Estimating the Ozone Depletion Potential of Methyl Bromide

Ozone depletion potential (ODP) represents the cumulative ozone depletion induced by a particular halocarbon relative to a reference gas (usually trichlorofluoromethane, CFC-11). We focus on ODP estimation for methyl bromide. Previous attempts at its estimation have assumed that components of the ODP equation are lognormally distributed. By considering a wide range of modeling scenarios, we show that this restriction (which is based on computational convenience rather than experimental evidence) has obscured the true uncertainty in the ODP value. Moreover, when publishing point estimates for the ODP value, previous authors have given either mean or median values. We submit that a more appropriate choice for a point estimate is the mode since the distribution of ODP is skewed and since the mode is by definition, the most likely value. For each modeling scenario considered, modal values are given. In general, we find these ODP point estimates are considerably lower than those published elsewhere.     

Empowering Patients Through Access to Information

The United States federal government is in the midst of an e- government revolution characterized by a shift from paper-based citizen-government interactions to electronic-based interactions. Driven by the demands of citizens and supported by the President and Congress, federal departments are redesigning the look and feel of their Internet presences, moving away from traditional bureaucracy- centred presentation of information to more usable citizen-centred presentations. The Department of Health and Human Services (HHS), the USA's principal federal agency tasked with protecting the health of all Americans and providing essential human services, has undertaken a massive reorganization of its e-health enterprise. The most publicly visible component of this reorganization is the hhs.gov portal website. This desperately needed portal - usability testing indicated that more than 60 per cent of visitors to the Department's original website failed to find the information they sought - provides easy access to the wealth of HHS information and links its diverse operating agencies. The new HHS portal simplifies citizen access to the Department by: decompartmentalizing information by removing content from bureaucratic silos² and rearranging it in a natural navigation scheme; tuning content and navigation features to ensure that all users have access to information tailored for them; presenting content in appropriate and citizen-preferred formats; and complying with federal accessibility regulations for blind and vision-impaired users. This paper presents a series of lessons learned during the development of the HHS portal, and results of usability testing to determine what common design features present accessibility problems particular to the blind and vision-impaired communities. These discussions of practical avenues to improving the accessibility and usability of e-health websites through appropriate and effective information designs are followed by our thoughts on the future of Internet architectures and the limitations of 'layering' technologies when striving for universal accessibility.     

Fertility and economic activity of women in Guatemala city, 1964

Data from a five percent census sample reveal that in Guatemala City in 1964 economically active women, especially domestic servants, had lower cumulative fertility than inactive women, partly because larger proportions of them had never married and were childless. However, even among ever married mothers there was a substantial differential, which was not due to differences in age at first birth. With respect to all women, cross tabulation and regression analysis show that age, marital status and educational attainment were more strongly associated with fertility than was activity status, but the latter also had a significant net association. Selection for sterility was not likely. Being contrary to expectations expressed in the literature, the very low fertility of the domestics received further attention. Live-in domestics had considerably lower fertility than those who lived out, which was also the case in the United States in 1960. These data and other evidence strongly suggest that this differential is due to a widespread employer preference for single or childless women. The concept of role incompatibility is therefore inapplicable to domestic servants. These findings add to the considerable evidence showing lower fertility among economically active women in large urban places in Latin America.     

Applied general equilibrium modeling for long-term energy policy in Germany

The energy model is based on an extension of applied general equilibrium models of the Leontief input-output type, first implemented by Hudson and Jorgenson (1974). One objective of our project is to choose specifications of sectoral production and cost functions that permit us to estimate the unknown parameters of the price functions and input demand functions from a single input-output table in ten energy and 35 non-energy industries. Our second objective is to determine the price for capital and labor as well as the components of final demand endogenously instead of using a separate growth model as an engine for the economic development. Our third objective is to combine the concept of price-dependent substitution within the input structure with the concept of vintage coefficients for the latest plants. By this we incorporate into the input-output analysis the effect on growth as a result of investment, the effect on capacity as a result of new plants, and the effect on prices as a result of new technologies. An application of the model shows the long-term impact on growth and prices under alternative technologies in the electricity industry (nuclear or coal-fired power plants).     

Boards of directors in nonprofit organizations do they follow a life-cycle model?

In this study the authors used data from a survey of Canadian nonprofit organizations to empirically test hypotheses derived from models of nonprofit board “life cycles.” The authors suggest that while formal structural elements of board behavior change in the manner suggested by life-cycle models, the more enacted or behavioral aspects of nonprofit boards do not. The data further suggest caution in the use of life-cycle or age-dependent models to either explain or guide nonprofit board behavior.     

CONVERGENT SERIES EXPRESSIONS FOR INVERSE MOMENTS OF QUADRATIC FORMS IN NORMAL VARIABLES

Using relatively recent results from multivariate distribution theory, a direct approach to evaluating the inverse moments of a quadratic form in normal variables is proposed. Convergent infinite series expressions involving the invariant polynomials of matrix argument are obtained. The solution also depends upon a positive scalar which is arbitrarily chosen. For the solution to converge an upper bound upon this scalar is derived.