Population growth,farmland, and the long-run standard of living

This paper studies the natural-resources element in the theory of population growth over the very long run. In the context of the stock of land and Malthusian crises in earlier times, the model shows how resources have become more available rather than more scarce, even as population and income have increased.The paper sketches a mechanism which, added to the Malthusian system, leads to entirely different conclusions than does the Malthusian system. Using the illustration of food and land, change in knowledge and hence in the stock of resources is made a function of the stock of knowledge and the price of resources. The speed of adjustment depends on the economic and social climate for the development of new knowledge. Population growth first raises food and land prices, which then stimulate the creation of new resources, eventually leading to less scarcity of resources and lower prices than originally prevailed.That is, population growth creates new problems which in the short run constitute additional burdens which, in the longer run, lead to new developments that leave people better off than if the problems had never arisen.This paper benefitted from being presented in earlier draft at a Population Association of America meeting, to the Economic History workshop at the University of Illinois, and to a seminar of the International Union for the Scientific Study of Population in New Delhi. We appreciate valuable comments on earlier drafts from Stanley Engerman, E. L. Jones, William McNeill, and two anonymous referees. Gunter Steinmann acknowledges financial support from the Volkswagen Foundation and a travel grant from Fulbright Commission.     

Implementation and process evaluation of a student "school-as-community" group. A component of a school-based drug abuse prevention program

Little documentation exists regarding the functioning of formalized adolescent groups as drug abuse prevention agents. Two studies are described that were conducted at high schools whose students are at high risk for drug abuse. Twenty-one schools were randomly assigned to one of three conditions: (a) standard care, (b) classroom drug abuse education only, or (c) classroom plus school-as-community. Results of the first study indicated that the school-as-community component--which involved weekly meetings and periodic events at seven schools--was implemented as planned, drug abused focused, and perceived as productive in discouraging drug abuse. In the second study, staff in the classroom plus school-as-community condition self-reported involvement in the greatest number of community activities across the school year, compared with staff from the other two conditions. These two studies support the feasibility of formalized groups of high-risk youth to promote drug-free events.     

There is no low-level fertility and development trap

Summary The theory of the low-level equilibrium trap asserts that an increase in income stimulates population growth sufficiently so that the additional people 'eat up' the 'surplus' over subsistence, and hence drive the level of income back to subsistence. Originally the theory referred primarily to mortality, but nowadays its application is to fertility. In the long-run equilibrium context in which the theory is ordinarily presented, the fact that the long-run elasticity of fertility with respect to income is negative in less developed countries fatally contradicts the accepted version of the trap. But to give every chance for trap theory to be meaningful, the paper presents a period-by-period analysis, embodying larger-than-observed positive elasticities during the early years and the logically necessary counterbalancing negative elasticities during the later years. These elasticities are combined with consumption and production figures for various age groups to estimate the effect in each year after the windfall, and altogether. The results show that even under assumptions not charitable to the conclusion of this paper, additional children do not even come close to 'eating up' the increase in income which induced their births, so that the trap theory is falsified.     

Child custody issues and co‐occurrence of intimate partner violence and child maltreatment: controversies and points of agreement amongst practitioners

The situation of families undergoing separation in a context of co‐occurrence of intimate partner violence (IPV) and child maltreatment raises certain issues related to child custody. The results presented in this paper were collected and analysed within the framework of a qualitative study aiming to identify the principal points of agreement and the main controversies amongst practitioners in several different types of organizations. Focus groups were held with a total of 43 practitioners from six different settings concerned with child custody in cases of co‐occurrence of IPV and child maltreatment. Although they agreed on the importance of ensuring the safety of victims of violence, their views diverged on three points: (1) the importance of preserving the father–child relationship; (2) collaboration between voluntary organizations and semi‐voluntary or legal agencies; and (3) consideration of cultural differences.     

Distance sampling methodology

We consider the method of distance sampling described by Buckland, Anderson, Burnham and Laake in 1993. We explore the properties of the methodology in simple cases chosen to allow direct and accessible comparisons of distance sampling in the design- and model-based frameworks. In particular, we obtain expressions for the bias and variance of the distance sampling estimator of object density and for the expected value of the recommended analytic variance estimator within each framework. These results enable us to clarify aspects of the performance of the methodology which may be of interest to users and potential users of distance sampling.     

A New Model of Trend Inflation

This article introduces a new model of trend inflation. In contrast to many earlier approaches, which allow for trend inflation to evolve according to a random walk, ours is a bounded model which ensures that trend inflation is constrained to lie in an interval. The bounds of this interval can either be fixed or estimated from the data. Our model also allows for a time-varying degree of persistence in the transitory component of inflation. In an empirical exercise with CPI inflation, we find the model to work well, yielding more sensible measures of trend inflation and forecasting better than popular alternatives such as the unobserved components stochastic volatility model. This article has supplementary materials online.     

Advances in the surgical management of prolapse

Prolapse is an extremely common condition, for which 11% of women will have a surgical procedure at some point in their lives. The recurrence rate after most of the traditional surgical procedures is high and upto 29% of women who have had surgery for prolapse will require a further operation. In order to improve the surgical outcome, there is currently much interest in the use of grafts to augment traditional repairs and new procedures have been developed using specifically developed grafts. These have been combined with minimally invasive surgical techniques in an attempt to reduce surgical morbidity. These procedures may improve the outcome of surgery for prolapse. However, there is currently a lack of long-term data from randomized trials to demonstrate their effectiveness and safety.