Water Transportation Industry Research Articles

The stock market perception of industry risk and microeconomic factors: The case of the US water transportation industry versus other transport industries

This paper undertakes a comparative analysis of the stock market perception of risk of U.S.-listed water transportation and other transport sectors such as air transportation, rail transportation, trucks, and other related industries such as electricity, gas, petroleum refining and real estate over the period July 1984–June 1995. This is done by relating cross-sectional differences in the returns of the companies in each industry to the stock market and to the following set of micro-economic factors: market value of equity; book to market value of equity ratio; earnings to price ratio; asset to market value of equity; and asset to book value of equity. The Seemingly Unrelated Regression methodology (SUR) is employed to estimate the above relationships due to its advantages over ordinary least squares. Our findings reveal that the water transportation industry is the only transportation industry which exhibits lower systematic risk than the market and that the asset-to-book ratio, along with the market, has explanatory power over its cross-sectional returns. Also, the micro factors which are significant in explaining stock returns vary between industries.

Exposure to potential occupational asthmogens: prevalence data from the National Occupational Exposure Survey.

Few data are available about the prevalence of occupational exposures to agents which can cause occupational asthma or aggravate preexisting asthma (asthmogens). Using potential occupational exposure data from the National Occupational Exposure Survey (NOES) of 1980-1983, we investigated the number of asthmogen exposures, asthmogen-exposure(s) per production worker, and unprotected occupational asthmogen exposures in different industries and occupations. Data for the entire United States were used to generate estimates of occupational exposure at two selected state and local levels. It was estimated that 7,864,000 workers in the surveyed industries were potentially exposed to one or more occupational asthmogen(s) in the United States. The average number of observed potential exposures per asthmogen-exposed worker was 4.4, and varied from 11.9, in the Water Transportation industry, to 1.2 in Local and Suburban transportation. The largest number of observed potential exposures was recorded in the Apparel and Other Finished Products (garment) industry. This work and further analyses using this approach are expected to contribute to a better understanding of the epidemiology of occupational asthma, and to serve as a guide to target future occupational asthma surveillance efforts.