Influence of Safety Measures on the Risks of Transporting Dangerous Goods Through Road Tunnels

Quantitative risk assessment (QRA) models are used to estimate the risks of transporting dangerous goods and to assess the merits of introducing alternative risk reduction measures for different transportation scenarios and assumptions. A comprehensive QRA model recently was developed in Europe for application to road tunnels. This model can assess the merits of a limited number of "native safety measures." In this article, we introduce a procedure for extending its scope to include the treatment of a number of important "nonnative safety measures" of interest to tunnel operators and decisionmakers. Nonnative safety measures were not included in the original model specification. The suggested procedure makes use of expert judgment and Monte Carlo simulation methods to model uncertainty in the revised risk estimates. The results of a case study application are presented that involve the risks of transporting a given volume of flammable liquid through a 10-km road tunnel.     

The Incremental Group Testing Model for Gap Closing in Sequencing Long Molecules

In this paper, we propose the incremental group testing model for the gap closing problem, which assumes that we can tell the difference between the outcome of testing a subset S, and the outcome of testing S {x}. We also give improvements over currently best results in literature for some other models.     

Perceived Risks from Radiation and Nuclear Testing Near Semipalatinsk, Kazakhstan: A Comparison Between Physicians, Scientists, and the Public

Determining the difference in perception of risk between experts, or more educated professionals, and laypeople is important so that a potential hazard can be effectively communicated to the public. Many surveys have been conducted to better understand the difference between expert and public opinions, and often laypeople exhibit higher perceptions of risk to hazards in comparison to experts. This is especially true when health risk is due to radiation, nuclear power, and nuclear waste. This article focuses on one section of a risk perception survey given to two groups of individuals with a more specialized education (scientists and physicians) and laypeople (villagers) in the Semipalatinsk region of Kazakhstan. All of these groups live near the former Soviet nuclear test site. Originally, it was expected that the scientists and physicians would have similar perceptions of radiation risk, while the public perceptions would be higher, but this was not always the case. For example, when perceptions of risk pertain to the health impacts of nuclear testing or the dose-response nature of radiation exposure, the physicians tend to agree with the laypeople, not the scientists. The villagers are always the most risk-averse group, followed by the physicians and then the scientists. These differences are likely due to different frames of reference for each of the populations.     

Knowledge Management Systems in Multinational Corporations: Typology and Transitional Dynamics

Knowledge Management Systems (KMSs) are becoming part of the agenda in many of today's leading firms. Through in-depth case studies of seven multinational companies (MNCs), examined over a period of four years, we identify four distinctive types of KMS - Fragmented, Content-based, Process-based and Capability-based - and their characteristics. These characteristics include both the structure, dimension and flow of the knowledge itself, and the staffing, training and reward systems in place to support the KMS. Relevant organisational factors influencing KMS design and implementation include the level of resource commitment by the headquarters, the structure of the firm, and the distribution of roles between headquarters and subsidiaries. Key external influences include the degree of environmental change and pressures to follow industry norms in technology investment. Our empirical evidence suggests that while some MNCs adopt the same type of KMS for relatively long periods of time, others transit between different KMS types. Moreover, transitions between types may follow either an increased resource commitment and augmented KMS sophistication, or a decreased resource commitment and reduced KMS complexity. Insights from the strategy-structure-process and change management literatures are utilised to examine these transitions between KMS types. Key lessons for MNC managers are provided in relation to both the initial adoption of a KMS and the handling of transitions between different systems.     

Delayed Adulthood,Delayed Desistance? Trends in the Age Distribution of Problem Behaviors

As the transition to adulthood becomes more protracted and less orderly, fewer young people occupy adult roles and experience the social control associated with these roles. One might therefore expect behaviors associated with the teenage years to spill over into older age groups, reflecting postponed entrance into full social adulthood. We test this hypothesis by examining trends over time in the age distribution of crime, substance use, and violent death. We find little evidence that behaviors typical of adolescence are moving upward to older ages. Although the achievement of adult roles is being pushed to older ages, this stretching of the transition to adulthood is not reflected in the observed patterns of substance use, violent death, and arrests.     

Undergraduate Women in Science and Engineering: Effects of Faculty,Fields, and Institutions Over Time*

Objective. Taking an institutional approach to the determinants of outcomes for women in science and engineering, we examine the effects on women's percentages among undergraduate majors and among degree recipients of four basic factors: (1) the percentage of faculty who are women in the students' major science/engineering area; (2) the students' disciplines (biology, physical sciences, and engineering); (3) the type of institution in which students are enrolled (“Research I” vs. others); and (4) a time trend (1984–2000). Method. We use longitudinal, multivariate, and multi‐institutional data from the Integrated Postsecondary Data System (IPEDS) and from a mail survey of registrars. Results. Over the observation period, the women's percentages have risen steadily. The effects of disciplines and departments are stronger than those of institutions. Especially notable is that the percentages of women among undergraduate science/engineering majors and degree recipients are associated with the percentages of women among the faculty in these fields. Conclusion. The findings contribute empirically to the discussion about the effects of “role models” for the participation and performance of women in science and engineering—and point to the strong effects of departments, compared to institutions, in accounting for degrees awarded to undergraduate women.