Forensic isoscapes based on intra-individual temporal variation of δ18O and 206Pb/207Pb in human teeth

Isotopic signatures used in the georeferencing of human remains are largely fixed by spatially distinct geologic and environmental processes. However, location-dependent temporal changes in these isotope ratios should also be considered when determining an individual’s provenance and/or trajectory. Distributions of the relevant isotopes can be impacted by predictable external factors such as climate change, delocalisation of food and water sources and changes in sources and uses of metals. Using Multi-Collector Inductively-Coupled Plasma Mass Spectrometer (MC-ICP-MS) analyses of ²⁰⁶Pb/²⁰⁷Pb in tooth enamel and dentin from a population of 21 ± 1-year-old individuals born circa 1984 and isotope ratio mass spectrometry (IRMS) of δ¹⁸O in their enamel, we examined the expected influence of some of these factors. The resulting adjustments to the geographic distribution of isotope ratios (isoscapes) found in tooth enamel and dentin may contain additional useful information for forensic identification, but the shifts in values can also impact the uncertainty and usefulness of identifications if they are not taken into account.

KEY POINTS

• Isoscapes of ²⁰⁶Pb/²⁰⁷Pb and δ¹⁸O used for geolocation are not static.
• Within a few years, the enamel and dentin of a person may exhibit measurable differences in ²⁰⁶Pb/²⁰⁷Pb even without changing locations.
• Changes in climatic patterns tied to rising temperatures are more significant than the direct effect of increasing temperature on δ¹⁸O fixed in tooth bioapatite.
• Third molar (M3) enamel mineralisation includes material incorporated from before formal amelogenesis takes place.

     

The Impact of Gender Identity on Female Offending: A Quantitative Assessment Using the BSRI

Despite considerable research showing the importance of masculinity in male offending, the role of gender identity in female offending remains unclear. The current study explores the impact of gender identity on female offending among a sample of 843 college women using the Bem Sex Role Inventory and Multiple Problem Behavior Index. The impact of gender identity on rates of general deviance, as well as behaviors typically in high male and female participation, aggression and self-harming, respectively, were examined. Results found that women with masculine identity were more likely to engage in aggression as well as general deviance broadly. Gender identity was not found to impact rates of self-harming.     

Behavioural case linkage with solved and unsolved crimes

Offender behaviour is used to distinguish between crimes committed by the same person (linked crimes) and crimes committed by different people (unlinked crimes) through behavioural case linkage. There is growing evidence to support the use of behavioural case linkage by investigative organisations such as the police, but this research is typically limited to samples of solved crime that do not reflect how this procedure is used in real life. The current paper extends previous research by testing the potential for behavioural case linkage in a sample containing both solved and unsolved crimes. Discrimination accuracy is examined across crime categories (e.g. a crime pair containing a car theft and a residential burglary), across crime types (e.g. a crime pair containing a residential burglary and a commercial burglary), and within crime types (e.g. a crime pair containing two residential burglaries) using the number of kilometres (intercrime distance) and the number of days (temporal proximity) between offences to distinguish between linked and unlinked crimes. The intercrime distance and/or the temporal proximity were able to achieve statistically significant levels of discrimination accuracy across crime categories, across crime types, and within crime types as measured by Receiver Operating Characteristic (ROC) analysis. This suggests that behavioural case linkage can be used to assist the investigation, detection and prosecution of prolific and versatile serial offenders.     

Migration,citizenship and autochthony: strategies and challenges for state-building in Côte d'Ivoire

Although migration has for some time been an important topic in African studies, the ‘politics of migration’ remain relatively under-examined. While there is a substantial body of literature on migration and economic development, we know much less about the impact of migration on other state-building processes. The upsurge of autochthony discourses throughout much of Africa is a recent phenomenon and an alarming trend that reveals the increased politicisation of migration and the challenge these discourses pose to state-building. This article uses Côte d'Ivoire as a case study to shed light on the complex relationship between migration and state-building. It also provides a fresh perspective on a new chapter in Ivoirian politics as it re-examines this relationship in light of the recent political developments following the 2010 elections. In so doing, it provides new insights into the enduring nature of autochthony, highlighting the contemporary challenges that these discourses pose for both migrants and state-building.     

Sequential lineup presentation promotes less-biased criterion setting but does not improve discriminability

When compared with simultaneous lineup presentation, sequential presentation has been shown to reduce false identifications to a greater extent than it reduces correct identifications. However, there has been much debate about whether this difference in identification performance represents improved discriminability or more conservative responding. In this research, data from 22 experiments that compared sequential and simultaneous lineups were analyzed using a compound signal-detection model, which is specifically designed to describe decision-making performance on tasks such as eyewitness identification tests. Sequential (cf. simultaneous) presentation did not influence discriminability, but produced a conservative shift in response bias that resulted in less-biased choosing for sequential than simultaneous lineups. These results inform understanding of the effects of lineup presentation mode on eyewitness identification decisions.     

Going Maverick: How Candidates Can Use Agenda-Setting to Influence Citizen Motivations and Offset Unpopular Issue Positions

Holding an unpopular position on an issue important to voters can endanger a candidate??s electoral success. What is the candidate??s best agenda-setting strategy? To focus on other issue positions congruent with the same ideological stereotype, shoring up support among like-minded voters? Or to ??go maverick?? by discussing some issues that signal liberal positions and some that signal conservative positions? Existing voting models suggest the answer depends on voter preferences, since going maverick should have symmetric effects??support among voters who agree with the candidate??s positions will decrease, proportionally, as support increases among voters who disagree. We argue, however, that stereotype incongruence prompts these voters to process information differently, yielding asymmetric effects. We test our expectations experimentally, using a fictional candidate webpage to show how the benefits of going maverick can outweigh the costs.     

The tendency of individuals to transfer DNA to handled items

This research investigates factors influencing the transfer of DNA to handled objects and the process known as 'shedding'. Volunteers were recruited to hold sterile plastic tubes using experiments originally designed by Lowe et al. [A. Lowe, C. Murray, J. Whitaker, G. Tully, P. Gill, The propensity of individuals to deposit DNA and secondary transfer of low level DNA from individuals to inert surfaces, Forensic Sci. Int. 129 (2002) 25-34]. Transferred cellular material was collected from the tubes and STR profiles generated using the AmpFlSTR SGM Plus multiplex with 28 and 34 PCR cycles. Volunteers were asked to hold the tubes with each hand, and to participate in a series of handwashing experiments. The DNA profiling results obtained from the transferred skin cells were compared. An attempt was made to characterize the volunteers as 'good' or 'bad' shedders and to establish which, if any, of the experimental variables were associated with 'good' shedding. Our results suggest that many factors significantly influence shedding, including which hand an individual touches an item with and the time that has elapsed since they last washed their hands. We have found that it may be more complicated than previously reported to categorise a person as being either a 'good' or a 'bad' shedder and that if truly 'good' shedders exist they may be significantly rarer than some have estimated. In the current research no 'good' shedders were observed in a group of 60 volunteers. Given these results, it seems that rather than being applied to individual forensic cases, knowledge of shedding characteristics will be most useful in providing general background data for the interpretation of trace DNA evidence.