The interaction of aging and 10 years of racing on ultraendurance running performance

The aim of this study was to examine the interaction between aging and 10 years of racing in endurance runners. Race-time data from 194 runners who had completed 10 consecutive 56-km ultramarathons were obtained. The runners were either 20.5 +/- 0.7, 30.0 +/- 1.0, 39.9 +/- 0.9, or 49.4 +/- 1.0 years old at their first race. Each runner's race speed was determined for each race over the 10 years. Data were analyzed using repeated-measures ANOVA, one-way ANOVA, and independent t tests and showed that performance improved and declined at greater rates for younger runners; younger runners had a greater capacity for improvement than older runners; approximately 4 years were required to reach peak racing speed, regardless of age; it was not possible to compete at peak speed for more than a few years; and the combined effects of 10 years of aging and racing neither improve nor worsen net performance. In conclusion, these data suggest that although these runners showed similar patterns of change in race speed over a 10-year period, the extent of change in performance was greater in younger than in older runners.     

A GALTON-WATSON BRANCHING PROCESS IN VARYING ENVIRONMENTS WITH ESSENTIALLY CONSTANT OFFSPRING MEANS AND TWO RATES OF GROWTH1

A Galton-Watson process in varying environments (Z_n), with essentially constant offspring means, i.e. E(Z_n)/mⁿ→α∈(0, ∞), and exactly two rates of growth is constructed. The underlying sample space Ω can be decomposed into parts A and B such that (Z_n)_n grows like 2ⁿon A and like mⁿon B (m > 4).     

Projection and Misperception in Couples Treatment

Projective identification is discussed as an interpersonal mechanism involved in distortions of perceptions and communications. Several case illustrations are presented to show how this mechanism manifests itself in relatively healthy, though neurotic, couples. A treatment approach based on correction of the perceptual distortions is suggested as a model for short-term counseling with such couples.     

ESTIMATING SUPPLY DESPITE A QUOTA: BRAZIL'S SUPPLY OF SUGAR

In this paper a model is developed from which the supply curve, of a stochastically produced good, can be estimated when the observations are constrained by a quota. It is shown that, for any (price, quantity) combination observed in the presence of a quota, we can simulate a corresponding (price, quantity) combination which could have been observed in the absence of a quota. This procedure is then employed to construct "free-market" observations on Brazil's supply of sugar, with which the supply curve is then estimated, and production in the absence of sugar quotas inferred.     

Distribution of power and agrarian reform: An explanatory model applied to India and Chile

This article appraises within an interdisciplinary framework key social, political, and economic aspects of the distribution of power in agrarian societies, and their interaction with various agrarian reform measures. Reform measures investigated include land reform proper, tenancy and wage regulations, land taxes, institutional credit, and productivity promotion measures.Use is made of alternate models that simulate economic development and agrarian reform under alternative sociopolitical regimes. The models distinguish four actor-groups: landlords, peasants, nonagriculturalists, and the state. Regimes differ, on the one hand, according to which actor-group is in power, and, on the other hand, according to which instruments of economic policy the state employs. The models are empirically applied and used to analyze the impact of agrarian reform measures in the 1960s and 1970s in two different regimes, India and Chile (under Allende).     

AN APPROXIMATE MAXIMUM LIKELIHOOD ESTIMATOR FOR CHAIN BINOMIAL MODELS

Using the Poisson approximation to the Binomial distribution, we construct an approximate maximum likelihood estimator (MLE) for a class of chain binomial models. Our estimator proves to have properties which may make it preferable to the exact WLE.     

SOME ECONOMIC CONSEQUENCES OF ANTICIPATING TECHNICAL ADVANCE

Using a simple model of a long run profit maximizing firm, we investigated the consequences of foreseeing future technical advance upon the adoption of new technology, scrapping of old, and for price and output of the firm's product. To simplify the analysis and highlight the conclusions, we assumed all technologies embodied in equipment and all equipment infinitely durable. It was shown that the often-used formulas for the unit cost of using capital over a finite (rkj/(l — a^T)) or infinite (rkj) life are appropriate only if the equipment does not become outmoded during its economic life and if there are no demand shifts in that time interval. Otherwise, the current cost of using capital (ex ante) must reflect future lesser or greater earning power of that capital due to outmodedness or demand shifts. Anticipation of technical advance tends to delay scrapping of old equipment and retard installation of new, with current output smaller and price higher than if technology is stagnant. Selection among currently competing technologies is also affected by the course future technical advance is expected to follow. The economic lifetime of capital equipment is independent of the elasticity of demand for the firm's output. On the other hand anticipation of demand expansion tends to partially or wholly offset the effect of anticipating future technical advance, while expected demand decline tends to reinforce it. Uncertainty about when improved technology will appear tends to retard adoption of current best practice technology, to retard scrapping of outmoded technology, restrict output and elevate price, in comparison with pptimal policy when the time of availability is believed known. The optimal policy is unaffected when it is the magnitude of the improvement rather than its timing which is unknown.     

Changes in Americans' Policy Preferences, 1935-1979

Using responses to 3,315 survey questions asked of nationalsamples, we examine how policy preferences of Americans havechanged over the last 45 years. The data indicate that therehas been considerable stability in public opinion: responsesto half the 613 repeated policy items show no significant changeat all; approximately half the detectable changes were lessthan 10 percentage points; and rarely did preferences fluctuatesignificantly back and forth within a short time period. Foreignpolicy changes were no larger or more frequent than domestic,but they did tend to occur more abruptly. When opinion shiftsoccurred, they were not random or capricious; they were usuallyrelated to important changes in citizens' social and economicenvironments. Rapid shifts generally coincided with major eventsin international affairs or the economy.     

The negotiating style of Saudi industrial buyers: An empirical investigation

This study investigates the negotiating styles of Saudi industrial buyers. Thomas’s Topology as measured by Rahim’s instrument is used in this study. The results suggest that three are two dominant styles of negotiation in the Saudi context, namely: the competitive and collaborative styles.