Validation of a 21-locus autosomal SNP multiplex for forensic identification purposes

A single nucleotide polymorphism (SNP) multiplex has been developed to analyse highly degraded and low copy number (LCN) DNA template, i.e. <100 pg, for scenarios including mass disaster identification. The multiplex consists of 20 autosomal non-coding loci plus Amelogenin for sex determination, amplified in a single tube PCR reaction and visualised on the Applied Biosystems 3100 capillary electrophoresis (CE) system. Allele-specific primers tailed with shared universal tag sequences were designed to speed multiplex design and balance the amplification efficiencies of all loci through the use of a single reverse and two differentially labelled allele denoting forward universal primers. As the multiplex is intended for use with samples too degraded for conventional profiling, a computer program was specifically developed to aid interpretation. Critical factors taken into account by the software include empirically determined extremes of heterozygous imbalance (Hb) and the drop-out threshold (Ht) defined as the maximum peak height of a surviving heterozygous allele, where its partner may have dropped out. The discrimination power of the system is estimated at 1 in 4.5 million, using a White Caucasian population database. Comparisons using artificially degraded samples profiled with both the SNP multiplex and AMPFISTR SGM plus (Applied Biosystems) demonstrated a greater likelihood of obtaining a profile using SNPs for certain sample types. Saliva stains degraded for 147 days generated an 81% complete SNP profile whilst short tandem repeats (STRs) were only 18% complete; similarly blood degraded for 243 days produced full SNP profiles but only 9% with STRs. Reproducibility studies showed concordance between SNP profiles for different sample types, such as blood, saliva, semen and hairs, for the same individual, both within and between different DNA extracts.     

Measurement Properties of the Communities That Care<Superscript>®</Superscript> Youth Survey Across Demographic Groups

Prevention science has produced information about risk and protective factors that predict adolescent drug use and related problem behaviors. This paper investigates the Communities That Care Youth Survey that measures multiple risk and protective factors. Using a sample of 172,628 students who participated in surveys administered in seven states in 1998, analyses were conducted to test the factor structure of these risk and protective factors and to test the equivalence of the factor models across five racial/ethnic groups (African Americans, Asians or Pacific Islanders, Caucasians, Hispanic Americans, and Native Americans), four grade levels (6th, 8th, 10th, and 12th) and both gender groups. Results support the construct validity of the surveys risk and protective factor scales and indicate that the measures are equally reliable across males and females and five racial/ethnic groups. Implications of these findings for science-based prevention planning are discussed.     

Information,apprehension, and deterrence: Exploring the limits of police productivity

The capacity of police departments to solve crimes and apprehend offenders is low for many types of crime, particularly crimes of profit. This article reviews a variety of studies of police apprehension and hypothesizes that an important determinant of the ability of the police to apprehend criminals is information. The complete absence of information for many types of crime places fairly clear upper bounds on the ability of the police to effect solutions.To discover whether these boundaries are high or low we analyzed data from the 1973 National Crime Panel about the types and amount of information potentially available to police through victim reports and patrol activities. The evidence suggests that if the police rely on information made readily available to them, they will never do much better than they are doing now. On the other hand, there appears to be more information available to bystanders and passing patrols than currently is being used, which suggests that surveillance strategies and improved police methods for eliciting, recording, and analyzing information supplied by victims and witnesses might increase the probability of solving crimes and making arrests. In light of this we review a few possibly helpful innovations suggested in the literature on police productivity and procedure.     

Fear and criminal victimization among elderly public housing residents

The influence of crime among the elderly was investigated in this study. The study suggests that crime prevention programs among the elderly should be implemented with some reservations. Since the risks of criminal victimization are low among the elderly, it may not be possible to reduce those rates much further, even with elaborate security programs for the elderly. On the contrary, raising the salience of crime by placing great emphasis on preventive behavior may well foster social isolation among the elderly.