Indicator of similarity

Structural similarity can sometimes be a very strong indicator of similar function, but does not mean, having similar function necessarily. More important structural similarity can show evolutionary links between proteins whose ancestors may have had similar functions. 

There are many alternative indices of similarity, but Gower s is considered to be fairly general and can be related to several other similarity indices [47]. 

As expected, [TpBut,Me]Zn(i71-0C02Me) [1689 and 1280 cm-1] and [TpButMe]Zn(T71-0C02H) [1675 and 1302 cm-1] exhibit similar r(CO) stretching frequencies, indicative of similar binding modes for the (0C02H) and (0C02Me) ligands. 

A is an anchor compound, one whose ionization ratios are measurable in dilute aqueous add pAbh+ = 100 for p-nitroaniline is used for H0.22 23 Equation (9) is known as the cancellation assumption using it on a series of overlapping weak base indicators of similar type (primary aromatic amines in the case of Ho) leads to Ho values covering a wide addity range according to equation (8), once all the P bh+ values are known. 

In situations with no observed data, one possible means to evaluate status is to use a similar analogous site for which data are available, and to assume that the assessment made from the observed data can be applied validly to both sites. The site for which data are available must have good status according to the WFD. For instance, bodies subject to similar pressures and with similar characteristics could be grouped. It is noteworthy that proximity cannot be taken on its own as an indication of similarity since the features of the catchments, such as climate, topography and ecology, can change abruptly. 

There is doubtful statistical significance in the trend observed in the bondlengths. However, it appears that the similarity in the data for the samples is indicative of similar local structure at all stages of polymer deposition. These values correlate very well with the known coordination number of six and a Ru-N distance of 2.056 A. Q4)... 

A first question is whether a similarity scale is beneficial at all. On the one hand, many users are familiar with statistical reasoning and have to translate an f2 value back to the underlying RMSE scale for better understanding. On the other hand, if the transformation were proven to be scientifically sound and useful, it should not be restricted to f2 but generalized to /) and all other indices of similar structure. 

In contrast to the striking divergences in the carbohydrate parts, respective ceramide moieties resemble those of other cestode glycosphingolipids in so far as sphinganine (d18 0) and 4-hydroxy-sphingoid bases (tl 8 0, t20 0) as well as, in part hydroxylated, fatty acids with 16 to 28 carbon atoms, in particular C26 0 and C28 0, represent predominant ceramide constituents, which might be an indication of similar biosynthetic routes. 

Indications of similar effects are known from catalytic reactions, especially in the case of enzymes, where it is sometimes found that the enzyme gradually loses its activity during its action. Each case must, of... 

Complexes (77) and (78) (see reactions 44 and 45) have been synthesized via reaction of oc-taethylporphyrin (OEPH2) or iV-methyloctaethylporphyrin (iV-MeOEPH) with [Ir(Cl)(CO)3]2. The IR and visible spectra of (77) are quite similar to those of /x-OEP[Rh (CO)2], indicative of similar structures for the two complexes. No evidence for centrosymmetry in (77) was obtained, probably due to the reduction in molecular symmetry by coordination of three CO ligands to each Ir atom.183... 

Diversity patterns are an important feature in the analysis of tropical forest communities. However, a comparison of existing studies is difficult because size and shape of plots, diameter limit of the included individuals, and criteria of site selection may differ considerably (Table 13.5). A simple but helpful measure is the calculation of species per 100 stems (Klinge et al. 1995) (Table 13.5). Another severe problem is that all individuals can not be identified to species level. In all reports a varying percentage of unidentified taxa is present. This reason impedes a calculation of indices of similarity or diversity. The generally observed trends in changing species diversity of Amazonian floodplain forests are as discussed below. 

Although several indices of similarity between data sets have been proposed (Kano et ai, 2001 Kano et al, 2002), the Q statistic is used in C-JIT modeling. The Q statistic is derived from principal component analysis (PCA), which is a tool for data compression and information extraction (Jackson and MudhoUcar, 1979). 

Plate 7. (A) Fluorescence micrograph of the water insoluble droplets formed from a Murchison meteorite extract (67) compared to (B) the fluorescent droplets producedfrom the photolysis residue of the interstellar/precometary ice analog H20 CHsOH NH3 CO (100 50 1 1) at 10 K (40). The similarity between these vesicles is another indication of similarity between the laboratory ice residue and extraterrestrial organics in meteorites. 

In aqueous solution, the rates of acid-catalysed dehydrations increase more rapidly than the stoicheiometric acid concentration . The gradual decrease in the concentration of water results in a shortage of solvating molecules and a concomitant increase in the activity of the acidic species (e.g. H(H.,0)j — H(H.,0)3— H(H20)2 etc.). Medium acidity has to be measured from the extent of ionisation of weak bases and the pioneer attempts were based on nitroaniline indicators (189). The difference in pK between two such indicators of similar basicity was found to be independent of the acidity of the medium, suggesting the ratio, —log (aH+yA/yAn+) was a property of the medium and not the indicator, being subsequently termed 7/ (190) and regarded as the tendency of the medium to protonate a neutral indicator molecule. 

As can be seen from the formula given above, Tanimoto coefficient takes into account only those bits that are ON. Note that the OFF bits do not determine the similarity. In other words, if some molecular features are absent in both molecules, then that is not taken as an indication of similarity between the two. If two molecules have Tanimoto coefficient equal to 1, it indicates that the molecules have identical fingerprint patterns, it however does not indicate the presence of identical molecules, because identical fingerprints do not always designate identical molecules. On the contrary, if the value is zero for dichotomous variables, it indicates complete dissimilarity. The following example will make it clearer ... 

Finally, the similarity of the chemical shifts for the two forms is likely indicative of similar intermolecular arrangements involving the indanyl and difluoroaryl rings confirming the similar packing motifs for the polymorphs. 

The trends in the other bimolecular examples are reasonably understandable. There are fewer orientational constraints in H-atom addition to ethylene than in methyl radical addition the values of ASq are in accord with this interpretation. The hydrogen-transfer reactions of methyl with ethane and ethylene have the same entropy of activation, indicative of similar orientational requirements. The addition of CH3 to CO has a large negative ASq, reflecting the severe geometric constraints necessary for this reaction to be possible. 

A good correlation (a) is indicative of similar chromatographic behavior of two compounds and allows them to be grouped together for the calculation of a distinct phase parameter. 

Many lytic viruses, other than picornaviruses, markedly inhibit host cell protein synthesis during the course of the infectious cycle. None have been investigated to the same extent as poliovirus with respect to the mechanism of this function. However, there are a few preliminary studies which might be interpreted as indications of similar effects on initiation factor activity. 

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