Validity conclusion

The information given above should make it possible in general to predict the usefulness of x-ray methods in problems involving films. In principle, these methods should be useful occasionally when more than one film is present. The problems in such cases are complex rather than complicated. If these methods are applicable to a duplex film, for example, there will be three characteristic lines to be counted, and absorption effects in three regions to be considered. The three counts should, however, contain enough information in many cases to permit the drawing of valid conclusions. 

One excellent study [151] employed intravenous and oral dosing at each of several times postsurgery (1-2 weeks, 6 and 12 months). This design permits valid conclusions about the absorption process. There was a significant reduction after surgery in ampicillin absorption but no change in propylthiouracil absorption. 

To obtain a value for the dimensions of an irregular particle, several measurement approaches can be used Martin s diameter (defined as the length of a line that bisects the particle image), Feret s diameter (or end-to-end measurement, defined as the distance between two tangents on opposite sides of the particle parallel to some fixed direction), and the projected area diameter (defined as the diameter of a circle having the same area as that of the particle observed perpendicular to the surface on which the particle rests). With any technique, a sufficiently large number of particles is required in order to obtain a statistically valid conclusion. This is best accomplished by using a... 

Figure 16 Comparison of the F projections of the multiplicity-edited GHSQC, 60 Hz 1,1-ADEQUATE, the UIC calculated HSQC-1,1-ADEQUATE, and GIC calculated HSQC-1,1-ADEQUATE spectra (power 0.5) of strychnine (1). While Snyder and Bruschweiler have noted52 that signal-to-noise (s/n) measurements of covariance spectra may not be the most viable means of making comparisons, in the present example, the differences are so dramatic that they still allow valid conclusions to be drawn. The C12 (77.6 ppm) resonance provides a convenient s/n comparator. The region from 80 to 100 ppm, which is devoid of responses in the spectrum of strychnine, was used to define the "noise" region for the measurement. There is certainly no question that multiplicity-edited GHSQC is a high-sensitivity experiment as attested by a s/n for the C12/H12 correlation response of 290 1. In comparison, the C12 resonance of the 60 Hz 1,1-ADEQUATE spectrum is a much more modest 22 1. In contrast, the s/n for the C12 resonance in the HSQC-1,1-ADEQUATE spectra calculated using UIC and GIC methods was 293 1 and 257 1, respectively.

This report is the first volume in the series Acute Exposure Guideline Levels for Selected Airborne Chemicals. AEGL documents for four chemicals—aniline, arsine, monomethylhydrazine, and dimethyl hydrazine—are published as an appendix to this report. The subcommittee concludes that the AEGLs developed in those documents are scientifically valid conclusions based on the data reviewed by NAC and are consistent with the NRC guideline reports. AEGL reports for additional chemicals will be presented in subsequent volumes. 

The second reason is that Satchell [78] has shown that in the protonation of m-xylene by catalysts composed of stannic chloride and acetic acid or the three chloroacetic acids as co-catalysts, the rate of reaction is inversely related to the aqueous acidity of these acids. Satchell rightly points out that, since the polymerisations are complicated reactions the rates of which are also affected by the terminating efficiency of the anion derived from the co-catalyst, no valid conclusions can be drawn from such studies about catalytic efficiency in any fundamental sense. He interprets the order of effectiveness of the cocatalysts in terms of the stability of the complexes which they form with the metal halide. 

Every analysis is undertaken for a reason and the results of the analysis should be presented in an unambiguous manner to enable valid conclusions to be drawn. There are certain aspects of reporting analytical results which should be considered. 

Information derived from data-gathering activities serves as the basis for valid conclusions and recommendations. Without effective data gathering, the incident cannot be defined or analyzed effectively. In some cases, gathering data can consume most of the time and resources spent by the investigation team. Some teams report that it can take up to 70 percent of the investigation effort depending on the nature of the occurrence. 

Because of the small number of patients studied in detail, no valid conclusions could be drawn about the precise limits of plasma chlorpromazine concentration for optimum therapeutic effect. Nevertheless, failure to respond to chlorpromazine was shown in one patient to relate to the extremely low plasma concentrations achieved—even by larger than average daily doses of chlorpromazine—whereas in another patient symptoms were aggravated when plasma levels of chlorpromazine were high. 

The randomised part of the Salk Polio Vaccine trial has all the hallmarks of modern day trials randomisation, control group, blinding and it was experiences of these kinds that helped convince researchers that only under these conditions can clear, scientifically valid conclusions be drawn. 

In another study, psychotherapy with and without drug therapy was compared with a no formal psychotherapy control group (421,422 and 423). No valid conclusions can be drawn from this study, however, because there was no adequate control group with respect to medication. Further, the majority of the psychotherapy group received medication and the control group was treated in an entirely different milieu, with many apparently transferred to a chronic facility. 

The methods used must, ideally, permit sampling in a museum, preferably without moving the objects from the display area. The analytical methods should not be particularly time-consuming or expensive because of the volume of data generally required for valid conclusions. These fairly stringent requirements cannot be met in all cases, yet we have attempted to use them as a guide in our studies. 

Without loss of generality we assume that W is indecomposable. Owing to the symmetry property (4.2) or (6.1) this implies that it cannot be reducible to the form (2.7) either. This would not be a valid conclusion if some of the pi could vanish, but in a closed isolated physical system one knows that all states have a non-zero equilibrium probability. 

Naturally the dyeing procedure varies with the type of colour (basic, acid, mordant, substantive). In order, however, that valid conclusions may be drawn, the procedure should be that used industrially, this being usually indicated in the instructions supplied with the colouring matter. 

Several industrial explosions have occurred during the past 40 years which appear to be attributable to this cause, but here has been little recognition of this or of the common features in many of the incidents. Too little investigational work in this area has been published to allow any valid conclusions to be drawn as to the detailed course of the observed reactions. However, it may be more than coincidence that in all the incidents reported, the structures of the nitroaromatic compounds involved were such that o- or p-aci-nitroquinonoid salt species could have been formed under the reaction conditions. Many of these salts are of very limited thermal stability. All of the available (circumstantial) evidence was collected and published [4]. Limited work by... 

Despite the threat to the equilibrium of oxidation/antioxidant defenses, OS was never measured in any of the epidemiological studies, but only in a few cases of acute or chronic diseases. Under these circumstances it is hard to draw any valid conclusions on the effect of antioxidants on health status. 

---