# SEARCH

** Correlation of weak and strong field approximations **

Consideration of Weak Correlation. If an inter-needle correlation can no longer be disregarded, two published methods for the analysis of weakly correlated particles may be considered (Cohen and Thomas [201] Porod [206]). [Pg.184]

In the present work, we will use a relatively low level of theory to derive 32 weakly correlated molecular descriptors, each based on the subdivision and classification of the molecular surface area according to three fundamental properties contribution to ClogP, molar refractivity, and atomic partial charge. The resulting collection will be shown to have applicability in QSAR, QSPR, and compound classification. Moreover, the derived 32 descriptors linearly encode most of the information of a collection of traditional mathematical descriptors used in QSAR and QSPR. [Pg.262]

Studies to date have demonstrated an extremely weak correlation (if any) between photochemical-oxidant pollution and hospital admissions. If such correlations do exist, observations must be carried out over considerably longer periods with adequate provisions for controlling confounding variables, such as meteorologic factors. [Pg.421]

If the inputs are correlated, then the inverse of the covariance matrix does not exist and the OLS coefficients cannot be computed. Even with weakly correlated inputs and a low observations-to-inputs ratio, the covariance matrix can be nearly singular, making the OLS solution extremely sensitive to small changes in the measured data. In such cases, OLS is not appropriate for empirical modeling. [Pg.35]

NOE theory provides an exact energy functional for two-electron systems [76, 77]. In the weak correlation limit, the total energy is given by [Pg.410]

We have derived three sets of (easily calculated) molecular descriptors based on atomic contributions to logP, molar refractivity, and atomic partial charge. The individual descriptors were found to be weakly correlated with each other [Pg.276]

In a screening study with 78 subjects, the lag phase varied from 34 to 114 min. Interestingly, only a weak correlation was found between the a-tocopherol content and the lag phase (r=0.2, P < 0.01, n = 78). Increasing the a-tocopherol content of individual LDL samples in vitro or by oral supplementation led always to a proportional increase of oxidation resistance, according to the equation y=kx+a. The slope k is the eflScacy of [Pg.47]

Three sets of molecular descriptors that can be computed from a molecular connection table are defined. The descriptors are based on the subdivision and classification of the molecular surface area according to atomic properties (such as contribution to logP, molar refractivity, and partial charge). The resulting 32 descriptors are shown (a) to be weakly correlated with each other (b) to encode many traditional molecular descriptors and (c) to be useful for QSAR, QSPAR, and compound classification. [Pg.261]

In summary, it is more common to examine pairs of variables from a profit chain-of-effects model rather than the profit chain in its entirety. A scatter plot or correlation analysis of a pair of profit-chain variables (e.g. satisfaction and loyalty) almost always indicates a weak correlation. The weak correlation is typically interpreted as suggesting a crisis whereby the implied profit chain-of-effects or cascading model is not supported. [Pg.195]

The effect of water temperature variation is logarithmically correlated with dispersant effectiveness [585]. Dispersant/oil ratios greater than approximately 1 40 or 1 60 result in a low dispersant effectiveness. Dispersion experiments were conducted to investigate the effects of oil composition. The effectiveness is positively and strongly correlated with the saturate concentration in the oil and is negatively correlated with the contents of aromatic, asphaltene, and polar compounds in the oil. The effectiveness is weakly correlated with the viscosity of the oil. The dispersant effectiveness is limited primarily by the oil composition. [Pg.305]

** Correlation of weak and strong field approximations **

© 2019 chempedia.info