The effects of skeletal preparation techniques on DNA from human and non-human bone

The forensic pathologist increasingly relies on the forensic anthropologist to be the consulting expert in human identification. Likewise, if identification is not possible from visual inspection of skeletal remains, the forensic biologist may be called upon to conduct DNA analysis. The possibility of downstream DNA testing needs to be considered when skeletal preparation techniques are employed to deflesh human remains, as they have the potential to strongly impact genetic analyses and subsequent identification. In this study, three cleaning techniques, boiling bone in water, in bleach, and in powdered detergent/sodium carbonate, were tested for their effect on nuclear and mtDNA recovery from a variety of human and non-human bones. A statistically significant reduction in DNA yields occurred in non-human bones cleaned with bleach, and DNA degradation was apparent electrophoretically. The human bones also showed much lower yields from bleach cleaning, while the detergent/carbonate method allowed the largest segments of DNA to be amplified, indicating it may have a less degradative effect on bone DNA than either of the other cleaning processes.     

Empirical analysis of the STR profiles resulting from conceptual mixtures

Samples containing DNA from two or more individuals can be difficult to interpret. Even ascertaining the number of contributors can be challenging and associated uncertainties can have dramatic effects on the interpretation of testing results. Using an FBI genotypes dataset, containing complete genotype information from the 13 Combined DNA Index System (CODIS) loci for 959 individuals, all possible mixtures of three individuals were exhaustively and empirically computed. Allele sharing between pairs of individuals in the original dataset, a randomized dataset and datasets of generated cousins and siblings was evaluated as were the number of loci that were necessary to reliably deduce the number of contributors present in simulated mixtures of four or less contributors. The relatively small number of alleles detectable at most CODIS loci and the fact that some alleles are likely to be shared between individuals within a population can make the maximum number of different alleles observed at any tested loci an unreliable indicator of the maximum number of contributors to a mixed DNA sample. This analysis does not use other data available from the electropherograms (such as peak height or peak area) to estimate the number of contributors to each mixture. As a result, the study represents a worst case analysis of mixture characterization. Within this dataset, approximately 3% of three-person mixtures would be mischaracterized as two-person mixtures and more than 70% of four-person mixtures would be mischaracterized as two- or three-person mixtures using only the maximum number of alleles observed at any tested locus.     

Assessing Market Power: The Trade-off Between Market Concentration and Multi-Market Participation

This analysis reveals that traditional market power measuresare biased under the conditions of multi-market participationand demand interdependence. Specifically, when complementary(substitutable) demands dominate, traditional market power measuresare biased upward (downward). A similar bias carries over tothe evaluation of mergers. To wit, mergers that simultaneouslyincrease market concentration and multi-market participationcan result in lower prices even in the absence of merger economies.It follows that merger guidelines that place undue emphasison market concentration can lead policymakers to block (approve)mergers that enhance (diminish) consumer welfare.     

Cognitive-behavioral rehabilitation for high-risk violent offenders: an outcome evaluation of the violence prevention unit

Rehabilitation programs for adult violent offending are still novel, and few published studies examine the recidivism outcomes of those who complete such programs. This study describes a New Zealand prison program for high-risk violent men. The program is intensive and cognitive behavioral. Preliminary outcome data are presented for three indices during 2 or more years of follow-up: nonviolent reconviction, violent reconviction, and subsequent imprisonment. In comparison with untreated offenders, treated men were less likely to be reconvicted of a violent offense, and those who were took longer to fail. There was also a 12% difference in favor of the treated men on the two other indices, nonviolent reconviction and reimprisonment. The authors conclude that the program shows early promise and that further evaluation with a larger sample of treated men will be important in clarifying whether the program is having a differential impact on violent versus nonviolent offending.