Experimental results on data analysis algorithms for extracting and interpreting edge feature data for duct tape and textile physical fit examinations

A physical fit is an important observation that can result from the forensic analysis of trace evidence as it conveys a high degree of association between two items. However, physical fit examinations can be time-consuming, and potential bias from analysts may affect judgment. To overcome these shortcomings, a data analysis algorithm using mutual information and a decision tree has been developed to support practitioners in interpreting the evidence. We created these tools using data obtained from physical fit examinations of duct tape and textiles analyzed in previous studies, along with the reasoning behind the analysts' decisions. The relative feature importance is described by material type, enhancing the knowledge base in this field. Compared with the human analysis, the algorithms provided accuracies above 90%, with an improved rate of true positives for most duct tape subsets. Conversely, false positives were observed in high-quality scissor cut (HQ-HT-S) duct tape and textiles. As such, it is advised to use these algorithms in tandem with human analysis. Furthermore, the study evaluated the accuracy of physical fits when only partial sample lengths are available. The results of this investigation indicated that acceptable accuracies for correctly identifying true fits and non-fits occurred when at least 35% of a sample length was present. However, lower accuracies were observed for samples prone to stretching or distortion. Therefore, the models described here can provide a valuable supplementary tool but should not be the sole means of evaluating samples.     

A study of DNA transfers onto plastic packets placed in personal bags

The ability to detect low level DNA brings with it the uncertainty of whether the detected DNA is a result of transfer. To address this uncertainty, a simulation study was conducted in which a mock illicit drug packet was placed into the personal bags of individuals. When the average transit time of the packets was increased from around 2 h to more than 14 h, the percentage of the DNA profiles recovered from the packets which could be attributed to the individuals increased greatly from 5.3% to 48.6%. We found that drug packers who were poor shedders could not be included as contributors to the DNA profiles from the drug packets at all and there was a higher chance that individuals other than themselves could be included as contributors to the DNA profile recovered from drug packets. We also found that it was equally likely that the drug packers who had direct contact with the drug packets and bag owners who did not, could be included as contributors to the DNA profiles recovered from the packets. The results in this study highlight the importance of taking into consideration the transit time of drug packet, the shedder status of the alleged packer and the history of an item, when evaluating DNA evidence in the context of illicit drug activities.     

Portion size matters: Carrion ecology lessons for medicolegal death investigations—A study in Cape Town,South Africa

Forensic taphonomic studies are regionally specific and improve time since death estimates for medico-legal casework. Within forensic taphonomy and carrion ecology, vertebrate scavengers are under-researched with many studies conducted using multiple, unclothed carcasses. This is a forensically unrealistic experimental design choice with unknown impact. The effect of variation in carrion biomass on the decomposition ecosystem, particularly where vertebrate scavengers are concerned, requires clarification. To assess the effect of carrion biomass load on vertebrate scavenging and decomposition rate, seasonal baseline data for single, clothed ~60 kg porcine carcasses were compared to clothed multiple-carcass deployments, in a forensically relevant habitat of Cape Town, South Africa. Decomposition was tracked via weight loss and bloat progression and scavenging activity via motion-activated cameras. The single carcasses decayed more quickly, particularly during the cooler, wetter winter, strongly correlated with concentrated Cape gray mongoose (Galerella pulverulenta) scavenging activity. On average and across seasons, the single carcasses lost 68% of their mass by day 32 (567 accumulated degree days [ADD]), compared to 80 days (1477 ADD) for multi-carcass deployments. The single carcasses experienced substantially more scavenging activity, with longer visits by single and multiple mongooses, totaling 53 h on average compared to 20 h for the multi-carcass deployments. These differences in scavenging activity and decay rate demonstrate the impact of carrion biomass load on decomposition for forensic taphonomy research. These findings need corroboration. However, forensic realism requires consideration in taphonomic study design. Longitudinally examining many single carcasses may produce more forensically accurate, locally appropriate, and usable results.     

Researching counterterrorism: a critical perspective from the field in the light of allegations and findings of covert activities by undercover police officers

The article addresses some of the key issues that are raised for researchers engaging with counterterrorism police officers and initiatives, when undertaking research. A significant area to explore in this context is, in fact, the issue of relationships with counterterrorism police officers who may themselves directly have been covert police officers in the past and/or who may be continuing in their current, apparently more open, role (wittingly or otherwise) as agents of broader state strategies of exploiting trust for intelligence-gathering purposes. This article suggests that it is important for researchers to understand that working within the counterterrorism field involves degrees and shades of risk in the service of trust-building, sensitivity and the empowerment of communities, and that researchers themselves can (wittingly and unwittingly) be part of wider strategies instigated by security-minded individuals or groups of counterterrorism police officers. Reflecting upon the research that we have undertaken individually and collectively over the last number of years, in the light of the most recent spate of allegations about counterterrorism police officers infiltrating activist and political protest groups, having sexual relationships, and indeed, on occasion, children, with women whilst undercover and of potentially working to entrap vulnerable individuals into planning terrorist acts, this article raises questions around trust, credibility, legitimacy, the prevalence and near unavoidability of dysfunctional agendas and the implications of all of the above for community-based approaches to counterterrorism.     

Energy Crime,Harm, and Problematic State Response in Colorado: A Case of the Fox Guarding the Hen House?

Crime related to energy extraction is an emerging area of interest among green and critical criminologists. This paper contributes to that developing work by examining the political economy of harm and crime associated with the oil and natural gas industry in rural Colorado. Specifically, we examine problematic state regulatory response to citizens’ complaints regarding a range of harms caused by private industry (e.g., water pollution, adverse human health consequences, and domestic livestock death). In this paper, we draw on content analysis of formal complaints filed by citizens to the state, ethnographic work, and intensive interviews with citizens seeking relief from problematic or abusive industry practices. Our analysis illuminates how the state documents these practices, how citizens experience them, and how the state dilutes and deflects the externalities of energy extraction to produce additional harm.     

Comparing the Recognition Memory Test and the Word Choice Test in a Mixed Clinical Sample: Are They Equivalent?

The Recognition Memory Test (RMT) was compared to the Word Choice Test (WCT) within the same fixed neuropsychological battery administered to a mixed clinical sample of 237 adults to empirically evaluate the psychometric equivalence of these two instruments. On average, there was a 3-point difference in raw scores between the two instruments (M _RMT?=?44.3, SD _RMT?=?6.8; M _WCT?=?47.1, SD _WCT?=?4.6; p?d?=?.48). The probability density functions differ substantially at the two ends of the scale but are similarly ≤42. Cross-validation analyses suggest that the RMT cutoff of ≤42 is functionally equivalent to a WCT score of ≤45.     

Do bone elasticity and postmortem interval affect forensic fractographic analyses?

Forensic fractographic features of bone reliably establish crack propagation in perimortem injuries. We investigated if similar fracture surface features characterize postmortem fractures. Experimentally induced peri- and postmortem fractures were used to assess if fractographic features vary as bone elasticity decreases during the postmortem interval (PMI). Thirty-seven unembalmed, defleshed human femoral shafts from males and females aged 33–81 years were fractured at varying PMIs with a drop test frame using a three-point bending setup and recorded with a high-speed camera. Vital statistics, cause of death, PMI length, temperature, humidity, collagen percentage, water loss, fracture energy, and fractography scores were recorded for each sample. Results showed that fractographic features associated with perimortem fractures were expressed in PMIs up to 40,600 accumulated degree hours (ADH), or 60 warm weather days. Hackle was the most consistently expressed feature, occurring in all fractures regardless of ADH. The most variable characteristics were wake features (78.4%) and arrest ridges (70.3%). Collagen percentage did not correlate strongly with ADH (r = −0.04, p = 0.81); however, there was a strong significant correlation between ADH and water loss (r = 0.74, p < 0.001). Multinomial logistic regression showed no association between fractographic feature expression and ADH or collagen percentage. In conclusion, forensic fractographic features reliably determine initiation and directionality of crack propagation in experimentally induced PMIs up to 40,600 ADH, demonstrating the utility of this method into the recent postmortem interval. This expression of reliable fractographic features throughout the early PMI intimates these characteristics may not be useful standalone features for discerning peri- versus postmortem fractures.     

From issues to goals: a novel conceptualisation,measurement and research design for comprehensive analysis of electoral competition

Abstract

The analysis of issue politics has long suffered from a fragmentation between valence and positional conceptualisations, preventing the effective development of a general model of issue-based party competition. Building on an overview of the evolution of party competition in the Western world in recent decades, this article offers a theoretical development that builds on ‘issue yield’ theory to provide a conceptualisation of political goals that generalises across positional and valence issues. This in turn allows a common measurement strategy, offering the possibility to comparatively assess various characteristics (including the electoral potential) of both positional and valence issues. Finally, it describes the specific research design derived from this framework and its implementation in comparative perspective in six West European countries during 2017–2018.     

Should algorithms be regulated by government?

There has been, and continues to be, an explosion in the use of algorithms across the economy and society. There are growing concerns about how algorithms are being used and whether they are accountable. This article reviews the literature on the issue of algorithms in several key areas, such as fairness, accountability, and transparency. The article examines arguments on why algorithms should be regulated, and it explores the available literature to identify how a potential Canadian regulatory framework may be developed.     

The mourning process and “living with the dead”: Two case reports and a review of the literature

The discovery of mummified bodies in domestic settings is not unusual in the medico‐legal context. It is often a marker of social isolation, even in our urban modern society, and usually occurs among elderly people living alone or in precarious conditions. However, bereaved subjects can sometimes be found managing their grief by deliberately keeping the corpses of their loved ones at home. Investigation of these atypical cases can be challenging and often requires a multidisciplinary effort by different forensic specialists. We report two cases of people who lived for several months with the mummified remains of a relative. In both cases, the judge ordered a forensic psychiatry assessment of the survivors’ competency and the reasons for this peculiar behavior, which is regarded as abnormal in our society. Case 1 describes a shared psychosis, which developed out of a condition of extreme seclusion of the entire family. Case 2 shows that even a mild personality disorder on which a series of traumatic events operates can trigger psychotic decompensation, causing extreme denial of the reality of death. The analysis of these cases contributes to our knowledge of the scantly studied phenomenon of “Living with the Dead” and raises questions about the psychopathology behind it. It is useful to identify subjects who are more prone to developing this “deviant” behavior, in order to distinguish people with mental illness from those who merely want to profit from the death of a loved one.