Evaluating the discriminating power of amino acid ratios on distinguishing dark colored hair samples

Human hairs are one of the most commonly encountered items of trace evidence. Currently, conventional methods for hair analysis include microscopic comparison and DNA analysis (nuclear and mitochondrial). Each approach has its own drawbacks. Hair proteins are stable and offer an alternative to DNA testing, as demonstrated with proteomics for distinguishing humans. However, proteomics is complicated and requires identifying peptides to remain intact following harsh sample preparation methods. Alternatively, the actual amino acid content of a hair sample may also offer important identifying information and actually requires proteins and peptides to be broken down completely rather than remaining intact. This study evaluated the discriminating power of using hair amino acid ratios to differentiate hair samples from 10 unrelated individuals with dark colored hair. Hair proteins were digested, derivatized, and analyzed using gas chromatography–mass spectrometry. Amino acid ratios were calculated for each individual and comparisons using ANOVA and post-hoc pairwise t-test with Bonferroni correction were made with amino acid ratios for individuals. Overall, out of the 45 possible pairwise comparisons between all hair samples, 38 (84%) were differentiable. Out of the 36 possible pairwise comparisons between brown haired individuals, 32 (89%) were considered differentiable using univariate statistics. Multivariate statistics were also attempted but, overall, univariate models were sufficient for exclusionary purposes. These results indicate that amino acid ratio analysis can potentially be used as an exclusionary method using hair if DNA analysis cannot be performed, or to corroborate conclusions made following microscopic analysis.     

The paradox of grading systems

We distinguish between (i) voting systems in which voters can rank candidates and (ii) those in which they can grade candidates, using two or more grades. In approval voting, voters can assign two grades only—approve (1) or not approve (0)—to candidates. While two grades rule out a discrepancy between the average-grade winners, who receive the highest average grade, and the superior-grade winners, who receive more superior grades in pairwise comparisons (akin to Condorcet winners), more than two grades allow it. We call this discrepancy between the two kinds of winners the paradox of grading systems, which we illustrate with several examples and whose probability we estimate for sincere and strategic voters through a Monte Carlo simulation. We discuss the tradeoff between (i) allowing more than two grades, but risking the paradox, and (ii) precluding the paradox, but restricting voters to two grades.     

Strengthening cross-border law enforcement cooperation in the EU: the Prüm network of data exchange

The Prüm network was established to provide mechanisms and the infrastructure to achieve a closer cooperation between the EU member states in combating terrorism, organised crime and illegal immigration through the cross border exchange of DNA profiles, fingerprints and vehicle registration data. While Prüm offers clear benefits for cross-border policing, it continues to present challenges of a technical and scientific nature as well as legal, ethical and socioeconomic concerns. This article reviews these challenges as well as the existing safeguards. It argues that, in order to achieve Prüm benefits and maximise its potential, it is important to enhance the necessary dialogue and cooperation between member states so as to confront the above concerns and address challenges posed by Prüm through balanced measures.     

An Examination of Reciprocal Associations Between Social Preference,Popularity, and Friendship during Early Adolescence

Getting along with peers becomes increasingly important to health and well-being during early adolescence (10–14 years). Young adolescents may succeed with peers when they are well-liked by and popular among the larger peer group (or at the group-level of social complexity). They might also fare well with peers when they are able to form numerous mutual and high quality friendships (at the dyadic-level of social complexity). Theory emphasizes the interrelatedness of different types of peer experiences, but few longitudinal studies have examined the interplay among and between group- and dyadic-level peer experiences in the same study. As a result, it is not known whether group-level peer experiences are predictors of dyadic-level peer experiences, and/or vice versa. To address this limitation, this study examined the prospective and reciprocal relations between four indices of peer experiences, preference (or being highly liked and not disliked by peers), popularity (or having a reputation as popular), friendship quantity (or having many mutual friends), and friendship or relationship quality, during early adolescence. Participants were 271 adolescents (49% girls; M_age?=?11.52 years) who completed peer nominations of preference and popularity, a self-report measure of friendship quality, and nominated friends at two waves (Wave 1: November, Grade 6; Wave 2: October, Grade 7). Structural equation modeling indicated that friendship quantity predicted increases in preference and popularity and that friendship quality predicted increases in friendship quantity. Initial popularity was associated with decreases in preference. The importance of these findings for future research is discussed along with study limitations.     

Longitudinal Links Between Identity Consolidation and Psychosocial Problems in Adolescence: Using Bi-Factor Latent Change and Cross-Lagged Effect Models

Most previous identity research has focused on relationships between identity synthesis, confusion, and psychosocial problems. However, these studies did not take into account Erikson’s notion of identity consolidation, that is, the dynamic interplay between identity synthesis and confusion. This study aimed to examine longitudinal relationships and the directionality of the effects between identity consolidation and psychosocial problems during adolescence, using two waves of longitudinal data from 793 Japanese adolescents (49.7% girls; ages 13–14 and 16–17 at Time 1). A bi-factor latent change model revealed that levels and changes in identity consolidation were negatively associated with levels and changes in psychosocial problems. Furthermore, a bi-factor cross-lagged effects model provided evidence that identity consolidation negatively predicted psychosocial problems, and vice versa. Our study facilitates a better understanding of the importance of identity consolidation in the relations between identity components and psychosocial problems.     

The Effects of Neighborhood Context on Exposure to Adverse Childhood Experiences (ACE) Among Adolescents Involved in the Juvenile Justice System: Latent Classes and Contextual Effects

Adverse childhood experiences (ACEs) have been identified as a key risk factor associated with a wide range of negative life outcomes, including juvenile delinquency. Much less work has explored whether certain combinations of ACEs, or typologies of trauma, exist, and whether or not these subgroups are differentially associated with certain youth-level and/or community-level characteristics. The current study uses latent class analysis to examine ACE typologies among a sample of over 92,000 juvenile offenders between the ages of 10 and 18 in the state of Florida (52% male, 37.3% White, 46.8% Black, 15.9% Hispanic). Multilevel multinomial logistic regression is used to assess the relationship between both individual- and community-level factors and class membership. The findings suggest that a total of five distinct ACE typologies exist among the sample of juvenile offenders, and age, race, and sex were significantly associated with class membership. Additionally, controlling for individual-level characteristics, community-level measures of immigrant concentration, residential instability, and two separate measures of concentrated disadvantage and affluence were significantly related to class membership. This study contributes to the understanding of adverse childhood experiences, and adds to existing knowledge regarding the relationship between contextual factors and childhood abuse, maltreatment, and trauma. The identification of ACE subgroups with distinct characteristics may help guide prevention strategies and tailor treatment provided by the juvenile justice system.