Using Gas Chromatography with Ion Mobility Spectrometry to Resolve Explosive Compounds in the Presence of Interferents*

Abstract: Ion mobility spectrometry (IMS) is a valued field detection technology because of its speed and high sensitivity, but IMS cannot easily resolve analytes of interest within mixtures. Coupling gas chromatography (GC) to IMS adds a separation capability to resolve complex matrices. A GC‐IONSCAN^® operated in IMS and GC/IMS modes was evaluated with combinations of five explosives and four interferents. In 100 explosive/interferent combinations, IMS yielded 21 false positives while GC/IMS substantially reduced the occurrence of false positives to one. In addition, the results indicate that through redesign or modification of the preconcentrator there would be significant advantages to using GC/IMS, such as enhancement of the linear dynamic range (LDR) in some situations. By balancing sensitivity with LDR, GC/IMS could prove to be a very advantageous tool when addressing real world complex mixture situations.     

Understanding how sexual offenders compare across psychiatric and correctional settings: examination of Canadian mentally ill sexual offenders

Abstract

Much of what is known about sexual offenders is based on correctional samples and then applied across settings based on the assumption that this group is homogeneous. In this study, 149 files were compared, including 108 cases from the forensic mental health system (FMH) and 41 cases from the correctional system (COR). Although many similarities were observed between the FMH and COR groups, the results also revealed important differences. The FMH group was characterised by more frequent hospitalisations, higher rates of major mental illness and single status. The COR group was characterised by a history of physical and sexual abuse, family history of addictions, more intrusive sexual offences and higher rates of offending. These results highlight different profiles for sexual offenders in forensic mental health and correctional settings and challenge us to consider the implications for assessment, treatment and risk management of this unique group of sexual offenders.     

Book Reviews

Jarol B. Manheim, All of the People all the Time: Strategic Communication and American Politics (New York: M.E. Sharpe, Inc., 1991), 255 pp. $25.00.

Harry C. Mansfield, Jr., America's Constitutional Soul (Baltimore, MD: Johns Hopkins Press, 1991), pp. 236.

Donald L. Horowitz, A Democratic South Africa? (Berkeley, CA: University of California Press, 1991), 293 pp. $24.95.     

Regional prosperities compared: Massachusetts and Baden-Württemberg in the 1980s

This article compares the relationship between economic development and public policy in two of the most prosperous regions of the 1980s: Massachusetts in the United States and Baden-Württemberg in West Germany. Beginning with a critique of the theory of the product life-cycle, the article examines the rise and fall of traditional industries in Massachusetts and their survival in Baden-Württemberg. It then goes on to consider the rise–but also the vulnerability–of the high-tech and financial firms in Massachusetts, as well as the more robust, though almost invisible growth of these sectors in Baden-Württemberg. The burden of the argument is that there are, strictly speaking, no ‘mature’ industries and public policies aimed at stimulating innovation are most successful when the latter is integrated into the local industrial structure as a whole rather than isolated into a distinct high-tech sector.     

Simulating commercial policy in a small,open dual economy with urban unemployment: A general equilibrium approach

A two‐sector numerical general equilibrium model calibrated on Kenyan data is used to consider second‐best tariff policy in an economy with a distorted market for urban‐industrial labour and urban unemployment. The results illustrate the sensitivity of second‐best policy to the way the administered urban wage is determined (whether it is fixed primarily in terms of food or the manufactured good), and to the degree of inter‐sectoral mobility of capital. Efficiency gains from moving to a second‐best policy are shown to be small in comparison with the gains from eliminating the wage distortion in the first place.     

Measuring the quality of election administration

How do we distinguish between a ‘genuine’, ‘free and fair’, or ‘legitimate’ election and an election that is something less? In this article, we offer an answer to this vexing question: the Election Administration Systems Index (EASI). EASI is a practical, transparent, and sustainable tool for measuring the quality of elections in the developing world. The following pages describe the current limitations in measuring election quality, detail the EASI approach, and provide a comparative analysis of the results of its pilot implementation. EASI scores are drawn from a survey of experts on elections in the target country following a recent nationwide election. The analytical framework is comprised of three electoral dimensions: participation, competition, and integrity of the process. We also divide these dimensions temporally according to the electoral cycle: either pre-election, during the election, or post-election. The final product is a set of six primary scores displayed across dimension and time. By aggregating the survey data in this fashion, we provide for a nuanced assessment of an election by each dimension and across the cycle. As our pilot results demonstrate, EASI is a diagnostic tool for identifying electoral strengths and weaknesses and serves well for comparative assessments.     

The English common law criminal defence and excuse of necessity: a critical comparison of the customary law and commonplace

A defendant turned off an oil pipeline argued and used the common law defence of necessity. The Court permitted the accused to argue that this action was necessary to decelerate calamitous climate change. The objective is to compare critically the development and use of the defence and excuse of necessity. The question is whether Lord Coleridge had a prejudging objective, in R v. Dudley and Stephens, and if so, what was it likely to have been. Necessity, as an excuse, is a categorical imperative because it is of the same structure as violating a law to save the state.     

Correlation between saw blade width and kerf width

Most studies of saw marks have focused on morphological characteristics and their utility in identifying saws suspected to have been utilized in cases of criminal dismemberment. The present study examined the extent to which metric analysis may be used to correlate saw blade measurements with minimum kerf widths (MKWs). A sample of 56 partially defleshed white‐tailed deer (Odocoileus virginianus) long bones was utilized as proxy for human remains. The long bones were cut using a variety of commercially available saws, including 11 manual‐powered and 5 mechanical‐powered saws. A total of 496 false start kerfs (FSKs) were created. Two experiments were performed, with the first test examining the MKWs of FSKs produced on specimens that were restrained using a bench vise, while the second test analyzed the MKWs of FSKs produced on minimally restrained specimens. Statistical analysis using Hierarchical Linear Modeling (HLM) indicated a positive relationship between saw blade width (mm) and MKW, with blade width (p < 0.001) and the overall difference between the mechanical‐ and manual‐powered saws (p = 0.029) tested, reaching statistical significance. A comparison of MKWs produced using manual‐powered saws on restrained and minimally restrained bones suggests that restraint condition (p = 0.009) has a statistically significant effect. In comparisons of MKWs to blade widths, the average ratio for mechanical‐powered saws is 18.7% greater than the average ratio for manual‐powered saws. While the mode of the ratios was 1.42, thus supporting the general rule that MKW does not exceed 1.5 times blade width, multiple individual ratios did surpass 1.5.