 0.75 pM. Kq was caiculated by a least-squares fit to Scatchard plots of the data. The uncertainty in the value of Kq is 15%.

Terrazas-Moreno, S., Grossmann, I.E., Wassick, J.M., Bury, S.J., and Akiya, N. (2012) An efficient method for optimal design of large-scale integrated chemical production sites with endogenous uncertainty. Comput. Chem. Eng., 37, 89-103. 

Based on the above literature review, the following conceptual model (Figure 1) can be drawn. The model has five constructs asset specificity, uncertainty, vertical coordination, quality management practices and firm performance. Firm performance will be measured by tangible and intangible variables. They are used as latent dependent (endogenous) variables. The other four variables will be used as latent-independent (exogenous) variables. For operationalization, each construct contains a set of indicators (See Appendix). 

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