Children's time in structured and unstructured leisure activities

Using the 1981 Time Use Longitudinal Panel Study data, this study examines factors which influence children's time use in leisure activities. More time is spent in unstructured than structured leisure activities. Analysis of variance is performed on 32 categories of leisure time, including total leisure, to determine the influence of characteristics of the child and the mother and other socioeconomic characteristics. Males spend significantly more time than females in active sports, playing games, and passive leisure especially watching television on weekends. Females spend significantly more time than males socializing on weekends. The amount of time spent socializing increases with age but decreases with employment. Time spent playing games decreases with age, increases with number of children, and decreases as family income increases. Given the large number of children who do not participate in a given set of leisure activities, future research should examine the probability of participation.The data used in this article were made available by the Inter-university Consortium for Political and Social Research. The data for Time Use Longitudinal Panel Study, 1975–1981 were originally collected by F. Thomas Juster, Martha S. Hill, Frank P. Stafford, and Jacquelynne Eccles Parsons of the Survey Research Center, Institute for Social Research, The University of Michigan. Neither the collector of the original data nor the Consortium bear any responsibility for the analysis or interpretation presented here.Carol B. Meeks is a Professor and Teresa Mauldin is an Assistant Professor in the Department of Housing and Consumer Economics, The University of Georgia, Athens, GA 30602. Dr. Meeks' research interests include time use, family structure, and economic aspects of housing. She received her Ph.D. from Ohio State University. Dr. Mauldin, who also received her Ph.D. from Ohio State University, is interested in time use, economic well being of individuals and families, and family structure.     

Simulation model of a predator-prey system comprised ofPhytoseiulus persimilis andTetranychus urticae. II. Model sensitivity to variations in the life history parameters of both species and to variations in the functional response and components of the numerical response

Summary A detailed sensitivity analysis of a model of a predator-prey system comprised ofTetranychus urticae andPhytoseiulus persimilis was performed. The aim was to assess the relative importance of the life history parameters of both species, the functional response, and the components of the numerical response. In addition, the impact of the initial predator-prey ratio and the timing of predator introduction were tested. Results indicated that the most important factors in the system were relative rates of predator and prey development, the time of onset of predator oviposition, and the mode of the predator's oviposition curve. The total oviposition of the predator, the effect of prey consumption on predator oviposition, and predator searching were important under some conditions. Factors of moderate importance were the adult female predator's functional response, total prey oviposition, the mode of the prey's oviposition curve, abiotic mortality of the pre-adult predator, and the effect of prey consumption on predator development and on the immature predator's mortality. Factors of least importance were the variances of the predator's and prey's oviposition curves, the abiotic mortality of the adult predator, the abiotic mortality of the pre-adult and adult prey, the functional response of the nymphal and adult male predators, and the effect of prey consumption on adult predator mortality. The sex ratios had little effect, except when the proportion of female predators was very low. The initial predator-prey ratio and time of predator introduction had significant impacts on system behavior, though the patterns of impact were different.     

Vacation farms and ecotourism in Saskatchewan, Canada

Vacation farms represent an increasingly significant rural diversification option for chronically unstable agriculture-based economies such as Saskatchewan. Concurrently, ecotourism is a rapidly expanding form of tourism which could serve to enhance the recreation product of such rural enterprises. Accordingly, a self-administered questionnaire was sent to all listed vacation farm operators in the province to obtain information on the provision of ecotourism opportunities. Just over one-half (n = 40) of all operations returned a completed questionnaire. Of 23 listed recreation options, wildlife viewing was cited as the activity most frequently undertaken by vacation farm visitors, followed by hunting, casual photography and touring. Wildlife viewing occurred most commonly during the spring and summer, with access to the resource occurring mainly on foot, and less so by horse and vehicle. Birds were the most important category of wildlife viewed, followed by mammals and plants; reptiles/amphibians, insects and fish were of only minor significance. It was evident that the sampled vacation farm operators possessed very little training in the area of ecotourism; few barriers or opportunities related to the latter were indicated. Appropriate recommendations include the provision of ecotourism training opportunities, stronger linkages between vacation farms and public spaces, and further investigation into the relationship between wildlife viewing and hunting activities.     

The Evolution of Organizations: Suggestions from Complexity Theory About the Interplay Between Natural Selection and Adaptation

There has been much debate in the managementliterature between neo-Darwinists (who believe in thenatural selection of populations of organizations) andadaptationists (who contend that changes in organization structure and behavior occur in response to theenvironment). The general thesis of neo-Darwinism isthat species are blindly selected for survival by theenvironment. The latest empirical support for the dominant neo-Darwinism perspective adopted bymost biologists is based primarily on the experimentsconducted by Salvador Luria who claims to haveconclusively demonstrated that genes mutate randomly.Recently, however, biologists have re-examined Luria sresearch methods and, after replications of hisexperiments, now question some aspects of the validityof his results. Moreover, there is now new researchwhich provides support for the earlier adaptationistposition, namely, the existence of evolutionary driversand directors existing within self-organizing systems.Of particular importance to the present study is the experimental indication thatself-organizing systems play a conscious role in theirown evolution. We propose that similar mechanisms orprocesses operate in organizational adaptation, thuspointing toward a theoretical modification ofneo-Darwinism that embraces both adaptation and naturalselection in a general, unified theory.     

Changes in Income Concentration: Taxes or Macroeconomic Conditions?

We examine the relative importance of tax rates and macroeconomic fluctuations in explaining the share of national adjusted gross income (AGI) reported by the top 0.5% of all taxpayers. Results indicate that cutting the top income or capital gains tax rate would increase the top AGI share but not by enough to increase revenues. The preponderance of evidence suggests that the top AGI share is affected more by the capital gains tax rate than by the income tax rate but that real gross domestic product fluctuations have even larger effects.     

ECONOMIC GLOBALIZATION AND WOMEN'S STATUS IN THE LABOR MARKET:

This study examines the effects of economic globalization on occupational sex segregation and occupational inequality. A theory of global economic restructuring and its impact on the quality of women's work suggests that national integration into the world economy significantly expands opportunities for women in the workplace but does not remove barriers to women's advancement or ameliorate the predominance of low-paying, menial jobs held by women. Two measures of gender occupational differentiation are employed as dependent variables in cross-sectional OLS regression analyses of fifty-six countries using data from 1970–1990. Results indicate that global economic forces reduce occupational sex segregation and inequality. However, these effects are determined by a country's world system position and region. The analyses illustrate that global economic restructuring is a gendered process that transforms and builds upon existing gender inequalities. Therefore, the inclusion of global structural characteristics into comparative research on occupational sex differentiation is essential.     

The Prospects for Digital Radio

Digital audio broadcasting is a major innovation in radio, one that is at its most advanced in Europe. It has the potential to deliver high-quality audio reception and to increase significantly the capacity of the radio spectrum, with the possibility of an expansion of both the range and diversity of radio programming. Nevertheless, in the UK and elsewhere it remains relatively unknown and under-adopted in comparison with other consumer technologies like digital television. This article examines the origins of digital radio, and considers how this technology is expected to become a mass communications technology, eventually supplanting analogue radio. However, in its present form, there is little that is novel currently being offered on digital radio, and the economic and political contexts in which it is being developed may encourage further concentration of ownership and reduce diversity of choice in listening. Unlike previous innovations then, such as FM broadcasting, there appear to be few compelling advantages of digital radio that will persuade listeners to adopt this new technology. If this new technological system is to succeed, alternative uses must be found for it, and one area for which it might be suited is mobile data communications. The article concludes by suggesting that this might mean that radio becomes of secondary importance to this potentially lucrative application of digital audio broadcasting technology.     

Markov Chain Monte Carlo in small worlds

As the number of applications for Markov Chain Monte Carlo (MCMC) grows, the power of these methods as well as their shortcomings become more apparent. While MCMC yields an almost automatic way to sample a space according to some distribution, its implementations often fall short of this task as they may lead to chains which converge too slowly or get trapped within one mode of a multi-modal space. Moreover, it may be difficult to determine if a chain is only sampling a certain area of the space or if it has indeed reached stationarity. In this paper, we show how a simple modification of the proposal mechanism results in faster convergence of the chain and helps to circumvent the problems described above. This mechanism, which is based on an idea from the field of “small-world” networks, amounts to adding occasional “wild” proposals to any local proposal scheme. We demonstrate through both theory and extensive simulations, that these new proposal distributions can greatly outperform the traditional local proposals when it comes to exploring complex heterogenous spaces and multi-modal distributions. Our method can easily be applied to most, if not all, problems involving MCMC and unlike many other remedies which improve the performance of MCMC it preserves the simplicity of the underlying algorithm.     

I'm OK, You're (Not) OK: The Private Welfare State in the United States

The American welfare state has been premised on the mixture of substantial private, tax‐subsidized benefits rather than on more universalistic public benefits. That pattern is in some ways being undermined as private pension plans are increasingly going bankrupt and firms reduce the benefits they provide employees. On the other hand, however, the current Bush administration is attempting to enhance the private sector role by allowing individuals to invest at least a part of their social insurance contributions into private savings plans. These changes may in the end increase the role of the public sector as a regulator and underwriter at the same time that attempts are made to minimize public sector involvement.