Virtual anthropology: a preliminary test of macroscopic observation versus 3D surface scans and computed tomography (CT) scans

Virtual anthropology (VA) is based on applying anthropological methods currently used to analyse bones to 3D models of human remains. While great advances have been made in this endeavour in the past decade, several interrogations concerning how reliable these models are and what their proper use should be remain unanswered. In this research, a fundamental assumption of VA has been investigated: if the way we perceive and apply an anthropological method is truly similar when looking at bones macroscopically and through various 3D media. In order to answer, 10 skulls of known age and sex were scanned using a computed tomography (CT) scanner and a 3D surface scanner. Two observers separately applied a defined staging method to eight suture sites on these skulls, first looking at the bone macroscopically, then at the 3D surface scan, and finally on the CT scan. Two rounds of observation were carried out by each observer. Intra- and inter-observer error were evaluated, and two sample t-tests used to evaluate if the different types of medium used yielded significantly different observations. The results show a high degree of inter-observer error, and that data obtained from 3D surface scans differ from macroscopic observation (confidence level 95%, P ≤ 0.05). CT scans, in these settings, yielded results comparable to those obtained through macroscopic observations. These results offer many possibilities for future research, including indications on the kind of anthropological methods and anatomical landmarks that might be reliably transferable to the virtual environment. All current methods used in traditional anthropology should be tested, and if they prove unreliable, new techniques to analyse bones from virtual models should be developed.

Key points

• Large discrepancies between observation on dry bones and computer-generated 3D models (surface scans or CT scans) could lead to the re-evaluation of the suitability of traditional anthropological methods for application on 3D models.
• This preliminary study evaluates whether macroscopic, 3D surface scans, and CT scans viewings generate different observations.
• The results indicate that the data are not always coherent across all three media of observation.
• Explanations include the aspect given to the bone by the 3D software, differences between handling bones in real life versus on a computer, and level of expertise of the observers.

     

祖孙双单亲比对的匹配概率研究

目的推导祖孙双单亲比对的匹配概率(PMGDS)公式,并以随机模拟法进行验证。方法首先,根据定义推导PMGDS的数学公式,依据此公式在19个基因座上计算PMGDS的数值。其次,以随机模拟法设计实验,在19个基因座上计算PMGDS的模拟值。最后,以模拟值对比公式值的方式,对公式进行实验验证。结果研究获得了PMGDS的数学公式,经模拟实验验证显示出良好的符合。结论祖孙双单亲比对的错判概率较低,具有很好的应用价值。     

IgE死后生化学检测的研究现状及应用展望

过敏性休克导致死亡的案例在法医学实践中常有发生,然而由于缺少特异的病理形态学指征,导致过敏性休克死亡的法医学鉴定面临一定的困难。IgE作为介导I型超敏反应的关键介质,其死后生化学检测对过敏性休克死亡案例的法医学鉴定具有辅助作用。但在实际应用中,血液等检材常受溶血等死后变化因素影响,尤其我国尸体保存以冷冻为主,溶血程度更加严重,对IgE等生化学指标的检测造成极大干扰。本文就目前IgE死后生化学检测的研究现状、生物学检材的选取及检测方法进行综述,并对现实应用中所面临的问题进行探讨。     

Overlooking Feigning Behavior May Result in Potential Harmful Treatment Interventions: Two Case Reports of Undetected Malingering

Clinicians tend to overestimate their ability to recognize feigning behavior in psychiatric patients, especially if it concerns patients who have been admitted for observation. Feigning can be either externally motivated (e.g., for financial compensation, known as malingering) or internally motivated (e.g., to assume the “sick role,” known as factitious disorder). Persistent presentation of severe symptoms is usually associated with the factitious disorder. We present two patients with strong external incentives who consistently and convincingly feigned severe psychiatric symptoms during a protracted period of inpatient observation in a specialized center; both were engaged in a procedure for medical asylum. The first case presented with the clinical picture of a psychotic depression with severe motor symptoms, and the second case showed symptoms of a chronic post-traumatic stress disorder with secondary psychotic symptoms. Both cases were thoroughly investigated but feigning was overlooked, and unnecessary and harmful treatment interventions were given. To prevent iatrogenic damage, we recommend a critical attitude that takes malingering as an option into account in settings where patients are often involved in high stake legal procedures. A clinical sign that might indicate feigning is therapy-resistant symptoms. To rule out feigning a comprehensive, multimethod approach is required, but an active stance toward collateral information is essential. Specialized psychological tests may be useful for preliminary screening, but for their use in culturally diverse populations as in refugee mental health more research is needed.     

Evaluating the Potential for Unintentional Occupational Exposure to Fentanyl and Fentanyl Analogues Among Medicolegal Death Investigators and Autopsy Technicians

Recent increases in deaths in the United States from synthetic opioids such as fentanyl and fentanyl analogues (fentanyls) have raised concerns about possible occupational exposures to these potent agents. Medicolegal death investigators and autopsy suite staff might perform job tasks involving exposure to fentanyls. The potential for exposure to fentanyls among medicolegal death investigators and autopsy technicians at a state medical examiner's office was evaluated through review of caseload characteristics, injury and illness logs, and procedures and policies and discussions with management and employee representatives. The evaluation showed that this medical examiner's office had low potential for work-related exposure to fentanyls; its standard operating procedures and personal protective equipment requirements should reduce the potential for occupational exposure. Medicolegal death investigation agencies can develop and implement guidance to control exposures and provide workforce education and training to reduce the potential for work-related exposure to fentanyls.     

Feedback on Forensic Mental Health Assessments in a Juvenile Court Clinic Certification Program

Public-sector mental health systems have set forth specialized practice competencies for forensic mental health clinicians conducting court-ordered examinations. This study examined a sample of feedback letters to clinicians who submitted mid-training and final reports for review as part of the requirements for certification as a juvenile court clinician. The most common feedback points were insufficient/irrelevant historical data, problems with clarity/organization of the report, problems with interview/mental status examination, and problems with competency to stand trial data/opinions. Clinicians had fewer deficiencies in their final report compared to their mid-training report, supporting the perspective that forensic training and supervision is associated with better quality reports.     

Two-dimensional metric comparisons between dynamic bare footprints and insole foot impressions-forensic implications

Footwear may be found at crime scenes as physical evidence. Such footwear often has impression features of the wearer’s foot on the insole of the shoe. Scientific research and literature have established that footprints are distinct. This study compares two-dimensional measurements on bare footprints to foot impressions on insoles to determine if significant differences or similarities exist. Dynamic footprints were collected from 51 donors using the Identicator® Inkless Shoe Print Model LE 25P system. Seven foot length and width measurements were taken based on the Reel linear measurement method. Footprint measurements between bare footprints and foot impressions on the insoles were compared. Only two differences (p > 0.05) were observed between the various bare footprint and insole foot impression measurements on the right and left side for most of the measurements, CALC (p < 0.001) and A1 (p = 0.04). Bare footprint and insole A5 measurements on the left side were also significantly different (p = 0.015). The results of the study have implications in the forensic analysis of foot impression evidence on insoles in footwear in assisting with identifying the wearer of said footwear. Situations may arise in the forensic context when comparing the foot impression on the insole of footwear to a suspect’s bare footprint or a footprint from post-mortem remains. This study contributes to the scant literature available on the topic and to understanding the similarities and differences observed in the various linear measurements that may be utilized in the comparison process of footprint impressions on shoe insoles to bare footprints.     

Prevalence of organic gunshot residues in police vehicles

The present study investigated the organic gunshot residue (OGSR) background level of police vehicles in Switzerland. Specimens from 64 vehicles belonging to two regional police services were collected and analysed by LC-MS in positive mode. The driver’s and back seats were sampled separately to monitor potential differences between locations and to assess the risks of a suspect being contaminated by OGSR during transportation to a police station.The results showed that most of the 64 vehicles were uncontaminated (44 driver’s seats and 38 back seats respectively). Up to six of the seven targeted compounds were detected in a single sample, once on a driver’s seat and twice on back seats. The contamination frequency generally decreased as the number of compounds detected together increased. The amounts detected were in the low ng range and less than amounts generally detected just after discharge on a shooter. Our data indicated that detecting a combination of four or more compounds on a police vehicle seat appears to be a relatively rare occurrence. The background contamination observed was most probably due to secondary transfer from police officers (e.g. through recent participation in a shooting session or firearm manipulation) or from firearms stored in the vehicles. The present results might be used as a recommendation to minimize contact of a suspect with contaminated surfaces if OGSR is implemented in routine work in parallel to IGSR analysis.     

Gaughran vs the UK and public acceptability of forensic biometrics retention

This commentary provides a response to the European Court of Human Rights ruling in the case of Gaughran vs the United Kingdom on 13 February 2020. The Court ruled that the indefinite retention of DNA, fingerprints and facial images from all convicted adults was disproportionate. Using data from a survey on public attitudes, we examine the public acceptability of the police retention of forensic biometrics from the population.