A systematic approach to improve downstream single-cell analysis for the DEPArray™ technology

Most commercially available STR amplification kits have never been fully validated for low template DNA analysis, highlighting the need for testing different PCR kits and conditions for improving single-cell profiling. Here, current strategies rely mainly on adjusting PCR cycle number and analytical threshold settings, with a strong preference for using 30 amplification cycles and thresholds at 30–150 RFU for allele detection. This study aimed to (1) determine appropriate conditions for obtaining informative profiles utilizing a dilution series, and (2) test the outcome on single cells using the DEPArray™ technology. Four routinely applied forensic STR kits were compared by using three different amplification volumes and DNA dilutions down to 3.0 pg, while two well-performing kits were used for single/pooled leucocyte and sperm cell genotyping. Besides reduced costs, the results demonstrate that a 50%–75% PCR volume reduction was beneficial for peak height evaluation. However, this was counteracted by an increased artifact generation in diluted DNA volumes. Regarding profile completeness, the advantage of volume reduction was only prominent in samples processed with Fusion 6C. For single and pooled cells, ESIFast and NGMDetect provided a solid basis for consensus profiling regarding locus failure, although locus dropouts were generally observed as stochastic events. Amplification volume of 12.5 μL was confirmed as appropriate in terms of peak heights and stutter frequencies, with increased stutter peaks being the main artifact in single-cell profiles. Limitations associated with these analyses are discussed, providing a solid foundation for further studies on low template DNA.     

Psychopathy among condemned capital murderers

Psychopathy is an important forensic mental health construct. Despite this importance, the research base of psychopathy among individuals convicted of capital murder is limited. Archival data were collected from a sample of 636 persons convicted of capital murder and sentenced to death in the State of California. Psychopathy was assessed using the Psychopathy Checklist – Revised (PCL-R) instrument. Data on criminal careers and other behavioral disorders were also extracted. The sample mean PCL-R total score was 23.31 (SD = 9.92) and one-third of individuals in this sample were considered clinically psychopathic with PCL-R total scores of 30 or greater. Factor analytic examination yielded support for four facets: affective, interpersonal, lifestyle, and antisocial. Criterion validity findings revealed positive correlations of psychopathy scores with Antisocial Personality Disorder (ρ = 0.72), Conduct Disorder (ρ = 0.46), sexual sadism (ρ = 0.24), Oppositional Defiant Disorder (ρ = 0.20), ADHD (ρ = 0.15), arrest charges (r = 0.56), prison sentences (r = 0.53), and age of arrest onset (r = −0.57). Individuals convicted of capital murder and sentenced to death reflect heterogeneity in psychopathy with some individuals exhibiting pronounced psychopathic features.     

Accuracy of comparison decisions by forensic firearms examiners

This black box study assessed the performance of forensic firearms examiners in the United States. It involved three different types of firearms and 173 volunteers who performed a total of 8640 comparisons of both bullets and cartridge cases. The overall false-positive error rate was estimated as 0.656% and 0.933% for bullets and cartridge cases, respectively, while the rate of false negatives was estimated as 2.87% and 1.87% for bullets and cartridge cases, respectively. The majority of errors were made by a limited number of examiners. Because chi-square tests of independence strongly suggest that error probabilities are not the same for each examiner, these are maximum-likelihood estimates based on the beta-binomial probability model and do not depend on an assumption of equal examiner-specific error rates. Corresponding 95% confidence intervals are (0.305%, 1.42%) and (0.548%, 1.57%) for false positives for bullets and cartridge cases, respectively, and (1.89%, 4.26%) and (1.16%, 2.99%) for false negatives for bullets and cartridge cases, respectively. The results of this study are consistent with prior studies, despite its comprehensive design and challenging specimens.     

遵约与国际制度的有效性:情投意合还是一厢情愿

20世纪90年代,国际关系学与国际法学开始走上了相互借鉴、学习的道路。国际关系学者和法学研究者在遵约研究方面具有共同的议程,遵约研究已经成为国际关系理论的重要方面。遵约被国际关系学界用来衡量制度的因果影响,具有一定的客观性。但是,遵约与国际制度有效性之间并不具有必然的联系,遵约是对制度因果关系的误读。此外,认识论、方法论上及分析层次、内生性问题上也对遵约研究提出了挑战。遵约研究对制度有效性的启示在于:应该慎重选择衡量结果的指标,从而准确评估制度对国家政策和行为的因果影响。     

试论基础四国在后哥本哈根气候谈判中的立场和作用

基础四国是由中国、印度、巴西和南非四个主要发展中国家组成的气候谈判集团,鉴于其成员在发展中国家和世界上的影响力,该集团在国际气候谈判中备受关注。在构建2012年后国际气候机制的谈判中,基础四国的立场表现出了很高的协调性,但也存在一定的差异。总体而言,基础四国的出现和协调行动推动了国际气候谈判在公约框架下展开,有利于后京都气候安排的达成,但也可能促使国际气候谈判集团,特别是G77加中国的分化和重新组合。基础四国气候谈判集团出现时间尚短,其最终能够在构建后京都气候机制中发挥何种作用将取决于基础四国在应对气候变化中如何对待联合国渠道与其他渠道的关系、敦促发达国家减排的决心和能力以及是否能够保持G77加中国内部的团结性等。     

Family judges in the city of Buenos Aires: a view from within

This paper summarises the main findings of a study of gender differences in the values and attitudes of family judges carried out in Buenos Aires, Argentina. The study explored how men and women judges understood their profession and its requirements, their representation of the ideal family judge, their motivation to become family judges, the way they experienced the power they wield, and their opinion on the supposed contributions women judges might bring to the family judiciary. The study's findings were analysed in terms of Gilligan's ethic of justice/ethic of care approach. Two key results emerged. Firstly, there were no clear-cut differences between men and women in terms of their adherence to an ethic of justice or of care respectively. Secondly, distinct gender differences were apparent in the way women judges approached decision-making.     

A comparison of three shoe sole impression lifting methods at high substrate temperatures

Footwear impressions are a common form of evidence found at crime scenes, and the accurate recovery and recording of such impressions is critical for shoe sole comparison and identification. The lifting of shoe sole impressions from hot surfaces (>30°C/86°F) and in hot environments has received little attention in the literature, particularly in relation to the recovery of class and randomly acquired characteristics (RACs) required for accurate comparisons. This study addressed this knowledge gap by comparing the performance of three common impression lifters (gelatin, adhesive, and vinyl static cling film) at recovering shoe sole impressions in dust from hot flooring substrates. Dry origin dust shoe sole impressions were made on ceramic tile, galvanized metal, and laminated wood flooring using a shoe that possessed two RACs and five class characteristics present on the sole. Substrates were left in direct full sun for five hours during a summer day prior to lifting. Performance was measured by the proportion of RACs and class characteristics visible in each lifted impression. Results demonstrated that the vinyl static cling film tested performed poorly across all substrates, particularly for metal (23.8% marks recovered), including notable shrinkage of the lifted impression. In contrast, adhesive (~96% marks recovered over all substrates), and to a lesser extent gelatin (~85%), lifts were highly successful on hot substrates. These data suggest that adhesive lifts can consistently and accurately recover shoe sole impressions from hot substrates. This study contributes critical information for crime scene examiners to improve and expand evidence recovery in hot environments.     

Photographic comparison of surface topography as a viable solution when physical match is challenging

Physical matching methods are a family of well‐known methods that are utilized in order to determine whether two pieces of a tearable/breakable material used to be one object. When performing physical match of polymers, it is sometimes difficult to reach an unambiguous conclusion. This is due to various reasons. One is when the tear/fracture resides in an inaccessible or hidden‐from‐view region of the piece. Another is when the shape of the tear/fracture at the object's tear/fracture line is insufficient for deducing a complete match. Third is deficiency of material along this line. These are examples of processes where the line is affected so drastically, so that a match renders impossible. Specifically, when addressing elastic materials, the tear/fracture line may even be squashed. This may also be a reason for difficulty in performing a physical match. In this paper, a method is proposed where a match is alternatively achieved by means of photographic comparison of marks on the surface topography of the pieces‐in‐question. Comparisons of pairs of torn pieces of silicon rubber were made. The procedure involved photography of the surface topography the pieces. Then, the photographs were horizontally mirror‐flipped. Lastly, a comparison was made between two photographs: a photograph of one piece and a mirror‐flipped photograph of the opposite piece. The results show that after comparing the pieces to one another, only one unique pair turned out to be positively matched. Using the proposed method, not only the comparison is done by a more informative method (comparing to physical match), it is also more convenient, faster, less expensive, and technically simpler.     

Relevance analysis using revision identifier in MS word

Electronic documents often contain personal or confidential information, which can be used as valuable evidence in criminal investigations. In the digital investigation, special techniques are required for grouping and screening electronic documents, because it is challenging to analyze relationships between numerous documents in storage devices manually. To this end, although techniques such as keyword search, similarity search, topic modeling, metadata analysis, and document clustering are continually being studied, there are still limitations for revealing the relevance of documents. Specifically, metadata used in previous research are not always values present in the documents, and clustering methods with specific keywords may be incomplete because text‐based contents (including metadata) can be easily modified or deleted by users. In this work, we propose a novel method to efficiently group Microsoft Office Word 2007+ (MS Word) files by using revision identifier (RSID). Through a thorough understanding of the RSID, examiners can predict organizations to which a specific user belongs, and further, it is likely to discover unexpected interpersonal relationships. An experiment with a public dataset (GovDocs) provides that it is possible to categorize documents more effectively by combining our proposal with previously studied methods. Furthermore, we introduce a new document tracking method to understand the editing history and movement of a file, and then demonstrate its usefulness through an experiment with documents from a real case.