The EPQ with partial backordering and phase-dependent backordering rate

In previous work we established a closed-form optimal stocking strategy for an EPQ model with partial backordering at a constant rate β. Here we extend this work to allow for the possibility that the percentage of demand backordered will increase when production starts again. We show how our previous model can be adapted to find the optimal decision variable values for this new assumption and develop the condition that the initial value of β must meet for partial backordering to be optimal.     

Communicating risk to parents and those living in areas with a disaster history

This study explored how publics respond to risk communication in high probability but time-indeterminate natural disaster situations when parts of the area have been involved in a similar disaster before. An impending rockslide is expected to produce a tsunami in the fjord around Åknes in Norway. Waves may run up above sea level as high as 82 m or 269 ft. All residents (18 and older) of the four most threatened communities received a questionnaire to determine what they perceived to be useful risk information. Three hundred and eighty-two (43.6% of 875) responded. Results indicated that parents of children living within the tsunami risk zones perceived the risk information to be the most useful. Those who lived in communities that experienced a similar disaster in 1934 reported public meetings less useful than written or mediated information. Publics who lived in communities with such disaster history and those who were not parents posed special challenges in risk communication because they perceived information from the government agencies as lacking in usefulness. Therefore, committing the resources necessary to foster dialogues with a diversity of publics exposed to risk would be well served to fully understand the nature of risk communication responses, and to be able to save human lives.     

Building a statistical model to predict reactor temperatures

This paper describes the various stages in building a statistical model to predict temperatures in the core of a reactor, and compares the benefits of this model with those of a physical model. We give a brief background to this study and the applications of the model to rapid online monitoring and safe operation of the reactor. We describe the methods, of correlation and two dimensional spectral analysis, which we use to identify the effects that are incorporated in a spatial regression model for the measured temperatures. These effects are related to the age of the reactor fuel and the spatial geometry of the reactor. A remaining component of the temperature variation is a slowly varying temperature surface modelled by smooth functions with constrained coefficients. We assess the accuracy of the model for interpolating temperatures throughout the reactor, when measurements are available only at a reduced set of spatial locations, as is the case in most reactors. Further possible improvements to the model are discussed.     

WHITE ENROLLMENT IN NONPUBLIC SCHOOLS, PUBLIC SCHOOL RACIAL COMPOSITION, AND STUDENT PERFORMANCE

This research note presents preliminary research into the relationship between the racial composition of public schools in school districts and the percentages of white students in nonpublic schools in those districts. Specifically, we ask two questions: Is the enrollment of whites in non‐public schools associated with minority predominance in public schools? Is there an association between the enrollment of whites outside of the public school system and the academic performance of students in the public school system? Using two‐ and three‐level hierarchical linear models, we find that school districts that have more whites in nonpublic schools tend to contain public schools with larger percentages of minority students. Further, at both the school and individual levels, achievement test scores tend to be lower in districts in which white students tend to be enrolled outside of the public school system. In addition, the achievement gap between white and minority students tends to be greater in districts with relatively more students in nonpublic schools. These findings are consistent with the argument that the withdrawal of white students from the public school system is negatively related to academic achievement because it tends to concentrate minority students in public schools.     

Gender roles,HIV risk behaviors,and perceptions of using female condoms among college students

The purpose of this study was to examine relationships between gender roles and HIV risk behavior, and perceptions and acceptance of the female condom among college students (n = 410). It was hypothesized that high hyperfeminine females and high hypermasculine males – those adhering to traditional gender roles – would engage in more HIV risk behaviors, including alcohol and drug use and various sexual practices, than those with lower hyperfemininity and hypermasculinity. It was also hypothesized that higher hyperfeminine females as well as higher hypermasculine males would perceive the female condom more negatively and would be less likely to view the female condom as a viable form of protection in the future. It was also hypothesized that high hyperfeminine females and high hypermasculine males would not accept the female condom as an alternative form of protection. Implications for prevention interventions are discussed.     

HOW MANAGEMENT USERS VIEW INFORMATION SYSTEMS

The literature of management information systems suggests that substantial discord exists between management users and systems personnel. This paper describes the current attitudes of managers toward information systems and computers as reflected in seventy-five carefully structured interviews with managers from ten major companies. The author concludes that management user attitudes are quite favorable and do not reflect the predicted discord. In fact, the author believes that one of the major systems implementation problems of the future may be apathy rather than antipathy. The data collection was structured to indicate differences in attitudes on the part of users based on organizational level, functional area of work, type of activity, and type of environment.     

The Nature of Social Pasts and Their Use as Foundations for Situated Action

In this paper social pasts are considered to be foundations of everyday interpersonal life, including everyday situated action. We distinguish social pasts from culture by noting that the former involves recognition of specific joint acts and social placements while the latter involves recognition of ties to acts and placements in general. We further distinguish shared pasts–which refer to specific and previous joint acts or social placements that interactors constructed together–from common pasts–which refer to specific and previous joint acts or social placements that interactors constructed with others. We assess the importance of using either common or shared pasts in the course of completing and simplifying complex and everyday transactions so as to create an appearance of routine-ness in relation to constructing these acts.