Inadequate Sampling

The District of Columbia was concerned that the open-air arsenical war gas testing during 1917 and 1918 deposited an arsenic layer over the site. There is new information that a layer of 75 ppm arsenic exists at an adjacent site but about a mile from the testing locations. This layer exists in a narrow horizon, 1 ft below the surface, suggesting that it was deposited 

Because of this new information, the District was concerned that the Army employed no technology, such as x-ray fluorescence, to ascertain that its soil samples were taken at this precise horizon. Although most samples were taken between 6 in. and 3 ft in an attempt to test the 1918 surface, they could not be certain if the high readings for metals were in the horizon and the low readings were from samples inadvertently taken just above or below the horizon and therefore misleading. 

The District of Columbia was concerned over new information from the Final Report Conducted on President s Residence by Environmental, Inc., dated August 6,1996, that an arsenic level of 1200 ppm was found as well as other high arsenic readings. In the excavation where five construction workers were overcome on May 27, 1992— which is next door to the 1200 ppm sample—a white granular layer was observed that may be inorganic arsenic. 

Thallium is found in significant amounts. One unit at the Experiment Station developed explosives and fuses. Thallium azide, thallium nitride, and thallium fulminate are shock sensitive explosives and emit poisonous fumes. It would have been an ideal subject of experimentation. Thallium as high as 58.52 ppm was found. The oral LDjg for rats is 16 mg/kg, and the LDjo for children is 8 mg/kg. LDjg is the lethal dose at which 50 percent of the population dies. 

Adding to the District s concern was the fact that there was a wide deviation between the content of arsenic and other metals such as beryllium, even within the same POI. For arsenic, the overall range is from 241 ppm to an undetectable level. With a wind-driven plume, such a variance would be proportional to the distance from the source, but that is not the case here. The high and low readings carry no logical significance except that sampling may have missed the thin arsenic layer. 

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The dominant supply of U to the oceans is from the continents by river runoff Palmer and Edmond (1993) measured dissolved U concentrations in a number of rivers and summarized existing literature to arrive at a total flux close to that of Cochran (1992) of 11 X 10 g/year. This flux is uncertain by about 35% due to inadequate sampling of rivers with large seasonal cycles (Palmer and Edmond 1993). 

At short distances, approximately equal to the excluded volume diameter, effective pair forces obtained from force matching exhibit unphysically large fluctuations. This is largely due to inadequate sampling of configurations at short distances in... 

The other possible sources of error are primary and secondary extinction effects, inadequate sample thickness, and finally, instrument-related errors. These issues are addressed in the literature [1]. 

It has been mentioned that perhaps the greatest limitation to the precision of free energy calculations to date has been the often-inadequate sampling of a representative set of configurations of the system. Increases in computer power of course increase the radius of convergence of such calculations. Such increases come not only from the Moore s Law improvements in hardware, but also from algorithmic... 

Using a biased or inadequate sample of data as evidence... 

Go ahead with the study as is, with the awareness that a potentially inadequate sample size may be enrolled and followed to a satisfactory, evaluable end point. (In certain specialties this may be acceptable, though looked on less favorably as time goes on.)... 

Sample sizes for randomized controlled trials in neurology may need to be large, either because treatment effects are relatively small or because the progression of disease is slow. Table 18.3 shows the effect of sample size on the reliability of the result of a trial of a hypothetical neurological treatment that is assumed to reduce the risk of a poor outcome by 20%, from 10% to 8%. The risk of getting the wrong result when a trial has an inadequate sample size is illustrated in Fig. 18.1. In this trial, there was considerable variability in the apparent effect of treatment until several hundred patients had been randomized. If the trial had been small, misleading trends in treatment effect could easily have been reported. 

The issue of inadequate sampling time is exemplified by monoclonal antibodies. As shown in Table 32.12/ the Vi and Vss are similar and are similar in size to a vascular space of 2-3 L/m. It is also important to note that for the most part/ in the studies submitted to support New Drug Application (NDA) approval/ Vgs was determined with methods assuming linear/ first-order kineticS/ and clearly this is not the case for the majority of the monoclonal antibodies currently marketed/ such as cetuximab (Erbitux). In fact/ the use of noncompartmental methods to describe the pharmacokinetics of mABs oversimplifies their complex properties. 

In order to evaluate cirrhosis in terms of morphology, certain requirements have to be fulfilled. Occasional diagnostic uncertainty or divergent classification may arise from the fact that the biopsy material is insufficient and therefore not representative. This, in turn, is probably due to the fact that the techniques used in obtaining these inadequate samples were faulty or unsuitable, (s. pp 160, 161, 408, 726)... 

It must be noted that the invariance to rotation of G-WHIM descriptors, i.e. the independence of any molecular alignment rule, is obtained if the grid points are dense enough. In fact, a too sparse distribution of grid points represents an inadequate sampling of the ideal scalar field and is not able to guarantee that the calculated scalar field is representative of the ideal scalar field in such a way as to preserve rotational invariance. 

The potential for inadequate sample inventory management in prescribers offices and inappropriate storage of products by pharmaceutical representatives raises con-... 

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