Work experiences and marital interactions: Elaborating the complexity of work

Previous research suggests that work experiences affect family interactions and family processes but does not adequately specify the job characteristics that influence such family-level outcomes. This study examines relationships between the quality of marital interactions and a range of job characteristics including the level of enrichment provided by the job, job time demands, job pressure, schedule flexibility, and job insecurity. The sample consisted of 523 married full time employees at a major U.S. company. Multiple regression analysis indicated that these job characteristics significantly predict the quality of marital interactions. Some directly influenced the quality of marital interaction while the influence of others was moderated by the presence or absence of stressful household roles. Results suggest that characteristics workers' jobs, and not merely workers' reactions to them, are associated with family interactions and family processes.     

EFFECTIVENESS OF DROUGHT POLICIES FOR MUNICIPAL WATER MANAGEMENT1

During the 1976–77 drought, three principal mechanisms were used to reduce water use in Utah communities: price increases, maximum monthly use restrictions, and restrictions on outdoor watering times. A regression model was developed to explain observed changes in water use, with price, type of restriction, household size, and summer rainfall as independent variables. For an average system, a 1 percent increase in price would reduce water use by 0.07 to 0.09 percent. A 1 percent increase in outdoor watering time restriction reduces use by 0.064 to 0.075 percent. A 1 percent increase in quantity restrictions leads to a reduction in water use of 0.014 to 0.054 percent. The effectiveness of rationing policies is influenced by system characteristics. For example, outdoor watering time restrictions were less effective in systems with above average household size and below average monthly use.     

A TAU-LIKE TEST FOR TREND IN THE PRESENCE OF MULTIPLE CENSORING POINTS1

ABSTRACT: A common problem arises in testing for trends in water quality when observations are reported as “less than detection limit.” If a single detection limit is used for the entire study, existing non-parametric statistical methods, modified for ties, are applicable. If, however, the detection limit varies during the course of the study, resulting in multiple detection limits, then the commonly used trend detection methods are not appropriate. A statistic similar to Kendall's tau, but based on expected ranks, is proposed. Monte Carlo simulations show that the normal approximation to the distribution of this statistic is quite good, even for small samples and a large proportion of censored observations. The statistic is also shown to have greater power than the ad-hoc method of treating all observations less than the target censored observation as tied.     

AN APPLICATION OF INVESTMENT TIMING ANALYSIS: DUAL WATER SYSTEMS1

ABSTRACT: A general methodology to study the economics of dual water systems (defined here as a separate distribution system for untreated low quality local surface Water for outdoor municipal water supply) is summarized and the application of the method to a rapidly growing city is presented. In the first step, a cost-benefit criterion for evaluating dual systems is developed. The criterion is then extended to a dynamic case where the population to be served increases with time and where the dual system is allowed to expand. The optimal investment time to introduce the dual water supply project is obtained by maximizing social welfare. The model is applied to the city of West Jordan, Utah, where a dual system is currently being proposed. Model results indicate that for the city as a whole dual supply is not economically feasible. However, when the model is applied to a part of the city, it is found feasible and the optimal time to initiate the project would be in the year 1989.     

Development of a bird integrity index: using bird assemblages as indicators of riparian condition

We describe the development of a bird integrity index (BII) that uses bird assemblage information to assess human impacts on 13 stream reaches in the Willamette Valley, Oregon, USA. We used bird survey data to test 62 candidate metrics representing aspects of bird taxonomic richness, tolerance or intolerance to human disturbance, dietary preferences, foraging techniques, and nesting strategies that were affected positively or negatively by human activities. We evaluated the metric responsiveness by plotting each one against a measure of site disturbance that included aspects of land use/land cover, road density, riparian cover, and stream channel and substrate conditions. In addition, we eliminated imprecise and highly correlated (redundant) metrics, leaving 13 metrics for the final index. Individual metric scores ranged continuously from 0 to 10, and index scores were weighted to range from 0 to 100. Scores were calibrated using historical species information to set expectations for the number of species expected under minimally disturbed conditions. Site scores varied from 82 for the least disturbed stream reach to 8.5 for an urban site. We compared the bird integrity index site scores with the performance of other measures of biotic response developed during this study: a fish index of biointegrity (IBI) and two benthic macroinvertebrate metrics. The three assemblages agreed on the general level of disturbance; however, individual sites scored differently depending on specific indicator response to in-stream or riparian conditions. The bird integrity index appears to be a useful management and monitoring tool for assessing riparian integrity and communicating the results to the public. Used together with aquatic indicator response and watershed data, bird assemblage information contributes to a more complete picture of stream condition.     

Ranking the benefits of biodiversity: an exploration of relative values

Public concern about the alarmingly high rate of biodiversity loss has not been matched by public willingness to bear boundless costs to stem the tide of extinction. Because resources for conservation are limited, setting conservation priorities to use those resources effectively is crucial. To do so in a way that addresses people's most pressing concerns about biodiversity loss, managers and policy makers must understand those concerns. This study investigates preferences for an array of benefits associated with biodiversity and wildlife and the relative importance to people of each. A survey was administered to a sample of the US population to explore public preferences for types of benefits often associated with biodiversity: utilitarian (commodity and recreation), ecological (certain and uncertain), aesthetic, symbolic, and humanistic. Respondents were asked to rank hypothetical species presented in choice sets of three species, each described simply in terms of one type of benefit. A rank-ordered multinomial logit model was estimated to establish a ranking of the benefits and evaluate the sensitivity of the ranking to socio-demographic variables. The means of the sample predictions indicated the relative importance of each type of benefit. Confidence intervals were constructed to evaluate the extent to which the ranks could be distinguished from one another. Ecological functions were most important to survey respondents; commodity-based benefits and human attributes were of moderate importance; and recreation, aesthetics, and symbolic references in literature and art appeared to be least important.     

Advancing the use of an innovative cleanup technology: Case study of Lasagna™

Originated from a recognized need for significantly more effective technologies for soil cleanup, the Lasagna^TM project provides an interesting case study in which industry, government, and academia successfully collaborated to rapidly advance the technology from the laboratory to the field. Called Lasagna^TM because of its layered configurations, the technology combines electrically induced contaminant transport in soils, treatment in place, and geotechnical methods to achieve completely in situ clean-up of contaminated soils. Experiences with respect to the partnership, the development of technology and its current commercialization status are described.     

Optimal stabilization of the copper market: The problem of information

This paper investigates the scope for stabilizing commodity prices by buffer stock interventions. Optimal control is used, rather than simulation, to evaluate the scope for intervention at best. Applications to a world copper market model show that substantial but extensive gains to stabilization are possible. These gains cannot be realised by traditional bandwidth decision rules. An important difficulty is setting the level at which prices should be stabilized. The lack of this information severely reduces the achievable gains.