A Comparison of Methods for Estimating the Benchmark Dose Based on Overdispersed Data from Developmental Toxicity Studies

Developmental anomalies resulting from prenatal toxicity can be manifested in terms of both malformations among surviving offspring and prenatal death. Although these two endpoints have traditionally been analyzed separately in the assessment of risk, multivariate methods of risk characterization have recently been proposed. We examined this and other issues in developmental toxicity risk assessment by evaluating the accuracy and precision of estimates of the effective dose ( ED ₀₅) and the benchmark dose ( BMD ₀₅) using computer simulation. Our results indicated that different variance structures (Dirichlet-trinomial and generalized linear model) used to characterize overdispersion yielded comparable results when fitting joint dose response models based on generalized estimating equations. (The choice of variance structure in separate modeling was also not critical.) However, using the Rao-Scott transformation to eliminate overdispersion tended to produce estimates of the ED ₀₅ with reduced bias and mean squared error. Because joint modeling ensures that the ED ₀₅ for overall toxicity (based on both malformations and prenatal death) is always less than the ED ₀₅ for either malformations or prenatal death, joint modeling is preferred to separate modeling for risk assessment purposes.     

An exploratory study of the influence of the IS function and organizational context on business process reengineering project initiatives

To help evaluate the risk of process reengineering failure and enhance the prospect of its success, three potential sources of influence on BPR initiatives and success are examined in this study. These include the innovative capacity of the organization, IS maturity and strategy-IS interface. It was found that while factors related to IT maturity and influence such as experience in mainframe and client/server computing may facilitate the decision to reengineer, they are not critical in the later stages of the initiative. On the other hand, factors having significant relationships beyond the initial decision include variables pertaining to innovative capacity of the organization and strategy-IS interface. These findings suggest that technical IT competence as a critical enabler is necessary but not sufficient for reengineering success. Based on study findings regarding the innovative capacity of the organization, guidelines for reengineering risk assessment are proposed. In addition, implications of the findings, limitations of the study and opportunities for further research are also discussed.     

Critical Radionuclide/Critical Pathway Analysis for the U.S. Department of Energy's Savannah River Site

Many different radionuclides have been released to the environment from the Savannah River Site (SRS) during the facility's operational history. However, as shown by this analysis, only a small number of the released radionuclides have been significant contributors to potential doses and risks to off-site people. This article documents the radiological critical contaminant/critical pathway analysis performed for SRS. If site missions and operations remain constant over the next 30 years, only tritium oxide releases are projected to exceed a maximally exposed individual (MEI) risk of 1.0E-06 for either the airborne or liquid pathways. The critical exposure pathways associated with site airborne releases are inhalation and vegetation consumption, whereas the critical exposure pathways associated with liquid releases are drinking water and fish consumption. For the SRS-specific, nontypical exposure pathways (i.e., recreational fishing and deer and hog hunting), cesium-137 is the critical radionuclide.     

Boredom and social meaning

Meaning is necessary in social processes. An absence of meaning in an activity or circumstance leads to an experience of boredom. This is a restless, irritable feeling that the subject's current activity or situation holds no appeal, and that there is a need to get on with something interesting. Thus boredom emotionally registers an absence of meaning and leads the actor in question towards meaning. Boredom, then, is central to key social processes centered on questions of meaningfulness. Given the pervasive preconditions for boredom, release from boredom is a factor that explains characteristic social practices, including risk taking and intergroup conflict.     

Asymptotic Minimax Risk for the White Noise Model on the Sphere

Estimation of an unknown function on the unit sphere of the Euclidean space is considered. The function is observed in Gaussian continuous time white noise. Uniform norm is chosen as a loss function and exact asymptotic minimax risk is derived extending the result of Korostelev (1993). The exact asymptotic minimax risk is also given for the L ₂-loss, applying the result of Pinsker (1980).     

FDI’s Impact on Transitional Countries, Serbia as a Rational Choice: The FIAT-ZASTAVA Case

The privatization process and foreign direct investments (FDI) are among the most important economic issues in transitional countries. FDI has enormous influence on transitional countries that need serious structural changes. In this paper we will study FIAT’s decision to invest in the Serbian automotive industry. We will try to rationalize FIAT’s decision because Serbian car manufacturer ZASTAVA was not the only alternative for FIAT to invest in the Balkans. In order to justify FIAT’s decision we will apply the Mullins model of horizontal and vertical FDI, examine the importance of the cooperating history between two car manufacturers and compare macroeconomic conditions and Global Competitiveness of Serbia and Romania, which was the main alternative for FIAT. Finally, we will also try to explain why FIAT decided to announce the investment at the end of political campaign in Serbia when pools gave anti-European parties higher chances for victory, instead of waiting to see the outcome of the elections.

Structural Analyses Of The Quality Of Life Of Children At Risk

Quality of life (QOL) is usually assessed in terms of levels. This paper, in contrast, examines the structure of the quality of life of its subjects: two groups of children at risk, children who were kept at home and those who were removed from home. The social workers who made the decisions were asked to assess the children’s quality of life using Shye’s Systemic Quality of Life Model. The study’s main finding is that the QOL structure of the two groups of children differs both from the theoretical “ideal” (or “healthy” structure) and from each other. The QOL structure of the children who were kept at home was closer to the ideal than that of the children who were removed. The difference from the ideal in both groups is consistent with the fact that both groups of children at risk, whose QOL is compromised by definition. The greater proximity to the “ideal” of the QOL structure of the children who were kept at home suggests that the social workers who made the decisions viewed these children as having a healthier QOL than the children who were removed from home.