Correlation studies

Biomarkers form a small percentage of bitumen and cmde oils, but relative distributions and complex stmctures are modified by the various processes involved during petroleum generation and accumulation. These biomarkers are widely used for correlation studies, and for recognition and documentation of the progress of generation and maturation (52,53). 

Electron correlation studies demand basis sets that are capable of very high accuracy, and the 6-31IG set I used for the examples above is not truly adequate. A number of basis sets have been carefully designed for correlation studies, for example the correlation consistent basis sets of Dunning. These go by the acronyms cc-pVDZ, cc-pVTZ, cc-pVQZ, cc-pV5Z and cc-pV6Z (double, triple, quadruple, quintuple and sextuple-zeta respectively). They include polarization functions by definition, and (for example) the cc-pV6Z set consists of 8. 6p, 4d, 3f, 2g and Ih basis functions. 

Objective Evaluation of Color. In recent years a method has been devised and internationally adopted (International Commission on Illumination, I.C.I.) that makes possible objective specification of color in terms of equivalent stimuli. It provides a common language for description of the color of an object illuminated by a standard illuminant and viewed by a standard observer (H). Reflectance spectro-photometric curves, such as those described above, provide the necessary data. The results are expressed in one of two systems the tristimulus system in which the equivalent stimulus is a mixture of three standard primaries, or the heterogeneous-homogeneous system in which the equivalent stimulus is a mixture of light from a standard heterogeneous illuminant and a pure spectrum color (dominant wave-length-purity system). These systems provide a means of expressing the objective time-constant spectrophotometric results in numerical form, more suitable for tabulation and correlation studies. In the application to food work, the necessary experimental data have been obtained with spectrophotometers or certain photoelectric colorimeters. 

The correlation studies of heat and mass transfer in pellet beds have been investigated by many, usually in terms of the. /-factors (113-115). According to Chilton and Colburn the two. /-factors are equal in value to one half of the Fannings friction factor / used in the calculation of pressure drop. The. /-factors depend on the Reynolds number raised to a factor varying from —0.36 to —0.68, so that the Nusselt number depends on the Reynolds number raised to a factor varying from 0.64 to 0.32. In the range of the Reynolds number from 10 to 170 in the pellet bed, jd should vary from 0.5 to 0.1, which yields a Nusselt number from 4.4 to 16.1. The heat and mass transfer to wire meshes has received much less attention (110,116). The correlation available shows that the /-factor varies as (Re)-0-41, so that the Nusselt number varies as (Re)0-69. In the range of the Reynolds number from 20 to 420, the j-factor varies from 0.2 to 0.05, so that the Nusselt number varies from 3.6 to 18.6. The Sherwood number for CO is equal to 1.05 Nu, but the Sherwood number for benzene is 1.31 Nu. 

In Table 3 we have listed the results of a basis set and correlation study for the hyperpolarizability dispersion coefficients. In a previous investigation of the basis set effects on the dispersion coefficients for the first hyperpolarizability (3 of ammonia [22] we found quite different trends for the static hyperpolarizability and for the dispersion coefficients. While the static hyperpolarizability was very sensitive to the inclusion of diffuse functions, the dispersion coefficients remained almost unchanged on augmentation of the basis set with additional diffuse functions, but the results obtained with the CC2 and CCSD models, which include dynamic electron correlation, showed large changes with an increase of the... 

Gerike P, WK Fischer (1981) A correlation study of biodegradability determinations with various chemicals in various tests. 11. Additional results and conclusions. Ecotoxicol Environ SafS 45-55. 

The study is based on four iinear hydrocarbons (in Ci, Ce to Ca) and the model uses Antoine and Clapeyron s equations. The flashpoints used by the author do not take into account all experimental values that are currently available the correlation coefficients obtained during multiple linear regression adjustments between experimental and estimated values are very bad (0.90 to 0.98 see the huge errors obtained from a correlation study concerning flashpoints for which the present writer still has a coefficient of 0.9966). The modei can be used if differences between pure cmpounds are still low regarding boiling and flashpoints. 

P.N. Craig, Comparison of the Hansch and Free-Wilson approaches to structure-activity correlation, In Biological Correlations — The Hansch Approach (R.F. Gould, Ed.). Advances in Chemistry Series, No. 114. American Chemical Society, Washington DC, 1972, pp. 115-129. P.N. Craig, Interdependence between physical parameters and selection of substituent groups for correlation studies. J. Med. Chem., 14 (1971) 680-684. 

Clinical correlation studies between CA 27.29 levels and CA 15-3 levels typically yield correlation coefficients of >0.95. It has been suggested that the epitope mapping studies reflect that the CA 27.29 antigen is essentially the same breast cancer-associated mucinous antigen detected by the two methods. 

At least two correlation studies on the aqueous solubilities of liquid organic compounds have been published [18, 19], and in each case an excellent correlation (r > 0.9) was obtained. For both liquid and solid compounds, log P or CLOGP accounts for a major portion of variance in water solubility [3, 4, 20]. However, the... 

Hirono, S., Nakagome, I., Hirano, H. Matsuhita, Y., Yoshi, F., Moriguchi, I., Non-congeneric structure-pharmacokinetic property correlation studies using fuzzy adaptive least squared oral bioavailability, Biol. Pharm. Bull. 1994, 37, 306—309. 

IR studies into new prominence is very promising correlated studies with these techniques and with electrical studies should lead to great progress if we have the required funding, persistence and patience. 

Rodriguez, G., Cogorno, P., Gris, A. et al. Regional cerebral blood flow and anxiety a correlation study in neuro-logically normal patients. /. Cereb. Blood Flow Metab, 9 410-416,1989. 

In many studies it is desirable to gain information from both LM and EM. Methods have been devised for such correlative studies (30-32). Sawada and Esaki s method (33) was designed to address factors that they believed to be important for accurate comparison. These factors are the transparency and thinness of embedded blocks, the flatness of tissue sections, and ease of removal of embedding molds from polymerized Epon blocks. Sawada and Esaki s method is summarized below. 

In nucleic acids, the cross-correlation studies were applied to investigation of the sugar conformation [101-103] of the phosphodiester backbone [65] as well as to some more spe-... 

Two activity coefficient models have been developed for vapor-liquid equilibrium of electrolyte systems. The first model is an extension of the Pitzer equation and is applicable to aqueous electrolyte systems containing any number of molecular and ionic solutes. The validity of the model has been shown by data correlation studies on three aqueous electrolyte systems of industrial interest. The second model is based on the local composition concept and is designed to be applicable to all kinds of electrolyte systems. Preliminary data correlation results on many binary and ternary electrolyte systems suggest the validity of the local composition model. 

Correlative studies revealed that the faster the rate of nitronate formation, the higher the yields of the hydroxamic acids130 (equations 103 and 104). 

Kvenvolden KA, Rapp JB, Bourell JH (1985) In Magoon LB, Claypool GE (eds) Alaska North Slope oil/rock correlation study. American Association of Petroleum Geologists, Tulsa, OK, Study in Geology, No 20, p 593... 

The chromatographic retention parameters used in correlation studies are normally assumed to be proportional to the free energy change. 

J. L. Fauchere, M. Charton, L. B. Kier, A. Verloop, V. Pliska, Amino Acid Side Chain Parameters for Correlation Studies in Biology and Pharmacology , hit. J. Pept. Protein Res. 1988, 32, 269 - 278. 

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