Average Growths Research Articles

Hybridization in Sunfishes (Lepomis, Centrarchidae) Based on Time-Growth and Static Allometry

A statistical method of analyzing for hybridization based on exponential growth curves is presented. It is pointed out that with "truly cross-sectional data" such as those on the sunfishes (genus Lepomis) reported here, it is possible to analyze for hybridization based on static variations separately from that based on the average growths of populations. The technique of statistical linear comparisons is extended to analyze for the degree of intermediacy of the hybrids as an alternative to the hybrid index approach. Applications of the statistical method of analyzing for hybridization based on the constants of exponential curves and of the method based on static allometry are shown on a real set of data for the first time.

ANALYSIS OF A FOREST MANAGEMENT SITUATION BY LINEAR PROGRAMMING

SUMMARY The forest was described as consisting of 26 classes of trees in which the total numbers of trees, the average sawlog volumes per tree, and the average growths of sawlog volume per annum were known. The annual cut was prescribed in advance, and limits were placed on the volume of 14-inch trees that were to be harvested and the average sawlog volume of all trees harvested. Analysis by linear programming to determine the optimal harvesting program for least reduction of current growth of sawlog volume produced a program which was suitable for use in the forest as a set of prescriptions for tree-marking. Supplementary analysis by parametric programming showed the effects of varying some of the factors of the situation.

A study of the fasting metabolism of various breeds of hog: III. Metabolism and surface area measurements.

From metabolism experiments carried out on the pigs enumerated in the first paper of this series the following conclusions are drawn:(a) The metabolism in a state of inanition appears to be more a function of a power of the weight than of the true surface area as determined by the photographic method.(b) Hogs born in the summer and autumn of one year appear to show two maxima of metabolism; one almost immediately, as has been observed previously, and another during the following summer, provisionally ascribed to the effect of light on thyroid activity, produced by the intermediary action of the anterior pituitary.(c) Actual, and theoretically computed average growths are shown to agree remarkably well in the case of eleven of the pigs which were treated in an exactly similar manner. Individual growth curves showed no such agreement. This is considered to strengthen the evidence for the writer's previously stated view that nett energy is a statistical rather than a physiological constant.