History , classifying data

Model equations can be augmented with expressions accounting for covariates such as subject age, sex, weight, disease state, therapy history, and lifestyle (smoker or nonsmoker, IV drug user or not, therapy compliance, and others). If sufficient data exist, the parameters of these augmented models (or a distribution of the parameters consistent with the data) may be determined. Multiple simulations for prospective experiments or trials, with different parameter values generated from the distributions, can then be used to predict a range of outcomes and the related likelihood of each outcome. Such dose-exposure, exposure-response, or dose-response models can be classified as steady state, stochastic, of low to moderate complexity, predictive, and quantitative. A case study is described in Section 22.6. 

The US Food and Drug Administration classifies caffeine as generally recognized as safe (GRAS). This designation means that there are sufficient data and history of use to indicate that caffeine is safe to consume in the amounts commonly found in foods and beverages. The FDA allows caffeine to be added to cola drinks. 

The amount of adsorbate that can be held depends on the concentration or partial pressure and temperature, on the chemical nature of the fluid, and on the nature, specific surface, method of preparation, and regeneration history of the solid. For single adsorbable components of gases, the relations between amount adsorbed and the partial pressure have been classified into the six types shown in Figure 15.2. Many common systems conform to Type I, for example, some of the curves of Figure 15.3. Adsorption data are not highly reproducible because small contents of impurities and the history of the adsorbent have strong influences on their behavior. 

One possibility is to classify the methods used in the various steps of the analytical process (see also Section 1.5). Note that the analytical process usually starts with the definition or selection of the matter to be investigated. Here it is very important to realize that every sample or object of investigation has a history. Because this history may cause severe systematic errors, THIERS [1957] explains Unless the complete history of any sample is known with certainty, the analyst is well advised not to spend his time in analyzing it. Clearly, in such circumstances one should be extremely cautious about drawing conclusions from chemometric interpretations even where data are available. 

Classification may thus be viewed as a process by which a structure can be detected from the chaos in the data that are presented. In chemistry and other sciences the ideal form of the classification process is the transformation of experimental or observational data into scientific laws. Throughout the history of chemistry many empirical laws have been discovered by analyzing and classifying experimental data. In general, classification needs to be performed on newer kinds of objects or on novel... 

In 2003, astronomers announced that data and observations indicated one particular crater might well be classified as the youngest crater thus far discovered. The crater, formed in 1953 by an asteroid impact, is the only known lunar crater to have been formed during recorded human history. New and more powerful telescopes, along with orbiting satellite photos now allow examination of the impact site and astronomers observed indications of a fresh crater in the impact zone (i.e., the area corresponding to the impact flash observed in 1953). 

Scientific work can be classified into two general categories collecting and collating data, and drawing conclusions and building theories based on those data. Neither activity can be conducted without the other, and either, in and of itself, is incomplete. One of the great data collectors and collators in the history of astronomy was Annie Jump Cannon, who came to astronomy somewhat late in life, at the age of 31. 

Some reports are not easily found and have undoubtedly been overlooked. A few are still classified and cannot be quoted or referenced directly. However, the classified documents contain no significant data that are not also found in the unclassified reports. Finally, this is intended to be a history of a program, not a scientific review of this literature or a description of the clinical effects of nerve agents in humans, reports of which can be found elsewhere (Sidell, 1992). 

For the purpose of this study, we used the SpaceTrak database (Ref. 2). This database is used by most of the world s laimch providers, satellite insurers, sateUite operators and manufacturers and provides extensive data on sateUite on-orbit failure and anomalies, as weU as laimch histories since 1957. While this database is not complete (since some classified sateUites for example may not have their failures reported, and since sateUite operators may not report aU anomalies, especially, the ones that can be recovered from in a timely manner), it is considered the most authoritative database in the space industry with detailed information and failure data for over 6400 spacecraft. More details about this database can be found in Reference 2. 

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