Characterization of human DNA in environmental samples

Environmental samples from indoor surfaces can be confounded by dust, which is composed largely of human skin cells and has been documented to contain roughly tens of micrograms of total DNA per gram of dust. This study complements previous published work by providing estimates of the quantity of amplifiable human DNA found in environmental samples from a typical indoor environment, categorized by the intensity of human traffic and visible quantity of dust. Dust was collected by surface swabbing standard 576 cm² areas in eight locations, and evaluated for total DNA quantity, presence of human DNA (mitochondrial and nuclear loci using conventional PCR), quantity of human nuclear DNA using quantitative PCR, and STR analysis. The total DNA content of 36 dust samples ranged from 9 to 28 ng/cm², and contained 0.2–1.1 pg/cm² of human DNA. Overall, human DNA was detected in 97% of 36 dust samples and 61% of samples yielded allele distributions of varying degrees of complexity when subjected to STR analysis. The implications of this study are twofold. First, the presence of dust in evidence can be a significant contamination source in forensic investigations because the human DNA component is of sufficient quality and quantity to produce allele calls in STR analysis. This can be effectively managed by implementing stringent protocols for collection and analysis of potential biological samples. A second implication is the use of dust as a source of evidence for identification of inhabitants within a defined location. In the latter case, a number of additional studies would be necessary to identify relevant pretreatments for environmental dust samples and to develop the necessary deconvolution techniques to separate the composite genotypes obtained.     

Student Success and Failure in a Graduate Criminology/Criminal Justice Program

Despite the burdens that students and institutions assume when underwriting educational careers, very little is known about completion rates, risk factors, and successful strategies of criminology/criminal justice (CCJ) graduate programs. Consequently, the present study tracks 287 master’s and 70 doctoral students who entered the Florida State University CCJ program during the 1991–2000 academic years. Almost two-thirds of this cohort earned an advanced degree. Younger students with higher GRE scores were more likely to complete the master’s program. Successful doctoral degree recipients tended to have lower GRE scores, be non-White, and earn their master’s degrees in-house. In terms of time-to-degree, it took over two years to earn an M.A. and slightly more than six years to negotiate the Ph.D. Implications are explored for the program, the university, and the discipline.     

Post-injection hybridization of complementary DNA strands on capillary electrophoresis platforms: A novel solution for dsDNA artifacts

Several laboratories have reported the occurrence of a split or n − 1 peak at the vWA locus in PowerPlex^® 16 and PowerPlex^® ES amplification products separated on 4- and 16-capillary electrophoresis instruments. The root cause of this artifact is post-PCR reannealing of the unlabeled, unincorporated vWA primer to the 3′-end of the tetramethylrhodamine (TMR)-labeled strand of the vWA amplicon. This reannealing occurs in the capillary post-electrokinetic injection. The split peak is eliminated by incorporation into the loading cocktail of a sacrificial hybridization sequence (SHS) oligonucleotide that is complementary to the vWA primer. The SHS preferentially anneals to the primer instead of the TMR-labeled strand of the vWA amplicon. In addition, the n − 10/n − 18 artifact that may be seen at the vWA locus was determined to be due to double-stranded amplicon formed post-electrokinetic injection into the capillary. This was also eliminated by adding in two Complementary Oligo Targets (COT1 and COT2) in addition to the SHS oligonucleotide into the loading cocktail. These three oligonucleotides are complementary to the 33 bases at the 5′-end of the unlabeled vWA amplicon strand and the 60 bases at its 3′-end and therefore compete for hybridization to the TMR-labeled amplicon strand. Incorporation of these three oligonucleotides in the Internal Lane Standard 600 (ILS600) eliminate both the split peak and n − 10/n − 18 artifact in PowerPlex^® 16 and PowerPlex^® ES amplification products without affecting sizing of alleles at the vWA locus or any locus in the PowerPlex^® 16, PowerPlex^® Y, PowerPlex^® ES, AmpFlSTR^® Profiler Plus^® ID, AmpFlSTR^® Cofiler^®, and AmpFlSTR^® SGM Plus^® kits.     

The Tarasoff dilemma in criminal court.

The duty to protect, or Tarasoff duty, has been conceptualized as arising solely in the context of a clinical setting. A recent California Supreme Court ruling in People v. Clark adds legal, clinical, and ethical dilemmas to the oftentimes contentious Tarasoff issue. Though the Tarasoff issue is but a minor legal point in Clark, a possible consequence of Clark is that a Tarasoff warning could be deemed nonconfidential and admissible in a criminal trial. Psychotherapists could therefore be testifying in criminal courts as prosecution witnesses. While the possibility of a chilling effect on patients' disclosure of violent ideation in the context of psychotherapy first caused apprehension after the California Supreme Court's 1976 decision in Tarasoff v. Regents of the University of California, this same Court's ruling in People v. Clark some 14 years later may ensure that this fear finally becomes realized.     

Defining subnational open government: does local context influence policy and practice?

Policy Sciences - What is open government? The contemporary conceptualization of open government remains rooted in transparency and accountability, but it is embedded within the political economy...