From research integrity to research relevance to advance forensic science

Research is essential for any field to move forward. It allows us to expand our body of knowledge and enables any discipline to advance its application and meet its overall purpose. This is of course also essential for forensic science, a fundamentally research-based discipline, to develop and validate detection or examination methods and gather data and establish frameworks to understand forensic traces and their value to relevant stakeholders, such as law enforcement and the courts.     

Forensic applications of infrared chemical imaging: multi-layered paint chips

This paper examines the potential of infrared chemical (hyperspectral) imaging as a technique for the forensic analysis of automotive paint chips in particular, and multicomponent (e.g., layered) samples in general. Improved sample preparation procedures for the infrared analysis of paint chips are detailed, with the recommendation that where mounting resins are chemically incompatible with the sample, it is better to mount and section the sample in a soft wax from which the sections can be removed and pressed into a KBr disk for transmission analysis. Infrared chemical images of multilayered paint chips have been successfully obtained, with the chief advantage over conventional infrared analysis being that thousands of infrared spectra are collected in a few minutes across the whole sample, at a spatial resolution of around 5 microm. As with conventional infrared spectroscopy, chemical species can be identified from their spectra, but the wealth of information available can be also extracted in a number of different ways that make multicomponent spectral (and hence chemical) comparisons between two samples easy to visualize and understand. In one approach, the infrared chemical images of two paint chips being compared side-by-side can be viewed as a "movie," in which each frame is an intensity map of the two samples at a given wavenumber (frequency) value. In another approach, the spectra (pixels) in the image files are classified into chemically similar groups, resulting in a "cluster" image that makes it possible to simultaneously compare all of the layers in two paint chips. These methods are applicable to other multicomponent samples, and also to other chemical imaging techniques.     

“Here we give advice for free”: the functioning of plant clinics in Rwanda

Although plant clinics are considered an important mechanism in the service delivery to farmers, not much is known about their functioning in the daily reality of plant doctors and farmer-clients. This article reports on an exploratory study describing the functioning of eight plant clinics in Rwanda. Personal and organisational commitment, publicity, and proactive communication with farmers and local leaders are key factors explaining higher attendance of some clinics. Farmer attendance is under-reported by 40–50%. Data management needs improvement to make clinic records reliable tools for decision-makers. This type of assessment can help improve operations and realise the plant clinics’ potential.     

Deterrence and delinquency: An analysis of individual data

Is commission of crime deterred by fear of arrest? Individual self-reported data on the commission of three crimes are analyzed in relation to perceived probabilities of arrest for more than 3000 French-speaking teenagers of the Montreal school population in 1974. The crimes are shoplifting, drug use, and stealing an item worth more than $50.00. In addition to the effect of the individuals' perceptions of the probability of arrest for the three crimes, age, sex, and previous arrest record are also taken into account. The data are all categorical. A multivariate log-linear probability model is estimated in order to test hypotheses concerning the direction and magnitude of bivariate associations among the variables. We conclude that there is clear evidence of a negative association between the subjective probability of arrest for each crime and the frequency of commission of that crime. We also find some negative cross-effects of the perceptions of the probability of arrest for one type of crime on the commission of another, holding constant the direct effects.     

The demand for military expenditures: An international comparison

Earlier studies have explained inter-country variations in the share of GNP devoted to military expenditures by international spillovers and by differences in the threat of attack related to relative incomes. In this paper, we use the theory of public choice to explain these differences. We attempt to measure the importance of both international spillovers and relative incomes, along with two other factors: the tax-price elasticity of demand and economies of scale in the consumption of security. We find that international spillovers are significant and positive, that the income elasticity of demand is greater than unity, that the tax-price elasticity of demand explains part of observed inter-country differences, and that there are considerable economies of scale in the consumption of military spending. Finally, between 1960 and 1975, there was apparently a substantial increase in the value which each country derived from a dollar of military spending by its allies. This phenomenon, which seems related to the increased importance of deterrent weapons, has tended to induce individual alliance members to reduce the share of their national income devoted to defense.     

Mental disorders and cognitive impairment in ageing offenders

The aim of our study was to identify psychiatric and cognitive disorders among older prison inmates and to investigate whether there is an association between mental disorders and cognitive impairment. 138 men aged 50 and over were recruited in seven French prisons (Group 1) and 138 men aged 50 and over were recruited from the general public (Group 2). Participants were assessed using the Mini International Neuropsychiatric Interview, the Mini Mental State Examination, and the Frontal Assessment Battery. The results reveal very significant differences in the incidence of mental disorders and in cognitive performance between the two groups. However, there does not appear to be a significant link between mental disorders and cognitive performance. We discuss the risk factors for mental disorders and cognitive impairment. We raise particularly the issue of depression, which is the most common pathology in this population and which is generally associated with the risk of suicide.     

Gamma Irradiation as a Biological Decontaminant and Its Effect on Common Fingermark Detection Techniques and DNA Profiling

Abstract:  The use of disease-causing organisms and their toxins against the civilian population has defined bioterrorism and opened forensic science up to the challenges of processing contaminated evidence. This study sought to determine the use of gamma irradiation as an effective biological decontaminant and its effect on the recovery of latent fingermarks from both porous and nonporous items. Test items were contaminated with viable spores marked with latent prints and then decontaminated using a cobalt 60 gamma irradiator. Fingermark detection was the focus with standard methods including 1,2-indanedione, ninhydrin, diazafluoren-9-one, and physical developer used during this study. DNA recovery using 20% Chelex extraction and quantitative real-time polymerase chain reaction was also explored. Gamma irradiation proved effective as a bacterial decontaminant with D -values ranging from 458 to 500 Gy for nonporous items and 797–808 Gy for porous ones. The results demonstrated the successful recovery of latent marks and DNA establishing gamma irradiation as a viable decontamination option.     

An investigation on the secondary transfer of organic gunshot residues

Gunshot residues (GSR) are an important forensic trace in firearm-related events. Currently, routine GSR analyses focus on the detection and characterisation of the inorganic components (IGSR). The increasing prevalence of heavy metal-free ammunition challenges these current protocols and there is an increasing interest in how the organic components of GSR (OGSR) can provide complementary information. Similar to the situation with IGSR, OGSR compounds originally deposited on the shooter during the firing process may further be transferred onto another individual or surface. Hence, the aim of this study was to provide additional information regarding the risk of a secondary transfer of OGSR. Two scenarios were investigated, the first one related to the arrest process and the possibilities of a secondary transfer arising between a shooter onto a non-shooter (e.g. between a police officer and a person of interest (POI)). The second scenario concerned the transfer of OGSR onto the non-shooter after handling a firearm for few minutes without discharging it. One calibre was chosen, the .40 S&W calibre, used by several Australian State police forces. A secondary transfer was observed in all cases for the two scenarios investigated, for three compounds of interest: ethylcentralite (EC), diphenylamine (DPA), N-nitrosodiphenylamine (N-nDPA). The firearm handling scenario resulted in a larger secondary transfer to that of the arrest scenario. Overall, the amounts of OGSR detected on the non-shooter were generally lower than that detected on the shooter and controls after the arrest scenario. The results of this study provide complementary knowledge about OGSR, which can be further used to improve the current practice and the interpretation of OGSR evidence. In particular, it highlights that the secondary transfer proposition must be considered during the interpretation of forensic findings, especially when small amounts of OGSR target compounds are detected.