Forensic comparison of soils by bacterial community DNA profiling

This preliminary investigation has shown that a soil microbial community DNA profile can be obtained from the small sample of soil recovered from the sole of a shoe, and from soil stains on clothing. We have also shown that these profiles are representative of the site of collection and therefore could potentially be used as associative evidence to prove a link between suspects and crime scenes. Soil community profiles were obtained using the T-RFLP fingerprinting method that uses fluorescent primer technology and semi-automated analysis techniques similar to those used in human DNA profiling in forensic laboratories.     

Keeping Secrets From Parents: Longitudinal Associations of Secrecy in Adolescence

A 2-wave survey study among 1173 10–14-year-olds tested the longitudinal contribution of secrecy from parents to psychosocial and behavioral problems in adolescence. Additionally, it investigated a hypothesized contribution of secrecy from parents to adolescent development by examining its relation with self-control. Results showed that keeping secrets from parents is associated with substantial psychosocial and behavioral disadvantages in adolescence even after controlling for possible confounding variables, including communication with parents, trust in parents, and perceived parental supportiveness. Contrary to prediction, secrecy was also negatively associated with feelings of self-control. Secrecy from parents thus appears to be an important risk factor for adolescent psychosocial well-being and behavioral adjustment.PhD student, Department of Social Psychology, Free University, The Netherlands. Received Masters degree in social psychology at Utrecht University. Research interests are workings and consequences of secrecy in adolescence and adulthood, and evolutionary approaches to studying human social behavior.Associate Professor, Department of Social Psychology, Free University, The Netherlands. Received PhD in clinical and social psychology at the University of Louvain, at Louvain-la-Neuve. Research interests are communication and relationships in adolescence and the conceptualization and measurement of secrecy.Assistant Professor, Institute of Family and Child Care Studies, University of Nijmegen, The Netherlands. Research interests are family, work-stress, and methodological issues in multivariate longitudinal analyses.Professor, Institute of Family and Child Care Studies, University of Nijmegen, The Netherlands. Research interests are friendships, family relationships, and substance use and abuse in adolescence.     

Influences of Risk Behaviors on the Quality of Peer Relations in Adolescence

The majority of young people experiment with alcohol use, smoking, drug use, and delinquency. In order to understand why adolescents are engaged in potential risk behaviors, it is important to look at the functions of these behaviors for adolescents' social and personal functioning. In this study, we examined whether substance use, transgressive behavior, and delinquency are related to the quality of peer relations. Univariate analyses of data of a study on five hundred eight 12–18-year-olds showed that substance use and transgressive behavior are positively related to both the quantity (chumship, size of network, and time spent with peers) and the quality (attachment, support, acceptance, and competence) of peer relations. The association with peer relations were less straightforward for adolescent delinquency. Hierarchical regression analyses, however, showed that when the associations of quantitative aspects of peer relations are controlled for, no additional effects of substance use and transgressive behavior emerged. This suggests that social functions of risk behaviors may be understood as providing the opportunity to intensify contacts with peers or initiate new relations that, in turn, may be related to peer relations in a positive sense.     

Evaluation of haplotype discrimination capacity of 35 Y-chromosomal short tandem repeat loci

The haplotype discrimination capacity of the 9 Y-chromosomal short tandem repeat (Y-STR) loci comprising the so called minimal haplotype together with additional 26 recently described single-copy Y-STRs was evaluated within 391 males from Germany, The Netherlands, and Turkey. The aim of this study was to identify the minimum number of Y-STRs needed in addition to the recommended 9 minimal haplotype loci or the 11 SWGDAM loci for individualizing male lineages. Highest gene diversities were shown for DYS385 loci, DYS449, DYS481, DYS570, DYS447, DYS576, DYS389-II, and DYS390 (D=0.7518-0.8746). The five Y-STRs DYS447, DYS449, DYS481, DYS570, and DYS576 comprised the smallest set of loci in addition to the previously recommended standard Y-STRs leading to the individualization of all males from each single population group. Complete resolution of the pooled population was achieved by the additional genotyping of two further loci, DYS446 or DYS505 and DYF406S1 or DYS522.