THE APPLICATION OF AN INDEX TO DETERMINE GENETIC AND ENVIRONHENTAL CONTRIBUTIONS TO DENTOFACIAL GROWTH IN TWINS AND SIBLINGS

The method of principal components may be used to reduce a large quantity of data for an individual into a single statistic, a growth index, indicative of overall facial growth, and to make a determination of the relative contribution of each variable, as well as the genotype and the environment, to the variation between individuals, When this method is applied to four consecutive years of cephalometric and anthropometric data from each of 95 children, consisting of Caucasian and Negro monozygotic twins, like-sexed dizygotic twins, and their siblings of both sexes, it discloses that: 1. The relative contributions of the variables studied to the variation among individuals are as follows: facial depth variables \u3e facial height variables \u3e facial width variables. 2. No differences in growth rates, as represented by the growth index, are apparent between males and females entering the study during the same age interval, between members of the same sex entering the study during two age intervals, between sexes including all age intervals, and between races. Failure of the investigation to disclose any such differences may result from the design of the experiments. 3. A very highly significant environmental component of variability for the growth index is found in the population studied, which suggests the need for further studies of specific environmental agents affecting the growth rates of the variables involved. 4. A very highly significant genetic component of variability for the growth index also is found, however, the complicated polygenic nature of facial inheritance renders analysis of the specific genetic factors involved quite difficult, because of the present limited knowledge of the inheritance of quantitative traits. 5. A very highly significant extrafamilial (genetic and environmental) component of variability for the growth index also is found. 6. The sources of variability for the growth index for twins, have the following relative magnitudes: extra-familial \u3e genetic \u3e environmental \u3e error. For siblings the relative magnitudes of the sources of variability are: extrafamilial \u3e environmental\u3e genetic \u3e error. Thus, as expected, environmental factors are relatively more important between siblings than between twins

Industrial production and capacity utilization: 1998 annual revision

In late 1998, the Federal Reserve published the results of an annual revision of its measures of industrial production, capacity, and capacity utilization, which cover the nation's manufacturing, mining, and electric and gas utilities industries. The revision involved both the incorporation of newly available and more comprehensive source data and, for some series, the introduction of modified methods for compiling the series. The revised figures show stronger growth of both production and capacity since 1996; however, the overall capacity utilization rate was little changed from the previous data.Industrial production index ; Industrial capacity

The Zero-Information-Limit Condition and Spurious Inference in Weakly Identified Models

The fact that weak instruments lead to spurious inference is now widely recognized. In this paper we ask whether spurious inference occurs more generally in weakly identified models. To distinguish between models where spurious inference will occur from those where it does not, we introduce the Zero-Information-Limit-Condition (ZILC). When ZILC holds, the information or precision of parameter estimates is overestimated. We discuss how ZILC applies to models encountered in practice and show that spurious inference does occur when ZILC holds.

A nation of spendthrifts? An analysis of trends in personal and gross saving

The steep drop in the U.S. personal saving rate over the last decade has fueled speculation that Americans are spending recklessly. But alternative measures of personal saving show that households are actually setting aside a larger share of their resources than the official figures suggest. In addition, government saving has risen markedly, leading to an increase in overall domestic saving that has helped finance a surge in U.S. investment.Saving and investment ; Finance, Personal

Fiscal policy in an era of surpluses: economic and financial implications - summary of observations and recommendations

Fiscal policy ; Budget

Uncertainty in Fisheries Economics: The Role of the Discount Rate

Standard models of management of a single-species fishery generally assume that the biomass is of known size and that it is generated by a well-specified deterministic growth law. In reality the biomass is of uncertain size and usually subject to random growth. Several authors have addressed the problem of random growth assuming a known initial biomass and have shown that lowering the planning discount rate proportional to the variance is an optimal planning procedure assuming small perturbations. In this paper we assume that the growth function is nonrandom but dependent upon a biomass stock of unknown size. We shall show that a planner should raise the discount rate relative to the certainty equivalent case by an amount related to society's distaste for risk in order to manage the biomass optimally over time. As is to be expected, the optimal steady-state biomass will be less than would occur in a situation of certainty.Environmental Economics and Policy, International Development, Resource /Energy Economics and Policy, Risk and Uncertainty,

The predictive abilities of the New York Fed's Empire State Manufacturing Survey

Business surveys often give early signals of the direction and magnitude of economic activity. One release, the relatively new Empire State Manufacturing Survey, is demonstrating an ability to provide information ahead of U.S. production and employment trends. In fact, the predictive power of this survey appears to be at least equal to that of two established manufacturing surveys. This issue is part of the Second District Highlights series.Manufactures - New York (State) ; Economic indicators ; Forecasting