The Skew-Normal Distribution on the Simplex

Density functions on the simplex defined with respect to the Lebesgue measure can change from unimodality to multimodality with perturbation. This phenomenon is induced by the incompatibility of the Aitchison geometry and the Lebesgue measure. A Lebesgue-type measure, compatible with the algebraic geometric structure of the simplex, is used here to define the skew-normal density on the simplex as the Radon-Nykodym derivative with respect to it. Similarities and differences between the densities obtained using the different measures are analyzed.     

A Note on the Prior Distributions of Weibull Parameters for the Reliability Function

In Bayesian Inference it is often desirable to have a posterior density reflecting mainly the information from sample data. To achieve this purpose it is important to employ prior densities which add little information to the sample. We have in the literature many such prior densities, for example, Jeffreys (1967 Jeffreys , H. ( 1967 ). Theory of Probability , 3rd rev. ed. . London : Oxford University Press . [Google Scholar]), Lindley (1956 Lindley , D. V. ( 1956 ). On a measure of the information provided by an experiment . Ann. Mathemat. Statist. 27 : 986 – 1005 .[Crossref] , [Google Scholar]); (1961 Lindley , D. V. ( 1961 ). The use of prior probability distributions in statistical inference and decisions . In: Neyman , J. , ed. Proceedings of the Fourth Berkeley Symposium on Mathematical Statistics and Probability . Vol. 1. Berkeley : University of California Press , pp. 453 – 468 . [Google Scholar]), Hartigan (1964 Hartigan , J. ( 1964 ). Invariant priors distributions . Ann. Mathemat. Statist. 35 : 836 – 845 .[Crossref] , [Google Scholar]), Bernardo (1979 Bernardo , J. M. ( 1979 ). Reference posterior distributions for Bayesian inference . J. Roy. Statist. Soc. 41 ( 2 ): 113 – 147 . [Google Scholar]), Zellner (1984 Zellner , A. ( 1984 ). Maximal Data Information Prior Distributions, Basic Issues in Econometrics . Chicago : University of Chicago Press . [Google Scholar]), Tibshirani (1989 Tibshirani , R. ( 1989 ). Noninformative priors for one parameters of many . Biometrika 76 : 604 – 608 .[Crossref], [Web of Science ®] , [Google Scholar]), etc. In the present article, we compare the posterior densities of the reliability function by using Jeffreys, the maximal data information (Zellner, 1984 Zellner , A. ( 1984 ). Maximal Data Information Prior Distributions, Basic Issues in Econometrics . Chicago : University of Chicago Press . [Google Scholar]), Tibshirani's, and reference priors for the reliability function R(t) in a Weibull distribution.     

Multivariate Three-Parameter Log-Elliptical Distributions

The three-parameter log-elliptical distribution class is developed for the general situation in which the hypothesis of independence for the elements in a sample is not assumed. The parameter estimators are theoretically showed to be invariant under all distributions in the class by considering only a change in the constant of the scale parameter estimator. An estimation procedure based on the three-parameter lognormal distribution is proposed for the parameter estimation problem in any three-parameter log-elliptical distribution. Two classical lognormal data sets are analyzed without assuming independence in the sample in order to illustrate the proposed estimation procedure.     

Transformational leadership and ambidexterity in the context of an acquisition

This study explores the role of transformational leadership and the values incorporated in a learning culture in promoting ambidexterity (the ability to explore new capabilities while exploiting existing ones) in teams involved in acquisition integrations. Data from a field study of an acquisition integration (N = 71 work teams) support hypotheses arguing that transformational leadership behaviors and the development of a learning culture, characterized by psychological safety, openness to diverse opinions, and participation in decision making, promote ambidexterity at the team level. We also found support for the association between transformational leadership and learning cultures.     

On the Solution Approach for Bayesian Modeling of Initiating Event Frequencies and Failure Rates

There is a need for plant-specific distributions of incidence and failure rates rather than distributions from pooled data which are based on the "common incidence rate" assumption. The so-called superpopulation model satisfies this need through a practically appealing approach that accounts for the variability over the population of plants. Unfortunately, the chosen order in which the integrals with respect to the individual plant rates λ_i, ( i = 0, 1…, m ) and the parameters a , β of the Γ-population distribution are solved seems to drive the solution close to the common incidence rate distribution. It is shown that the solution obtained from interchanging the order and solving the integrals with respect to the individual plant rates by Monte Carlo simulation very quickly provides the plant specific distribution. This differing solution behaviour may be due to the lack of uniform convergence over (α, β, λ_I, ( i = 1,…, m ))-space. Examples illustrate the difference that may be observed.     

A Capture–Recapture Approach to Estimation of Refugee Populations

The debate over immigration continues to be one of the most politically charged policy issues in the United States (US). Given the charged nature of this topic, it is vitally important to have reliable data on not only the number of US foreign nationals but also the characteristics of this extremely heterogeneous group – a population comprised not only of immigrants but also of refugees. There exist a small number of data sources for informing policy and practice at the national level. However, such data are often lacking for smaller geographical areas. This paper describes a recent effort to generate serviceable data on the immigrant and refugee population for a medium‐sized metropolitan area in the US. The objectives of this research were twofold. Our first goal was to provide local stakeholders with information to assist them with resettling and obtaining funding for immigrants and refugees. The second aim was to develop better techniques for tabulating diverse refugees and immigrants in a medium‐sized community. By comparing and contrasting three data sources – that is, refugee services, public schools and a local health plan – we are able to generate estimates of the local refugee and immigrant population. During the period from 2005 to 2007, we estimate the total number of immigrants and refugees in the community to be somewhere between 10,938 and 13,282. Although perhaps a bit on the high end due to methodological assumptions, these estimates seem plausible, based on previously cited figures for the region. While such estimates are valuable, a number of shortcomings related to the data prevent us from painting a more complete picture of these populations. We conclude this paper with a number of recommendations that will assist others in planning research designed to inform migration policy and practice in medium‐sized metropolitan areas.     

‘Civilising’ Deaf people in Tibet and Inner Mongolia: governing linguistic,ethnic and bodily difference in China

The People’s Republic of China is home to over 20 million d/Deaf and hard-of-hearing people, many among them belonging to ethnic minorities. Drawing on ethnographic fieldwork in two minority regions, the Tibet Autonomous Region and the Inner Mongolian Autonomous Region, this article comparatively discusses findings on sign language use, education and state welfare policies. The situation in these domains is analysed through the framework of the ‘civilising project’, coined by Harrell, and its impacts on the d/Deaf and hard-of-hearing among ethnic minorities are shown. For instance, through the promotion of Chinese and Chinese Sign Language over and above the use of local sign and written languages as well as through education and the medicalisation of disabilities.     

Disempowered by the media: causes and consequences of the lack of media voice of Roma communities

ABSTRACT

Roma communities have experienced widespread historical exclusion in most European countries. The media can be a powerful instrument of a group’s inclusion into the mental map of a society, or, on the contrary, it can contribute to the group’s exclusion and disempowerment. This article builds on a series of content and discursive analyses of the news media’s coverage of Hungarian Roma communities since 1993, interviews with stakeholders and focus group discussions in Roma communities. It scrutinises media reporting about Roma and argues that, in general, the scope and the agenda of Roma’s portrayal coincide with mainstream society’s stereotypes about the group. The article will additionally look at the media’s disempowering role from two perspectives: on the one hand, the extent to which Roma have access to influencing media content, and on the other hand, it will consider the role of minority communities in challenging stereotypical images.     

The entanglement of leader character and leader competence and its impact on performance

Whereas the micro- and macro-oriented leadership literatures have often studied leader competencies necessary for effective performance, the role of leader character in relation to competencies and performance has been to a large extent neglected. Our work seeks to shift the scholarly dialogue by introducing the concept of character-competence entanglement, which reflects the binding between character and competence over time. The highest degree of entanglement represents the deep and more persistent interconnection and mutually-reinforcing effect between highly-developed leader character and highly-developed leader competence, whereas in cases of low entanglement, character can be activated temporarily in a particular context to help strengthen the relationship between competence and performance. Our core proposition is that high character-competence entanglement will lead to extraordinary performance over time. In addition, we emphasize that relying on naturally-occurring learning opportunities and the processes of “learning-by-living” both outside and inside the organization will positively impact the development of character-competence entanglement.