Lack of precision

The chart consists of a central line and two pairs of limit lines or simply of a central line and one pair of control limits. By plotting a sequence of points in order, a continuous record of the quality characteristic is made available. Trends in data or sudden lack of precision can be made evident so that the causes may be sought. 

Thin-layer chromatography (76,77) has been used for the estimation of the amounts of dimer, trimer, and monomer ia methyl esters. Both this method and paper chromatography are characterized by lack of precision (78,79) (see Chromatography). 

The widely observed lack of precise correlations among properties that chemical experience leads us to believe are somehow related to polarity has two important meanings First, it tells us that no single property may be taken as a generally applicable measure of polarity. Second, it conveys the message that some combination of the properties may capture the essence of what we mean by polarity. 

Many project managers find it realistic to estimate time intervals as a range rather than as a precise amount. Another way to deal with the lack of precision in estimating time is to use a commonly accepted formula for that task. Or, if you are working with a mathematical model, you can determine the probability of the work being completed within the estimated time by calculating a standard deviation of the time estimate. 

In summary, main structures involved in the action of psychostimulants can be divided into cortical (mainly prefrontal cortex) and subcortical (basal ganglia and related structures, LC and cerebellum) ones. Figure 1 gives a schematic overview of the connections between these structures, omitting the cerebellum due to lack of precise information. 

One significant drawback in all the previously described experiments in the lack of precise knowledge abont the tip, particnlarly with regard to shape and chemical nature on the... 

Twenty-three kinetics have been carried out at 25°C for pH values from 8.25 to 11.25. The rate constant, calculated as the average of all the ks, was of 27.2 9.0 mol 1 min. The pH correction according to equation (2) was not perfect, as there was a tendency to obtain higher k values at lower pH values. However, this was specially true for extreme vdues of our pH range, where the buffer capacity of ethanolamine was limited (higher pHs) or the reaction proceeded very slowly (low pHs), impairing the precision of the data. Another factor that might explain the dispersion of the data is lack of precision of pH measurement (no better than 0.02 pH units). 

The scale-up from a small to a large plasma reactor system requires only linear extrapolations of power and gas flow rates. However, in practice, the change in reactor geometry may result in effects on plasma chemistry or physics that were unexpected, due to a lack of precise knowledge of the process. Fine tuning, or even coarse readjustment, is needed, and is mostly done empirically. 

Recently a decreased level of CE activity has been noticed with a shift of attention towards other separation techniques such as electrochromatography. CE is apparently not more frequently used partly because of early instrumental problems associated with lower sensitivity, sample injection, and lack of precision and reliability compared with HPLC. CE has slumped in many application areas with relatively few accepted routine methods and few manufacturers in the market place. While the slow acceptance of electrokinetic separations in polymer analysis has been attributed to conservatism [905], it is more likely that as yet no unique information has been generated in this area or eventually only the same information has been gathered in a more efficient manner than by conventional means. The applications of CE have recently been reviewed [949,950] metal ion determination by CE was specifically addressed by Pacakova et al. [951]. 

Chocolate milk samples prepared from sweetened cocoa powders averaged 58 mg per serving of theobromine and 5 mg per serving of caffeine.28 Analysis of a "home-style" recipe resulted in higher methylxanthine values — 94 mg theobromine and 10 mg caffeine per serving. However, the authors noted that this recipe also had a stronger chocolate flavor. The lower values reported by Zoumas et al. and Blauch and Tarka compared to others was attributed to the inability of older methods to separate theobromine and caffeine, and the lack of precision and accuracy of the older methods. A compendium of theobromine and caffeine values reported for chocolate beverages from both published and unpublished studies has been compiled in Table 8. 

The only problem with this method is observed for weak reflections where (+)/(-) count-rates are similar (i.e. R 1). The (+)/(-) optimised counting-time proportions must be 50%/50%, but with low count-rates, we have observed that the lack of precision may lead to proportions which are not optimum (e.g. 47%/53%). The same behaviour has been observed for peak to background proportions. In fact, when measuring a flipping ratio in many steps, we observe oscillations of the time proportions which slow the decrease of the standard deviation. Of course, these time variations have no sense, and one should calculate the variances of the optimised counting-times (Equations (16)) to avoid such spurious fluctuations ... 

This method can, in principle, be used to determine the transport characteristics of drugs dissolved or suspended in pharmaceutical gels. A potential problem with this method is the possibility for the gel to dissolve into the aqueous phase, with resulting disruption of the free boundary. These changing experimental conditions would lead to lack of precision for the experimental results and difficulty in interpreting them. 

A quantitative term to describe the (lack of) precision of an analytical procedure (e.g. by standard deviation). 

Lack of precision. The complex nature of any biological system, be it an entire animal or individual cell, often results in the responses observed being influenced by factors such as metabolic status of individual cells, or (in the case of whole animals) subclinical infections, stress levels induced by human handling, etc. 

The underlying cause of this accident was the lack of precise reaction decomposition data. With good data, engineers can design safeguards to absolutely prevent accidental heat-up. 

Many requirements changes are actually the result of initial lack of precision. 

The lack of precise measurements of environmentally relevant chemical rate constants limits the number of quantitative evaluations of the importance of complex dynamics on uptake fluxes. Nonetheless, examples involving bicarbon-ate-CC>2 conversion [69,88] and trace metal complexation [8,46,325] have been examined theoretically in the literature. For example, comparison of the diffu-sional and reactional timescale allowed Riebesell and collaborators [69,88] to show that bicarbonate conversion to CO2 did not generally enhance the... 

There is no major advance which can be reported in our knowledge of protopectinases. The possibility of the existence of a protopectinase different from PG seems now somewhat more remote than it was ten years ago. As stated above, the trend in thinking about protopectin is definitely in the direction that protopectin is not a specific cellulose-pectinic acid compound but pectinic acid which is insoluble either on account of large molecular size or due to the effect of polyvalent cations or both. In this sense there is really no need to assume the existence of a separate protopectinase. There is little doubt that this uncertainty is in a large degree attributable to the lack of precise knowledge of protopectin. 

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