A Discrete Time Parametric Model for the Analysis of Failure Time Data

This paper introduces a parametric discrete failure time model which allows a variety of smooth hazard function shapes, including shapes which are not readily available with continuous failure time models. The model is easy to fit, and statistical inference is simple. Further, it is readily extended to allow for differences between subjects while retaining the ease of fit and simplicity of statistical inference. The performance of the discrete time analysis is demonstrated by application to several data sets.     

‘MUSIC WHILE YOU WORK’: TEENAGE WOMEN IN THE AUSTRALIAN LABOUR MARKET, 1947 TO 1992

Teenage women have been particularly disadvantaged by the collapse of the youth labour market over the last 20 years. This article outlines the dimension of that problem, comparing the position young women held in the teenage labour market in the late 1940s with their position today. While the 1950s and 1960s saw growth in some areas of paid work for teenage women, the 1970s marked a watershed. With the major exception of saleswork in the retail industry and clerical work in banking, teenage women saw their place in the labour market dramatically shrink during that decade. Nearly 30,000 full-time jobs disappeared during the 1970s, to be replaced by nearly the same number of part-time jobs. The 1980s has seen these developments reach crisis proportions. In the late 1980s, nearly 40,000 clerical jobs were lost to teenage women, and again the only significant employment growth was in casualised service sector jobs, such as cashiers and sales workers. This article concludes by exploring the structural reasons behind these dramatic long-term changes.     

Laughter,the Best Mediation: Humor as Emotion Management in Interaction

Recent work in emotions and emotion management suggests that humor is a social phenomenon and serves an important purpose in interaction. That is, humor can be viewed as interpersonal emotion management, whose purpose is to manage the emotions of others as well as of the self. This article offers the following definition as an analytical tool: humor as emotion management is an expert cultural performance; which strengthens or restores the feeling norms of the situation and creates amusement in the self and others; generating positive sentiments among members of an interacting group by bonding them and/or reducing an external threat; often at the expense of some excluded person(s), event(s), or object(s).     

Assassination and leadership: Traditional approaches and historiometric methods

Research on the assassinations and attempted assassinations of leaders seems warranted, as leaders and their interactions with extreme followers (e.g., fanatics) and non-followers (e.g., assassins) can have tremendous consequences not only for the leaders but also their larger collectives (e.g., nations, social movements). Based on the traditional and established leadership approaches of power orientation and outstanding leadership, we explored whether particular types of leaders were more likely victims of assassinations and targets of assassination attempts. Using historiometric methods, we found that socialized as well as pragmatic and ideological leaders were the most frequent victims of assassinations; but personalized as well as pragmatic and ideological leaders were the most frequent targets of assassination attempts; and for U.S. Presidents, socialized charismatics were the most frequent victims of assassinations and targets of assassination attempts. Results regarding leader paranoia, regions of the world, and assassins operating alone or as a group in relation to assassinations and leadership approaches also are presented. Implications of these findings for future leadership research involving leaders and their extreme followers, non-followers, and larger collectives are discussed.     

Development and Application of a Stochastic Epidemic Model for the Transmission of Salmonella Typhimurium at the Farm Level of the Pork Production Chain

In previous work a deterministic model for the compartment level was built, taking into account the two different syndromes with which  Salmonella  Typhimurium appears at pig farms. Based on this model, a stochastic one was built in this work that simulated different compartmental sizes, taking into account compartments of 200 to 400 pigs. Multiple scenarios of starting conditions of infection (SCI) ranging from 0.25 to 100% were tested for each population size. The effect of each of these two factors on the probability of disease extinctions and the prevalence of each of the classes of the model and the risk groups of pigs were estimated. The results showed that the compartment population had an inverse effect on the probability of disease extinction. On the other hand, low SCI resulted in high levels of early extinctions reaching 45%, while higher SCI led to high levels of late extinctions. Early extinctions resulted in the absence of the pathogen from the compartment, while late extinctions did not assure it. This effect shows that reducing the population of the compartment combined with appropriate cleaning and good farming practices could have a positive effect in the reduction of the risk of introducing  S.  Typhimurium into the slaughtering procedure. On the other hand, the profile of seroprevalence at slaughter age allows for risk characterization of the farm, given the relative stability and the small variation for higher SCI.     

A Time‐Dependent Risk Assessment for Broken Compact Fluorescent Lamps

Environmental Protection Agency (EPA) ambient air quality guidelines are meant to limit long‐term exposures of toxins to safe levels. Unfortunately, there is little guidance for what constitutes a safe level from a one‐time (or very infrequent) short exposure(s). In the case of mercury, a review of the derivation of the EPA ambient air quality standard shows that it implicitly assumes a tissue burden model. The time dependence of the tissue burden is commonly described in terms of a half‐life, a modeling assumption that presumes that the decline in the tissue burden after a single exposure can be approximately described as an exponential decay. In this article, we use a simple exponential tissue burden model to derive a time‐dependent no observable adverse effect level (NOAEL) for mercury concentrations in air. The model predicts that tissue body burden will asymptotically approach the EPA air quality level for long exposure times, and reach workplace standard levels for exposures of a few hours. The model was used along with data on mercury levels from experimental work done by the Maine Department of Environmental Protection to evaluate the risks from a broken compact fluorescent lamp in a residential setting. Mercury levels approached the NOAEL only when the debris was left in an almost sealed room. Normal common‐sense cleaning measures: removal of debris to an outside area, and ventilation of the room for several minutes, reduced exposures to less than 1% of the NOAEL.     

Online bin packing of fragile objects with application in cellular networks

We study a specific bin packing problem which arises from the channel assignment problems in cellular networks. In cellular communications, frequency channels are some limited resource which may need to share by various users. However, in order to avoid signal interference among users, a user needs to specify to share the channel with at most how many other users, depending on the user’s application. Under this setting, the problem of minimizing the total channels used to support all users can be modeled as a specific bin packing problem as follows: Given a set of items, each with two attributes, weight and fragility. We need to pack the items into bins such that, for each bin, the sum of weight in the bin must be at most the smallest fragility of all the items packed into the bin. The goal is to minimize the total number of bins (i.e., the channels in the cellular network) used. We consider the on-line version of this problem, where items arrive one by one. The next item arrives only after the current item has been packed, and the decision cannot be changed. We show that the asymptotic competitive ratio is at least 2. We also consider the case where the ratio of maximum fragility and minimum fragility is bounded by a constant. In this case, we present a class of online algorithms with asymptotic competitive ratio at most of 1/4+3r/2, for any r>1. A preliminary version of this paper appeared in Proc. of Workshop on Internet and Network Economics (WINE’05, pp. 564–573). The research of W.-T.C. was supported in part by Hong Kong RGC grant HKU5172/03E. The research of F.Y.-L.C. was supported in part by Hong Kong RGC Grant HKU7142/03E. The research of D.Y. was supported by NSFC (10601048). The research of G.Z. was supported in part by NSFC (60573020).     

Disaffected Loyalties in a Changing Contractual Environment

In this paper we examine the effects of the changing employee-employer relationship on loyalty – a construct we developed along Hirschman’s model. The impact on perceptions of loyalty during a downsizing is assessed using a design that manipulates HRM policies toward the use of temporary employees, retraining, employee voice, seniority and community coordination. We introduce ideological orientation as a variable that will have direct and indirect affects. Both MBA students and managers (N = 269) participated in the study. All HRM policies and ideological orientations have direct affects; in addition some indirect effects for ideological orientation emerged. This revised version was published online in July 2006 with corrections to the Cover Date.     

Remuneration Committees,Pay Consultants and the Determination of Executive Directors' Pay

This paper explores how Board Remuneration Committee (Remco) decisions about executive pay are influenced by pay consultants. Drawing on resource dependency theory and case study evidence from five companies, the paper illuminates the complexities of the pressures and processes confronting both Remcos and pay consultants in the determination of executive pay awards. In contrast to ‘managerial power’ arguments, it demonstrates that the Remcos are proactive in managing pay policy, conscientious in seeking to ensure that pay is appropriate and not over‐generous, and that pay consultants are independent and take their instructions entirely from the Remco. Nevertheless, Remcos' understandings of the wider pay environment, informed by the comparative data supplied by pay consultants, constructs a climate in which the Remcos come to perceive a need for periodic upward pay adjustments to ensure that executive remuneration is consistent with external benchmarks if they are to avoid recruitment and retention problems.