Time series models with asymmetric innovations

We consider AR(q) models in time series with asymmetric innovations represented by two families ofdistributions: (i) gamma with support IR : (0, ∞), and (ii) generalized logistic with support IR:(-∞,∞). Since the ML (maximum likelihood) estimators are intractable, we derive the MML (modified maximum likelihood) estimators of the parameters and show that they are remarkably efficient besides being easy to compute. We investigate the efficiency properties of the classical LS (least squares) estimators. Their efficiencies relative to the proposed MML estimators are very low.     

A generalized drop-the-loser rule for multi-treatment clinical trials

Urn models are popular for response adaptive designs in clinical studies. Among different urn models, Ivanova's drop-the-loser rule is capable of producing superior adaptive treatment allocation schemes. Ivanova [2003. A play-the-winner-type urn model with reduced variability. Metrika 58, 1–13] obtained the asymptotic normality only for two treatments. Recently, Zhang et al. [2007. Generalized drop-the-loser urn for clinical trials with delayed responses. Statist. Sinica, in press] extended the drop-the-loser rule to tackle more general circumstances. However, their discussion is also limited to only two treatments. In this paper, the drop-the-loser rule is generalized to multi-treatment clinical trials, and delayed responses are allowed. Moreover, the rule can be used to target any desired pre-specified allocation proportion. Asymptotic properties, including strong consistency and asymptotic normality, are also established for general multi-treatment cases.     

Successful entrepreneurship in Hong Kong

The business performance of Chinese firms throughout the world is generally regarded as outstanding. It is also generally accepted in the literature that entrepreneurial business firms play a significant role in economic development of countries at every level of industrialization. Even though entrepreneurship is a major influencing factor for economic growth and development, the interpretation of this factor is still debatable. This paper examines the following factors which might influence the emergence of entrepreneuship: (1) economic; (2) non-economic; and (3) psychological. It then relates these factors to Chinese culture in an attempt to explain the apparent outstanding entrepreneurial skills of the Chinese people. As for economic factors, in Hong Kong the free open market and voluntary exchange provide freedom for distribution of income which in turn allows business practitioners to retain profits and accumulate wealth. Non-economic factors in Hong Kong include is blocked upward mobility in political channels in the colonial environment. This causes the Chinese to use economic mobility as an alternative. Psychological factors include the viewpoint that Chinese are more concerned about a sense of personal or individual achievement, power and influence than other cultures. This causes the Hong Kong Chinese to shift their achievement drives to business success and this encourages entrepreneurship.     

A stakeholder perspective on process improvement behaviours: delivering the triple bottom line in SMEs

Abstract

The primary focus of operations management is to add value through operational processes. Considerable attention has been given to using process improvement (PI) techniques to reduce costs and time, in order to develop a competitive advantage for the wider organization. However, this narrow definition of value at times overlooks the triple bottom line (TBL) which can result in a number of unintended consequences, specifically issues related to environmental and social measures of performance. To address this, a stakeholder theory lens will be used to analyze PI activities within the context of small and medium-sized enterprises. The TBL will be used to complement the stakeholder perspective, to interpret the benefits that are realized from PI activities. This article highlights both the direct benefits from PI as well as more indirect benefits realized by involving a selection of salient stakeholders in PI. It will show how a developed view of PI can provide an important mechanism for delivering improvements to a firm’s TBL. The work concludes by highlighting the contributions made to both PI practice and stakeholder theory, while acknowledging the need for more research on PI, both from a stakeholder perspective and how it impacts a firm’s TBL.     

Come one, come all

Aging is a complex process that involves the gradual functional decline of many different tissues and cells. Gene expression microarray analysis provides a comprehensive view of the gene expression signature associated with age and is particularly valuable for understanding the molecular mechanisms that contribute to the aging process. However, because of the stochastic nature of the aging process, animals of the same chronological age often manifest great physiological differences. Therefore, profiling the gene expression pattern of a large population of aging animals risks either exaggerating or masking the changes in gene expression that correspond to physiological aging. In a recent paper, Golden and Melov surveyed the gene expression profiles of individual aging Caenorhabditis elegans, hoping to circumvent the problem of variability among worms of the same chronological age. This initial analysis of age-dependent gene expression in individual aging worms is an important step toward deciphering the molecular basis of physiological aging.     

An Integrative Review of Employee Voice: Identifying a Common Conceptualization and Research Agenda

Employee voice has been studied across a diverse range of disciplines, generating an extensive body of literature on the topic. However, its conceptualization across the disciplines has differed, resulting in a lack of integrative theories and frameworks on employee voice. The main objective of this paper is to conduct a multidisciplinary review of the academic research on employee voice, to show where there is an opportunity to adopt and adapt the findings and research on employee voice within alternate disciplines, and to demonstrate how this may lead to more common ground in the conceptualization of employee voice. This review focuses on an analysis of the Human Resource Management/Employment Relations and Organizational Behaviour disciplines' conceptualization of employee voice, beginning with the identification of where the disciplines diverged in their concept and study of employee voice. Further, it maps their similarities and differences, on the basis of motive, content, mechanism, target and management of voice. Finally, it identifies opportunities to incorporate the alternate disciplinary perspective and proposes a conceptual model, which addresses the blind spots in each discipline. It is proposed that the consideration of formal and informal employee voice in future studies will enable the better integration of voice research.     

A Note on the Modified Likelihood Ratio Test for Homogeneity in Beta Mixture Models

This article presents a note on the modified likelihood ratio test for homogeneity in beta mixture models. Under consistency of the penalized maximum likelihood estimators, the limiting distribution of the test statistic converges to the chi-bar-squared distributions. The statistic degenerates to zero with a weight due to the negative definiteness of a complicated random matrix. The probability that this matrix is negative definite is related to the parameter values under the homogeneity hypothesis. The dependency pattern enables the introduction of an upper bound on the asymptotic null distribution. Simulation study is investigated to verify the accuracy of the results.     

Assessing readiness to work from a stages of change perspective: implications for return to work

The Lam Assessment on Stages of Employment Readiness (LASER) was developed to assess welfare recipients' employment readiness. The LASER consists of 14 items corresponding to Prochaska's stages of change model (Prochaska, DiClemente and Norcross, 1992). A sample of 149 welfare recipients from a work training program participated in the study. The Confirmatory Factor Analysis (CFA) supported the three factors structure corresponding to Prochaska's Pre-Contemplation, Contemplation, and Action stages. A cluster analysis classified the sample into three groups according to their LASER scores. A six months follow-up on employment outcomes showed that those who were in Pre-contemplation stage had the poorest employment outcome (25%), those who were in the Action stage had the best outcome (56%) and those in the Contemplation stage were in between (38%). Implications for work rehabilitation and treatment matching were discussed.