Estimating Lorenz Curves Using a Dirichlet Distribution.

The Lorenz curve relates the cumulative proportion of income to the cumulative proportion of population. When a particular functional form of the Lorenz curve is specified it is typically estimated by linear or nonlinear least squares, estimation techniques that have good properties when the error terms are independently and normally distributed. Observations on cumulative proportions are clearly neither independent nor normally distributed. This paper proposes and applies a new methodology that recognises the cumulative proportional nature of the Lorenz curve data by assuming that the income proportions are distributed as a Dirichlet distribution. Five Lorenz-curve specifications are used to demonstrate the technique. Maximum likelihood estimates under the Dirichlet distribution assumption provide better-fitting Lorenz curves than nonlinear least squares and another estimation technique that has appeared in the literature.Gini coefficient; maximum likelihood estimation

On Calculation of the Extended Gini Coefficient.

The conventional formula for estimating the extended Gini coefficient is a covariance formula provided by Lerman and Yitzhaki (1989). We suggest an alternative estimator obtained by approximating the Lorenz curve by a series of linear segments. In a Monte Carlo experiment designed to assess the relative bias and efficiency of the two estimators, we find that, when using grouped data with 20 or less groups, our new estimator has less bias and lower mean squared error than the covariance estimator. When individual observations are used, or the number of groups is 30 or more, there is little or no difference in the performance of the two estimators.ESTIMATORS ; COEFFICIENTS ; EFFICIENCY

The Middlesex University 'Africa Group' Showcase

The aim of the Africa Group is to explore commonalities of interests in Africa across the university and encourage inter-disciplinary discourse and activity in order to further enhance projects being undertaken, and to develop new joint research-focused or research-informed projects. It will focus on what can be learned from Africa, rather than what Africa can learn from us - knowledge sharing rather than knowledge transf

Fuel from waste unConference: welcome and introduction

Welcome, philosophy and approach to activity for the 2011 Fuel from Waste unConference

An electrolytic process for ultra fine beryllium

Studies were made on the electrolysis of a molten BeCl2-NaCl bath using a mercury cathode and beryllium anode. A quasi-amalgam was obtained. The beryllium was consolidated by direct hot pressing of the amalgam at temperatures in the range of 800 C and using pressures of 5,000, 10,000 and 20,000 psi. The work confirms the ability to produce ultrafine beryllium particles by electrolysis

Mindfulness in mental health: a critical reflection

Mindfulness derives from Buddhist practice and is fundamentally concerned with the development of present moment awareness. It is arguably one of the fastest growing areas of mental health research with the last decade witnessing a tenfold increase in the number of published scientific papers concerning the applications of mindfulness in mental health contexts. Given the demonstrable growth of interest into the clinical utility of mindfulness, this paper provides a: (i) timely and evidence-based appraisal of current trends and issues in psychopathology-related mindfulness research, and (ii) discussion of whether the empirical evidence for mindfulness-based interventions actually merits their growing popularity and utilization amongst mental health stakeholders. It is concluded that mindfulness-based interventions have the potential to play an important role in psychiatric treatment settings as well as in applied psychological settings more generally. However, due to the rapidity at which mindfulness has been taken out of its traditional Buddhist setting, and what is possibly evidence of media and/or scientific hype concerning the effectiveness of mindfulness, it is recommended that future research seeks to: (i) consolidate and replicate research findings, (ii) assess the maintenance of outcomes over longer time periods, (iii) investigate potential adverse effects, and (iv) fully control for potential performance bias in mindfulness-based intervention studies. It is further recommended that future research seeks to investigate the Buddhist position that sustainable improvements to mental and spiritual health typically require consistent daily mindfulness practice over a period of many years (i.e., they do not arise after attending eight two-hour classes with some self-practice in between)