Homicide by unusual‐edged weapons: Forensic considerations of two cases

Homicide by stab wound is common worldwide. However, the use of unusual edged weapons is rarely reported in the forensic literature. Here, we report two cases of homicide involving a Japanese sword, or katana, and a sickle. Both of these weapons can create either stab or incised wounds with some particularities. In our cases, characteristics of the external wounds, internal injuries, and the depth of penetration raised the possibility of an unusual weapon. Meticulous forensic examination of these injuries (morphological characteristics, depth of penetration, trajectories, and cut marks in the bone) may allow the forensic expert to determine the type of weapon used.     

Identification of furosemide in hair in a post‐mortem case by UHPLC‐MS/MS with guidance on interpretation

Testing for drugs in hair raises several difficulties. Among them is the interpretation of the final concentration(s). In a post‐mortem case, analyses revealed the presence of furosemide (12 ng/mL) in femoral blood, although it was not part of the victim's treatment. The prosecutor requested our laboratory to undertake an additional analysis in hair to obtain information about the use of furosemide. A specific method was therefore developed and validated to identify and quantify furosemide in hair by UHPLC‐MS/MS. After decontamination of 30 mg of hair, incubation in acidic condition, extraction with ethyl acetate, the samples were analyzed by UHPLC‐MS/MS. Furosemide was found in the victim's hair at 225 pg/mg. However, it was not possible to interpret this concentration due to the absence of data in the literature. Therefore, the authors performed a controlled study in two parts. In order to establish the basis of interpretation, several volunteers were tested (four after a single 20 mg administration and twenty‐four under daily treatment). The first part indicated that a single dose is not detectable in hair using our method. The second part demonstrated concentrations ranging from 5 to 1110 pg/mg with no correlation between dosage and hair concentrations. The decedent's hair result was interpreted as repeated exposures. In the case of furosemide analysis, hair can provide information about its presence but cannot give information about dosage or frequency of use.     

Characterization and differentiation of aluminum powders used in improvised explosive devices – Part 1: Proof of concept of the utility of particle micromorphometry

Aluminum (Al) powders are commonly used in improvised explosive devices as metallic fuels, a component of explosive mixtures. These powders can be obtained readily from industrial‐scale and consumer products, and produced using unsophisticated “kitchen chemistry” techniques. This research demonstrates the potential of automated particle micromorphometry for comparisons between known source and questioned Al powders recovered from IEDs, as well as for insight into the method of Al powder manufacture. Al powder samples were obtained from legitimate manufacturers, and 56 samples were produced “in‐house” from Al‐containing spray paints and ball‐milled Al foils. Transmitted light microscope images of Al powder particles were acquired using an automated stage with automated z‐focus; 17 size and shape parameters were measured for all particles. Approximately 37,000–2,500,000 particles/sample were analyzed using an open‐source statistical package with customized code. Dimensionality reduction was required for processing the large datasets: eight of the 17 measured variables were selected based on inspection of the correlation matrix. Data from four subsamples from each of the 56 samples produced using “in‐house” methods were analyzed using ANOVA to assess the within‐ and between‐sample variation. High within‐sample variation was noted; however, ANOVA and post‐hoc Tukey's honestly significant difference (HSD) tests demonstrated that the between‐sample variation was substantially larger than the within‐sample variation. Each sample could be differentiated from all other samples in the test set. Future experiments will focus on ways to reduce the within‐sample variation, and additional statistical and microanalytical methods to classify sources and confidently constrain the method of Al powder manufacture.     

Firearm examination: Examiner judgments and computer‐based comparisons

Forensic firearm examination provides the court of law with information about the source of fired cartridge cases. We assessed the validity of source decisions of a computer‐based method and of 73 firearm examiners who compared breechface and firing pin impressions of 48 comparison sets. We also compared the computer‐based method's comparison scores with the examiners' degree‐of‐support judgments and assessed the validity of the latter. The true‐positive rate (sensitivity) and true‐negative rate (specificity) of the computer‐based method (for the comparison of both the breechface and firing pin impressions) were 94.4% and at least 91.7%, respectively. For the examiners, the true‐positive rate was at least 95.3% and the true‐negative rate was at least 86.2%. The validity of the source decisions improved when the evaluations of breechface and firing pin impressions were combined and for the examiners also when the perceived difficulty of the comparison decreased. The examiners were reluctant to provide source decisions for "difficult" comparisons even though their source decisions were mostly correct. The correlation between the computer‐based method's comparison scores and the examiners' degree‐of‐support judgments was low for the same‐source comparisons to negligible for the different‐source comparisons. Combining the outcomes of computer‐based methods with the judgments of examiners could increase the validity of firearm examinations. The examiners' numerical degree‐of‐support judgments for their source decisions were not well‐calibrated and showed clear signs of overconfidence. We suggest studying the merits of performance feedback to calibrate these judgments.     

Bruise dating using deep learning

The bruise dating can have important medicolegal implications in family violence and violence against women cases. However, studies show that the medical specialist has 50% accuracy in classifying a bruise by age, mainly due to the variability of the images and the color of the bruise. This research proposes a model, based on deep convolutional neural networks, for bruise dating using only images, by age ranges, ranging from 0–2 days to 17–30 days, and images of healthy skin. A 2140 experimental bruise photograph dataset was constructed, for which a data capture protocol and a preprocessing procedure are proposed. Similarly, 20 classification models were trained with the Inception V3, Resnet50, MobileNet, and MnasNet architectures, where combinations of learning transfer, cross‐validation, and data augmentation were used. Numerical experiments show that classification models based on MnasNet have better results, reaching 97.00% precision and sensitivity, and 99.50% specificity, exceeding 40% precision reported in the literature. Also, it was observed that the precision of the model decreases with the age of the bruise.     

Evaluation, Policy Learning and Evidence-Based Policy Making

The increasing emphasis on the need for evidence-based policy indicates the continuing influence of the 'modernist' faith in progress informed by reason. Although the rationalist assumptions of evidence-based policy making have been subject to severe challenge from constructivist and post-modernist perspectives, it is argued that the attempt to ground policy making in more reliable knowledge of 'what works' retains its relevance and importance. Indeed, its importance is enhanced by the need for effective governance of complex social systems and it is argued that 'reflexive social learning' informed by policy and programme evaluation constitutes an increasingly important basis for 'interactive governance'. The expanded use of piloting of new policies and programmes by the current UK Government is considered to provide limited scope for evaluation to derive reliable evidence of whether policies work. There is a need for greater clarity about the role of evaluation in situations where piloting essentially constitutes 'prototyping'. More emphasis should be placed on developing a sound evidence base for policy through long-term impact evaluations of policies and programmes. It is argued from a realist position that such evaluation should be theory-based and focused on explaining and understanding how policies achieve their effects using 'multi-method' approaches.     

The institutionalization of identity: Micro adaptation, macro effects, and collective consequences

Constructivist approaches to the emergence and stability of collective identities are now widely accepted. But few of the assumptions of constructivist theory regarding repertoires of identities and their mutability in response to changing circumstances have been examined or even articulated. The article shows how different conditions of a fluid and changing environment affect the stabilization or institutionalization of an identity as dominant within a polity. We used the Agent-Based Identity-Repertoire (ABIR) model as a simulation tool and confined our attention to relatively simple identity situations. Strong evidence was found for the emergence of identity institutionalization, the existence of a “crystallization” threshold, the effectiveness of divide-and-rule strategies for the maintenance of an identity as dominant, the efficacy of a network of organic intellectuals, and hegemonic levels of institutionalization. Thresholds leading to hegemony were not observed. Preliminary results from experiments examining more complex identity situations have been corroborative. Ian S. Lustick is professor of political science at the University of Pennsylvania. He is the author ofUnsettled States, Disputed Lands: Britain and Ireland, France and Algeria, Israel and the West Bank/Gaza. His current research involves development and expansion of agent-based modeling techniques for the study of identity politics, learning, globalization, and terrorism. Dan Miodownik is a doctoral candidate in the University of Pennsylvania Department of Political Science. His dissertation integrates statistical, historical, and agent-based modeling techniques to explore the relationship between changing communications technologies and competition among identity projects in Europe.     

Contingent and Non-Contingent Working in Local Government: Contrasting Psychological Contracts

Given that the contingent worker is likely to be a familiar presence in the public service workplace of the future, this paper explores the consequences of contingent work arrangements on the attitudes and behaviour of employees using the psychological contract as a framework for analysis. Drawing upon survey evidence from a sample of permanent, fixed term and temporary staff employed in a British local authority, our results suggest that contract status plays an important role in how individuals view the exchange relationship with their employer and how they respond to the inducements received from that relationship. Specifically, contingent employees are less committed to the organization and engage in organizational citizenship behaviour (OCB) to a lesser degree than their permanent counterparts. However, contrary to our hypothesis, the relationship between the inducements provided by the employer and OCB is stronger for contingent employees. Such findings have implications for the treatment of contingent and non-contingent employees in the public services.