Strong Positive Correlation Coefficient Research Articles

Influence of phenobarbital on the hepatic handling of [3H]vitamin D3 in the dog.

The effect of phenobarbital (PB) on the hepatic handling of vitamin D3 (D3) and its metabolism to 25-hydroxyvitamin D3 [25(OH)D3] was studied in eight mongrel dogs. The hepatic uptake and clearance of [3H]D3 were evaluated by the multiple indicator-dilution curve technique, and the formation of [3H]25(OH)D3 was evaluated by sampling the hepatic effluent. The hepatic enzyme induction was assessed in six dogs by the 14CO2 breath excretion test. The results show that the hepatic uptake of [3H]D3 was not significantly affected but that its hepatic clearance was significantly increased during PB treatment. The [3H]25(OH)D3 production was increased during PB administration by a factor of 3-5 times over the pre- or post-PB period. Evaluation of the enzyme induction produced by PB revealed that two of the dogs studied had a blunted response to PB; furthermore, these dogs were the only animals that showed no increase in [3H]25(OH)D3 production during PB treatment and that in the presence of similar serum PB, endogenous 25(OH)D3 and 1,25-dihydroxyvitamin D3 pools, and hepatic uptake and clearance of [3H]D3. Strong positive correlation coefficients were observed between the breath excretion of 14CO2 and the [3H]25(OH)D3 production during PB treatment, whereas no correlation was present in the absence of PB. These observations show that, in most animals, PB is accompanied by an increased hepatic clearance of [3H]D3 and by an increased production of [3H]25(OH)D3. The data obtained during the present study also show that the response to PB is heterogeneous and that some animals escaped PB-mediated enzyme induction.(ABSTRACT TRUNCATED AT 250 WORDS)

Stability of individual loudness functions obtained by magnitude estimation and magnitude production

A correlational analysis of individual magnitude estimation and production exponents at the same frequency has been performed as well as an analysis of individual exponents produced across frequency (250, 1000, and 3000 Hz). Results show, in agreement with those of Wanschura and Dawson [J. Exp. Psychol. 102, 806-812 (1974)], that a moderately positive but not significant correlation coefficient is obtained between individual magnitude estimation and production data. However, strong positive correlation coefficients are found when individual magnitude estimation and production data are combined and then, compared across frequency. These results imply that individual differences in exponents not only persist over time but also remain stable across changes in stimulus frequency. Further results disclose that the slope (exponent) of the equal-sensation function between two different stimuli can be predicted from individual magnitude estimation and production data. Examples are given showing that the stability of individual exponents can be used to predict the slope of the loudness-recruitment function produced by ears with cochlear pathology, i.e., transitivity can be achieved for individuals.

Genotypic and Phenotypic Variances and Correlations in Peas1

AbstractEight lines of peas (Pisum sativum L.) and all possible Fl's among them were grown in five environments to study the genotypic and phenotypic variances and correlations among eight traits. Genotypes and environments had highly significant effects on all traits. Parents exhibited highly significant genotype × environment interactions but Fl's were remarkably stable.Plant height was often positively correlated with pods/plant, seeds/plant, and yield/plant, indicating superior yielding ability of taller plants. However, indeterminate growth is unacceptable in peas for canning because of the range in maturity of peas borne at the different nodes and the excessive vine growth which interferes with harvesting. Correlations of percentage seed protein with the different traits were variable, but generally positively correlated with increased yield. There was some indication of lower protein with heavier seeds. Strong positive genotypic and phenotypic correlation coefficients obtained between pods/plant and seeds/plant, seeds/pod and seeds/ plant, and between those two traits and yield/plant, indicate that selection for either or both of these traits would result in superior yield. The genotypic correlation between weight/seed and yield was high, but the phenotypic association was low.

Phosphorus, iron, and manganese distribution in sediment cores of six Wisconsin lakes1

Depositional patterns of iron, manganese, and phosphorus in one central and five northern Wisconsin lakes ranging from oligotrophic to eutrophic, primarily from natural causes, have been investigated. One‐meter cores from one or more locations within each lake were analyzed. The historical pattern of iron and manganese deposition is closely related to the pattern of phosphorus deposition in most of the cores. Four of the nine cores show a strong positive correlation coefficient between P and Fe and seven between P and Mn. Manganese has more predictive value than iron for determining the concentration of phosphorus in a given core; however, the iron content appears to be the dominant factor in the phosphorus sorptive and retentive capacity of sediments.