Compositional Data Analysis in Forensic Geoscience

Statistics are regularly used to make some form of comparison between trace evidence or deploy the exclusionary principle (Morgan and Bull, 2007) in forensic investigations. Trace evidence are routinely the results of particle size, chemical or modal analyses and as such constitute compositional data. The issue is that compositional data including percentages, parts per million etc. only carry relative information. This may be problematic where a comparison of percentages and other constraint/closed data is deemed a statistically valid and appropriate way to present trace evidence in a court of law. Notwithstanding an awareness of the existence of the constant sum problem since the seminal works of Pearson (1896) and Chayes (1960) and the introduction of the application of log-ratio techniques (Aitchison, 1986; Pawlowsky-Glahn and Egozcue, 2001; Pawlowsky-Glahn and Buccianti, 2011; Tolosana-Delgado and van den Boogaart, 2013) the problem that a constant sum destroys the potential independence of variances and covariances required for correlation regression analysis and empirical multivariate methods (principal component analysis, cluster analysis, discriminant analysis, canonical correlation) is all too often not acknowledged in the statistical treatment of trace evidence. Yet the need for a robust treatment of forensic trace evidence analyses is obvious. This research examines the issues and potential pitfalls for forensic investigators if the constant sum constraint is ignored in the analysis and presentation of forensic trace evidence. Forensic case studies involving particle size and mineral analyses as trace evidence are used to demonstrate the use of a compositional data approach using a centred log-ratio (clr) transformation and multivariate statistical analyses.

Similarity or Variation? Employee Representation and Consultation Approaches Amongst Liberal Market Economy Multinationals

This paper engages with the varieties of capitalism literature to investigate the employee representation and consultation approaches of liberal market economy multinational companies (MNCs), specifically Australian, British and US MNCs operating in Australia. While the literature would suggest commonality amongst these MNCs, the paper considers whether the evidence points to similarity or variation amongst liberal market headquartered MNCs. The findings contribute to filling a recognized empirical gap on MNC employment relations practice in Australia and to a better understanding of within category varieties of capitalism similarity and variation. Drawing on survey data from MNCs operating in Australia, the results demonstrated that UK-owned MNCs were the least likely to report collective structures of employee representation. Moreover, it was found that Australian MNCs were the most likely to engage in collective forms of employee representation and made less use of direct consultative mechanisms relative to their British and US counterparts. In spite of the concerted individualization of the employment relations domain over previous decades, Australian MNCs appear to have upheld more long-standing national institutional arrangements with respect to engaging with employees on a collective basis. This varies from British and US MNC approaches which denotes that our results display within category deviation in the variety of capitalism liberal market economy typology. Just as Hall and Soskice described their seminal work on liberal market economy (LME) and coordinated market economy (CME) categories as a “work-in-progress” (2001: 2), we too suggest that Australia’s evolution in the LME category, and more specifically its industrial relations system development, and the consequences for employment relations practices of its domestic MNCs, may be a work-in-progress.

Retinopathy of prematurity: Causes, prevention and treatment

Advances in neonatal intensive care have improved survival rates in extremely premature an infant, which has led to an increase of Retinopathy of Prematurity (ROP) in the developed world. Left untreated, infants are at risk of developing strabismus, myopia, vitreous haemorrhage, vitreo-retinal fibrosis, retinal detachment, secondary angle closure glaucoma and ultimately complete loss of vision. The improvements in the understanding and treatment of ROP have been supported by seminal research, and its complexity is still being explored. However the importance of early screening and treatment is essential in the prevention and treatment of this disease. The following paper will examine the causes and treatments of ROP, as well as implications for future neonatal practice.