Natural variability

Under most conditions, the sign of V" (q ) in (A3.8.17) is negative. In such cases, the centroid variable naturally appears in the theory 39, and the equation for the quantum thennal rate constant from (A3.8.14) -(A3.8.17) is tlien given by [39]... 

Having explained the origin of the adaptable (condition-dependent) character of molecular properhes, we now turn to illustrahons of this phenomenon. Indeed, stahng the variable nature of molecular properhes is not sufficient to appreciate its significance in drug design and SAR studies. 

In summaiy, periphyton are present in all lakes, easy to sample, and would respond rapidly to changes in the abundance of MeHg. Periphyton are sometimes eaten directly by fish. The diverse, complex, and variable nature of the periphyton community, however, would complicate interpretation of mercury concentrations in periphyton in a monitoring program. 

The overall compositions of films 2 and 4 was such that homogeneous alloys were not expected, and the X-ray diffraction peaks showed evidence of phase-separation with two maxima corresponding to the compositions recorded in column 8, Table II. When palladium was deposited on top (and the film was rather light) then the apparent surface composition after annealing was 10% Rh and X-ray diffraction indicated a phase also containing 10% Rh (film 2). This convenient result was not observed when the order of deposition was reversed (film 4). These differences between apparent surface composition and the overall composition of the homogeneous alloy (or one of the phases in the miscibility gap) are discussed in Moss and Gibbens (34), with further examples. The main point to be made here is the rather variable nature of the surface composition compared with that expected, due to the operation of a number of factors. 

Proarrhythmia can be difficult to diagnose because of the variable nature of underlying arrhythmias. 

The function of the metal site in the oxygen-dependent radical enzymes galactose oxidase, amine oxidases, ribonucleotide reductase, and cytochrome c oxidase is inter alia to bind 02 in their reduced forms and undergo the appropriate redox chemistry to generate a metal-bound, activated oxygen species of variable nature. 

Note that the measurements and estimates include both measured state variables and measured input variables. The inclusion of the input variables among those to be estimated establishes the error-in-variable nature of the data reconciliation problem. 

Note 1 The use of this equation with the relative molecular mass (molecular weight) is recommended, rather than with molar mass (which has the dimension of mass divided by amount of substance), since in the latter case the constant K assumes awkward and variable dimensions owing to the fractional and variable nature of the exponent a. 

A weakness in the whole area of alternative therapies is that one cannot determine, even on a statistical basis, either the benefits or harms that the treatment may cause. It is this lack of valid knowledge about the intervention s effects that separates alternative methods from scientific medicine. Furthermore, because of the variable natural course of... 

Because of the highly variable nature of precipitation events, quantitatively estimating wet deposition of pollutants is difficult. In addition to meteorological factors, parameters such as the solubility of the pollutant in ice, snow, and rain and how this varies with temperature and pH, the size of the water droplets, and the number present must also be considered for example, snow may scavenge some species more efficiently than rain. 

The highly variable nature of signaling pathways is also expressed by the fact that different receptors and signaling pathways can induce the same biochemical reaction in a cell. This is exemplified by the release of Ca, which can be regulated via different signaling pathways (see chapters 5-7). 

In view of the conflicting indications provided by different measurements, it seems likely that the bond type in chemisorbed hydrogen is actually of an intermediate and variable nature, approaching essentially... 

J. Black s investigation 3 of 1756 is the first contribution to the chemistry of the carbonates of ammonia, and he pointed out the chemical difference between the aqua ammonia and the solid carbonate of commerce. J. Priestley also, in 1774, dwelt on the same subject. T. Bergmann analysed the commercial carbonate in 1774 H. Davy emphasized the variable nature of the compounds of carbon dioxide and ammonia in 1799 while C. L. Berthollet (1806) and J. Dalton (1819) demonstrated that there are several different carbonates of ammonia. In his paper On the combinations of carbonic anhydride with ammonia and water (1870), E. Divers showed that there are at least three well-defined ammonium carbonates—the normal carbonate, the hydrocarbonate, and the sesquicarbonate. On the other hand, in his paper Ueber die Verbindungen des Ammoniaks mit der Kohlensaure (1839), H. Rose claimed to have shown that an indefinitely large number of these compounds can be prepared, and he described twelve of them. He said ... 

In principle, each factor can be defined by one or several variables the factor catalyst might, for instance, be characterized by the three variables nature, concentration, and granulometry. However, in the defined case to be presented, each factor was characterized by one variable (Table 2), and both terms are used indistinctly. Five natural variables (denoted re-... 

Many studies have been carried out concerning the stability constants of humic and fulvic acid complexes.188 190,191 Stability constants vary considerably with pH and ionic strength213 and this, together with the variable nature of the ligands involved, accounts for the range of values reported for individual metal ions in the literature. However, the stabilities of divalent metal complexes generally follow the well-known Irving-Williams order Mg < Ca < Mn < Co < Zn = Ni < Cu < Hg. 

Confounding Factors in Clinical Trials The Variable Natural History of Most Diseases... 

Hulme M. Barrow E.M. Arnell N.W. Harrison P.A. Johns T.C. and Downing T.E. (1999). Relative impacts of human-induced climate change and climate variability. Nature, 397, 689-691. 

The variable nature of the X3 species in the isoelectronic series, form a general model for electronic delocalization, enabling one to classify the species either as distortive or as stable ones. Using the isoelectronic analogy, one might naturally ask about the isoelectronic Tr-species in allyl radical does it behave by itself like H3 or like Li3 Moreover, the same two extreme VBSCDs for X3 in Fig. 6.19 can be shown for X3 +, X3, X4 and X6 species (64). Likewise one might wonder about the status of the corresponding isoelectronic -n-components in allyl cation, anion, cyclobutadiene, or benzene. These questions were answered in detail elsewhere and the reader is advised to consult a recent review (64). Below we briefly discuss the problem of one of our molecular icons, benzene. 

I. S. Kulaev and L. A. Okorokov (1968). The variable nature of the uptake of phosphate from the medium by Penicillium chrysogenum (in Russian). Dokl. Akad. Nauk SSSR, 179, 982-984. 

Nature identical oils A combination of synthetically produced chemicals, or chemicals extracted from cheap oils, made to imitate a genuine essential oil. Owing to the complex and variable nature of natural essential oils, synthetics cannot hope to replicate their properties and are not suitable for aromatherapy. 

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