Inference ambiguity

Kluge, A.G., Three-taxon transformation in phylogenetic inference ambiguity and distortion as regards explanatory power, Cladistics, 9, 246-259, 1993. 

Determination of degradation by measurement of loss may be ambiguous since this fails to take into account transformation to metabolites. At field sites, loss by other processes such as volatilization is difficult to assess, but may be inferred, for example, from low concentrations of the more volatile alkylnaphthalenes. The use of stable isotopes is discussed in Chapter 13. 

Perhaps the most revolutionary development has been the application of on-line mass spectroscopic detection for compositional analysis. Polymer composition can be inferred from column retention time or from viscometric and other indirect detection methods, but mass spectroscopy has reduced much of the ambiguity associated with that process. Quantitation of end groups and of co-polymer composition can now be accomplished directly through mass spectroscopy. Mass spectroscopy is particularly well suited as an on-line GPC technique, since common GPC solvents interfere with other on-line detectors, including UV-VIS absorbance, nuclear magnetic resonance and infrared spectroscopic detectors. By contrast, common GPC solvents are readily adaptable to mass spectroscopic interfaces. No detection technique offers a combination of universality of analyte detection, specificity of information, and ease of use comparable to that of mass spectroscopy. 

The indicators were not tested for their suitability for taxometric analyses, but the authors reported that the composite was reasonably reliable (alpha =. 76). Whisman and Pinto performed a MAMBAC analysis, and both curves had a clear peak (although it was substantially shifted to the right), indicating a taxon with the base rate of about. 25. The actual base rate estimate was. 44, but the inconsistency between the shape and the estimate was probably due to high nuisance correlations. The authors, however, concluded that the inconsistency indicated dimensionality and did not pursue the issue further. It appears that this conclusion is mistaken. Although the plots are somewhat ambiguous, and there are only two of them, no firm inference can be drawn from this study. 

Not having been so expressed or particularized, the most reasonable inference would be that the word white, ethnologically speaking, was intended to be applied in its popular sense to denote at least the members of the white or Caucasian race of people. If there be ambiguity and doubt, it is better to resolve that doubt in favor of the Caucasian possessed of the highest qualities which go to make an excellent citizen, as the applicant appears to be. .. If the word white in its popular sense is of too broad a signification, as applied to persons deemed suitable to become citizens of the United States, the remedy is easily at hand by an amendment of the law.39... 

In Tables A.1 through A.3, all Ksv, values were converted to mL mL units where applicable. In the literature sources where the units were not explicitly mentioned, these were inferred from the model equations used. To avoid possible ambiguity in the future, authors are urged to specify the units of their reported Ks values. 

In the early days of stable ion chemistry, the experimental measurements of parameters such as NMR chemical shifts and IR frequencies were mainly descriptive, with the structures of the carbocations being inferred from such measurements. While in cases such as the tert-butyl cation there could be no doubt of the namre of the intermediate, in many cases, such as the 2-butyl cation and the nonclassical ions, ambiguity existed. A major advance in reliably resolving such uncertainties... 

Because so much of the behavior of suspensions is determined or modified by charge associated with the solid phases, ZPC may be inferred from a wide variety of experiments involving pH as a master variable. For example, coagulation and sedimentation rates are maximum at the ZPC, and anion and cation exchange capacities (measured with nonspecific, symmetrical electrolytes) are equal and minimum at the ZPC. More direct and less ambiguous are electrophoresis and streaming potential, in any of their modifications. One can estimate the IEP(s) by measuring adsorption of H+ and OH" if one is certain that no specific adsorption of other species occurs. 

Usually, owing to insolubility or unacceptable buffers, large protein fragments are not beneficially analyzed by ESI-MS. However, the identity of stable domains of protein molecules can still be inferred from the accurate mass measurements of the smaller polypeptide fragments obtained from limited proteolysis. This provides a basis for resolving the compact domains for proteins in situations where matrix-assisted laser desorption ionization (MALDI) data are ambiguous and ESI-MS of the large protein may be precluded. 

Observe that this system continues to assume that both the number and the location of hydrogen atoms can be inferred, rather than having to be named. This is a potential source of ambiguity that will be revisited shortly. 

The reliable estimation of source impact on receptor conditions is difficult from theory because of undetermined uncertainties. Inference from comparison between emissions and measurements offers an alternative to calculations. Measurements in the East have yielded ambiguous source-receptor relationships. However, evidence suggests that recent changes in sulfate deposition in the West are linked with relatively large changes in SO emissions from non-... 

It is possible that a cause-and-effect relationship between molecules comprising the asphaltene fraction and difficulty in processing does not exist and that these relationships are largely fortuitous in that the chemistry involved in asphaltenes isolation is only secondarily related to chemistry of processing. If such is the case, much of the ambiguity surrounding asphaltenes derives from the incorrect assumptions about the chemistry of complex hydrocarbon mixtures inferred from empirical correlations. 

In the chromophore-quencher system (1) a ferrocenyl unit is connected to a Ru(tpy)2 + unit via a p-phenylene-acetylene spacer [141]. The weak emission of the Ru(tpy)2 chromophore is completely quenched in the dyad [142]. For this system, an EnT mechanism could be inferred by analogy with the behavior of related bimolecular systems [140], but PET followed by fast back electron transfer cannot be ruled out. This mechanistic ambiguity is common to most studies on related chro-mophore-ferrocene dyads [143-146]. 

Bending moduli can in principle be obtained for two types of systems (i) extended, flat surfaces or interfaces, the subject matter of this section, and (ii) surfaces that are already strongly curved, and for which y is zero or extremely low, such as in vesicles or micro-emulsions. For instance such moduli can be inferred from shape fluctuations, from the Kerr effect (sec. 1.7.14] or from polydispersity using some scattering technique. We repeat that this type of measurement is often ambiguous because the bending contributions to the Helmholtz energy can only be estimated when all other contributions are accurately known. 

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