John Gibson

Migration and mental health : evidence from a natural experiment

People migrate to improve their well-being. Yet a large literature suggests that migration can be a stressful process, with potentially negative impacts on mental health. However, to truly understand the effect of migration one must compare the mental health of migrants to what their mental health would be had they stayed in their home country. The existing literature is not able to do this. New Zealand allows a quota of Tongans to immigrate each year with a random ballot used to choose amongst the excess number of applicants. Experimental estimates of the mental health effects of migration are obtained by comparing the mental health of migrants who were successful applicants in the random ballot to the mental health of those who applied to migrate under the quota, but whose names were not drawn. Migration is found to lead to improvements in mental health, particularly for women and those with poor mental health.

A Forward-Looking Measure of the Stock of Human Capital in New Zealand

Human capital is increasingly believed to play an important role in the growth process; however, adequately measuring its stock remains controversial. Because the estimated impact that human capital has on economic growth is sensitive to the measures or proxies of human capital, accurate and consistent measures are needed. While many measures of human capital have been developed, most rely on some proxy of educational experience and are thus plagued with limitations. In this study, we modify the lifetime labour income approach outlined by Jorgenson and Fraumeni (The Measurement of Savings, Investment and Wealth, Chicago, IL, University of Chicago Press, 1989, pp. 227–282; Output Measurement in the Services Sector, Chicago, IL, University of Chicago Press, 1992, pp. 303–338) to estimate the monetary value of the human capital stock for New Zealand. Based on data from the New Zealand Census of Population, we find that the countrys working human capital grew by half between 1981 and 2001, mostly due to the rise in employment level. This stock of human capital was also well over double that of physical capital in all the census years studied.

Synthesis and Comparison of Two's Complement Parallel Multipliers

A machine word mathematical formulation is applied to analysis and synthesis of circuits for signed binary number multiplication. The circuits are related to each other and to contemporary circuit algorithms in the course of the syntheses and in a comparative discussion. Circuits with complemented multiplier/multiplicand (M̄) or complemented partial product word (P̄) corrections offer advantages in circuit symmetry and algorithmic structure.

Household Bargaining Over Wealth And The Adequacy Of Women'S Retirement Incomes In New Zealand

Abstract Bargaining models of household wealth accumulation point to a potential conflict of interest between husbands and wives. Wives are typically younger than their husbands and have longer life expectancy, so they must expect to finance a longer retirement period. Therefore, when they have greater relative bargaining power, households will accumulate more wealth. There is some weak evidence for this in the United States, but this article finds the opposite pattern in New Zealand, where womens greater bargaining power results in a lower net worth in the pre-retirement cohort of couples. In New Zealand, where public pensions are more generous than in the US and are not affected by holdings of private wealth or income, it may not be rational for women with greater relative bargaining power than their spouses to favor wealth accumulation. These results indicate the importance of the policy context when considering household bargaining models.

Fast Hybrid Computer Implementation of the Dynostat Algorithm

In optimal resource allocation problems the Dynostat algorithm separates the overall optimization task into less complicated optimum seeking techniques working in parallel. A hybrid computer implementation is shown to provide a much faster optimizer than was previously the case using a digital computer. Solution accuracies are considered adequate for many practical applications. The improved formulation presented of gradient search is advantageous for high-speed optimization. Confidence is increased in analog computer solutions by introducing auxiliary algorithms that check on solution feasibility and also improve accuracy.

A Unifying Zero-Zone Function Approach to Restrained System Optimization

A restraint-pair formulation for system equality and inequality restraints in both state and control variables is synthesised using ``zero-zone function forms. The resulting unification of different categories of algebraic restraints leads to simplified problem representations and to systematic programming routines for problems in restrained optimization.

A Parallel Optimum Seeking Technique-Dynostat

Dynostat is the name given to a system optimization technique employing both instantaneous and predictive optimum seeking strategies in parallel. Although it has both off-line and on-line capabilities of application this account is concerned mainly with an explanation of the essentials of the technique in the context of off-line optimization studies. A brief description of a successful application study of a practical problem in industry is also included. The technique is explained in a progressive manner by considering an example for which there is a requirement for an optimum schedule of alternative energy sources. As is well known, optimum scheduling using the dynamic programming technique is restricted in practice by limitations in computer storage and computing time to systems with few independent variables. However, in certain classes of multichannel systems some of these variables appear naturally, or by reasonable approximation can be made to appear, in a static section of the system, and it is shown that optimizing their values need consume only little computer time and storage. The remainder of the variables are in the dynamic section and their optimization makes a heavy demand on computational facilities. The Dynostat technique handles both types of variables in a single computer algorithm. An indication of a projected on-line configuration of Dynostat is presented in a statement of developments of the technique currently under study.

Policy reform and labour demand in branches of Sri Lankan manufacturing industry

Many policy reforms in developing countries aim to remove factor market distortions. Whether such reforms reduce unemployment depends partly on the substitution possibilities between labour and other factors of production. This paper examines labour demand in seven branches of Sri Lankan manufacturing industry, using data on 4-digit industrial categories over the 1990 to 1997 period. The Box–Cox transformation is used to allow for flexible, and data-dependent, elasticities. The elasticity of capital–labour substitution varies widely across the branches of industry and is usually variable rather than constant. The average, long-run own-wage elasticity of labour demand for the manufacturing sector is estimated as −0.80, so factor price policy should have an important effect on labour demand in this setting.