Conceptual Ambiguities

Despite the success of the disorder model concerning the interpretation of data on the temperature and field dependence of the mobility, one has to recognize that the temperature regime available for data analysis is quite restricted. Therefore it is often difficult to decide if a In p vs or rather a In p vs representation is more appropriate. This ambiguity is an inherent conceptual problem because in organic semiconductors there is, inevitably, a superposition of disorder and polaron effects whose mutual contributions depend on the kind of material. A few representative studies may suffice to illustrate the intricacies involved when analyzing experimental results. They deal with polyfluorene copolymers, arylamine-containing polyfluorene copolymers, and c-bonded polysilanes. 

When we deal with the kinetics of hydride reactions we have to be aware that hydride thermodynamics cannot be properly formulated without taking into account the (relative) immobility of the metal component. This immobility can sometimes render the interpretation of the experimental reaction kinetics ambiguous. With this difficulty in mind, let us outline concepts which describe the kinetics of hydride formation and decomposition. An extensive account, including a first order phenomenological treatment, has been given by [P.S. Rudman (1983)]. The conceptual framework for a more rigorous discussion is found in, for example, [G. B. Stephenson (1988)]. 

When the hydrogen ion is considered to be attached to the rightmost end of the Rhodonine ion, Rhodonine will appear to be an alcohol and respond to simple chemical tests almost identically to Retinol. When the hydrogen ion is considered to be attached to C5, Rhodonine will appear to be an aldehyde and respond to simple chemical tests almost identically to retinaldehyde. The chemical ambiguity in the properties of the Rhodonines due to this resonance condition is the principle practical reason for the confusion in the literature concerning the chemical properties of the chromophores of vision. The principal conceptual reason is the prior failure of the community to recognize the existence of the resonant form of the retinoids, the Rhodonines. 

It might appear that the related measurement of the electron affinity of the C4H4 radical cation would be equally useful. However, one cannot expect simply dumping an electron into a radical cation from a neutral molecule M to proceed without complication or ambiguity. That is, the seemingly simple electron transfer reaction (23) has conceptual... 

The conceptual status of social relations and of science, therefore, is somewhat ambiguous. They satisfy some of the theoretical constraints on the productive forces, but not others. This is not to say that they constitute fundamental difficulties in Marx s project. Rather, they represent substantive, medium-sized problems of the kind that will arise in any comprehensive theory of social change. A deeper flaw in the theory arises in Marx s treatment of population. In accordance with the mercantilist... 

In homogeneous systems such as solutions molecular environments and their role in determining the fate of photo-excited states are not complicated at least conceptually. On the other hand, in the heterogeneous systems such as interfaces, biological polymers, cells etc., even the definition of molecular environments is ambiguous and we are still far from the true understanding of them. 

Liu, H. F., S. B. Johnson, and C. Friedman. 2002. Automatic resolution of ambiguous terms based on machine learning and conceptual relations in the UMLS. J Am Med Inform Assn 9 621-36. 

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