Single description

Create a specification of a system that has multiple interfaces, or many different users, without being forced into a single description. 

A gene expression profile consists of a single description line, starting with > , followed by one or more data lines. The data consist of elements, separated by a space or a new line. Each element consists of a UniGene identifier and an expression value separated by a colon. 

Data storage in REACCS is hierarchical related data are stored separately but also are grouped under a single descriptive category. For example, in the Theilheimer database, the treename is the complete hierarchical name of a piece of data and is composed of three components entity, parent datatypes or category of data, and field datatype. All REACCS databases include VARIATION. VARIATION is usually the highest parent datatype in the reaction hierarchy. VARIATION can be used to store more than one complete set of reaction data with a reaction. To keep track of the data associated with different variations or multiple reactants and products in the same reaction, line numbers are appended to some of the datatypes in a treename. 

This surv cy included individuals 12 years of age or older. Personal and self-administered interview s were completed with 67,500 respondents. As it was a household survey, people such as military personnel in military installations, individuals in long-term hospitals, and prisoners were excluded from the sample. As a result, the data cannot be viewed as completely representative of everyone in the 50 states. Nevertheless, the National Survey on Drug Use and Health provides the best single description of frequency and quantity of drug use among a broad age range of people in U.S. society. 

The redox status of an aqueous system is described by the concentrations of the oxidized and reduced species of all system components. Redox systems, generally not at equilibrium as the result of kinetically slow redox reactions, are poorly characterized by intensity factors (Ej or pE) alone. Capacity factors, which reflect the total concentration of relevant species, are conservative parameters that can be meaningful guides to the redox status of aqueous systems. Oxidative capacity (OXC) is defined as a conservative quantity that incorporates a comprehensive chemical analysis of the redox couples of an aqueous system into a single descriptive parameter. OXC classifies aqueous systems in terms of well-defined geochemical and microbial parameters (e.g., oxic, sulfidic). Examples of model and actual groundwater systems are discussed to illustrate the concept. A redox titration model is another tool that is useful in describing a redox system as it approaches an equilibrium state. 

A major factor in the uncertainties of the redox status of an aqueous system is the time dependency of redox reactions. The fact that the rates of electron transfer are relatively slow and that the electrochemical response of an electrode is also time dependent makes the determination of pE or Ej undependable and of little general value as a single master variable. We wish to define a conservative quantity that will incorporate a comprehensive chemical analysis of the redox couples of an aqueous system into a single descriptive parameter for that redox system. This capacity factor is called the oxidative capacity (OXC) of a redox system and represents the total number of transferable electrons. This concept allows us to classify aqueous redox systems by a conservative quantity as is done with alkalinity and acidity measurements. This parameter will also allow investigators to better characterize the redox status of an aqueous system than is possible with a knowledge of the redox potential alone. 

No single description or definition adequately covers all lubricants or lubrication processes. For example, we have seen that a fluid can function as a lubricant by virtue of its viscosity as a liquid. We have also seen that a monomolecular film of stearic acid deposited on a metal surface acts as a lubricant and dramatically reduces the coefficient of friction. A polymeric substance such as polymethylmethacrylate when dissolved in an oil will increase its viscosity and improve its loadcarrying performance in the hydrodynamic lubrication process. Stearic acid dissolved in a carrier oil can effect a strong reduction in the coefficient of friction for metal rubbed against metal. 

Because the various flow patterns shown in Fig. 14.3 are so different from each other, it is unlikely that there will ever be a cornpletely successful single description of the friction effect and holdup, of yertical, gas-liquid flows comparable, e.g., to the friction factor plot for pipe flow. The various flow forms are so different physically that they cannot be expected to obey the same mathematical relationships. Several such overall correlations are available, e.g., that of Hughmark and Pressburg [3], in which for a variety of fluids they correlated liquid holdup 1 - with the group... 

The single description of statics and dynamics made it also possible to extend the interpretations of the notions of state and trajectory fxmctions. The work in an infinitesimal period of time in the vicinity of equilibrium point was interpreted by Lagrange as a function of state. Representation of the trajectory in the form of a continuous sequence of equilibrium states makes it possible to interpret the work as a virtual (possible) function of rest during the entire modeled process. 

The best resonance form, and therefore the best single description of the molecule, is the diene structure we conventionally write. This structure has one more bond than the others and involves no charge separation. Thus, it wins by almost all of our criteria for estimating the relative energies of resonance forms (p. 372). Nevertheless, the three other resonance forms in Figure 12.15 show that there is some double-bond character to the C(2)—C(3) bond. 

Template models - A template model is a single description that describes a class of behaviors. As an example, a single template can be used to describe a family of adders of different size. Templates are similar to high-level module generation, and are therefore very useful in describing libraries of hardware operators at a high level. 

Although many of the structures of interest to us have only one central atom, VSEPR theory can also be applied to molecules or polyatomic anions with more than one central atom. In such cases, the geometric distribution of terminal atoms around each central atom must be determined and the results then combined into a single description of the molecular shape. We use this idea in Example 10-12. 

One of the many attractive features of bond valence theory is that it provides a single description of a bond that spans the whole range of bond types with valences ranging upwards from zero. Because bonds form a continuum, the theory makes no distinction between ionic and covalent bonds aU bonds obey the same set of rules. Yet the use of the terms ionic and covalent is so widespread that their usefulness cannot be questioned. Some might define covalent bonds as those that share bonding electrons and ionic bonds as those formed by the electrostatic... 

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