Using a dual-frame design to improve phone surveys on political attitudes: developing a weighting strategy for limited external information in Hong Kong

Quality & Quantity - In recent years, rapid increases in mobile phone ownership and decreases in landline users have led to potential biases in landline phone survey estimations. Mobile-only...     

The Impact of Institutional Differences on Derivatives Usage: a Comparative Study of US and Dutch Firms

This paper examines the influence of institutional differences on corporate risk management practices in the USA and the Netherlands. We compare results to surveys in each country using a strategy that corrects for differences over industry and size classes across the Dutch and US samples. We document several differences in the firms’ uses and attitudes towards derivatives and attempt to attribute them to the differences in the institutional environments between the USA and the Netherlands. We find that institutional differences appear to have an important impact on risk management practices and derivatives use across US and Dutch firms.     

Dynamical modelling of an activated sludge system of a petrochemical plant operating at high temperatures.

The Mexican petrochemical industry, Morelos S.A. de C.V., is one of the biggest and more important petroleum industries in Mexico and Latin America. It has an activated sludge system to treat its wastewater flow, which is approximately 7,000 m3/d. The wastewater contains volatile organic carbon substances classified as toxics. The old surface aeration system was changed for fine bubble diffusers; however, one major drawback of the new aeration system is that the temperature in the bioreactor has increased due to the compression of the air, which at the compressor exit reaches 85 degrees C. This effect results in the temperature in the bioreactor attaining 32 degrees C during the fall, whereas in the spring and summer, the bioreactor temperature reaches higher values than 40 degrees C. The high temperatures reduce the microorganism activity and cause a higher volatilisation rate of volatile compounds, among other effects, which affect the performance of the biological treatment. This work was performed to obtain a better modelling of the wastewater treatment from the petrochemical industry. The model describes the effect of the temperature on the performance of the biological treatment. The model was obtained from tests that were carried out in laboratory reactors with 14 L capacity, which were operated at different temperatures (from 30 to 45 degrees C), with the same wastewater and conditions as the actual system.     

Health, Government, and Irving Fisher

A bstract    This paper provides a few historical notes on government involvement in health, followed by a summary of the theoretical arguments that economists offer in its support. Irving Fisher's views and recommendations about health are examined in the light of today's perceptions concerning health, health economics, and health policy. The wide variety of roles that the U.S. and other governments currently play in health is reviewed, and the ability of economics to explain these roles is assessed. The consequences of government involvement for the health of populations, for expenditures on health care, and for political and social stability are examined. The paper concludes with an overview of new worldwide trends in health policy and some probable explanations for these trends.     

Where have all the traditional classroom settings gone?—The use of large scale, public sector projects to illustrate a multidisciplinary approach to problem solving

This work describes the evolution and potential of an elective course for students who have already been exposed to the standard techniques of problem solving as presented in traditional courses. Students apply these techniques to large scale problems in directed mullidisciplinary project teams. In doing so, they are provided with a unique learning experience allowing them to serve as a resource to the community. Course projects described here include the promotion of a railing retail district; the formulation, implementation and monitoring of litter reduction strategies; the economic evaluation of using inmate labor to clean public areas; and economic comparisons of recycling strategies for used tires.     

Advertising with Subjective Horizontal and Vertical Product Differentiation

In this paper, we analyze the impact of advertising on markets wheresubjective horizontal and vertical product differentiation are important. A simple model showshow advertising can be used to create subjective horizontal and vertical differentiation.The model predicts that firms are likely to be symmetric when advertising creates subjective horizontaldifferentiation and that name and generic brands are most likely to coexist in markets whereadvertising creates subjective vertical differentiation. In all cases, the ability toadvertise creates distance between products which increases the market power of firms. Finally, severalreal world examples are used to illustrate the conditions under which the model is most relevant.     

Salmonid observations at a Klamath River thermal refuge under various hydrological and meteorological conditions

The Beaver Creek confluence with the main‐stem Klamath River was studied to assess salmonid use in a thermal mixing zone under various summer hydrological and meteorological conditions. Main‐stem flow releases from Iron Gate Dam ranged from 17 cms (615 cfs) to 37 cms (1320 cfs) during the study period and main‐stem water temperatures ranged from 19.5 to 26°C. A grid was constructed to define the thermal refuge as a system of cells. Temperatures were monitored using remote temperature loggers and fish counts were conducted using daytime snorkelling. Most juvenile salmonids were observed moving into the refuge when main‐stem temperatures exceeded 22–23°C. Salmonids in the thermal refuge did not necessarily seek the coolest water, but were generally located in habitats commensurate with species‐specific behavioural needs within their thermal tolerance range. Such ranges largely occurred within refuge areas. Variable meteorological conditions confounded observable biological thermal benefit to fish resulting from higher or lower main‐stem flows. Thermal regime dynamics indicated that under the hydrological and meteorological conditions observed, higher flows from Iron Gate Dam showed some ability to change the structure of the refuge area. It appeared that without the thermal refuge, main‐stem flows alone could not sustain the salmonid population because high water temperatures usually exceeded their published thermal tolerance limits. Copyright © 2007 John Wiley & Sons, Ltd.     

Collective Virtuosity in Organizations: A Study of Peak Performance in an Orchestra

abstract    The purpose of this paper is to build theory on peak performance at the group level. Peak performance transcends ordinary performance and is associated with a subjective experience in which one loses a sense of time and space as well as feels great joy and bliss. We chose to study this phenomenon at the group level through a methodology of participant observation in an orchestra. We found that groups can be transformed by their own performance in a reflexive process in which virtuosity, or individual peak performance, becomes collective. We offer a propositional model of collective virtuosity in organizations, and offer directions for further research.