Developmental validation of feline, bovine, equine, and cervid quantitative PCR assays

Accurate DNA quantification is essential for optimizing DNA testing and minimizing sample consumption. Real-time quantitative polymerase chain reaction (qPCR) assays have been published for human and canine nuclear DNA, and the need for quantifying other forensically important species was evident. Following the strategy employed for the canine qPCR assay, we developed individual assays to accurately quantify feline, bovine, equine, and cervid nuclear DNA. Each TaqMan-based assay incorporates a genus-specific probe targeting the Melanocortin-1 Receptor gene and includes a piece of synthetic DNA that acts as an internal PCR control for detecting inhibition. Developmental validations were carried out following the revised guidelines of the Scientific Working Group on DNA Analysis Methods with modifications necessary for validation of nonhuman qPCR assays. All assays demonstrated the specificity, sensitivity, stability, reproducibility, accuracy, and precision required for forensic casework. The application of these assays to animal forensic DNA analysis has both conserved laboratory resources and improved genotyping results.     

Real-time polymerase chain reaction quantification of canine DNA

The accurate quantification of target DNA is an important step in the short tandem repeat analysis of forensic biological samples. By utilizing quantification data to control the amount of template DNA in the polymerase chain reaction (PCR), forensic scientists can optimize testing and minimize the consumption of limited samples. The ability to identify and quantify target DNA in mixed-species samples is crucial when it may be overwhelmed by nontarget DNA, as in cases of dog attack. We evaluated two quantitative real-time PCR assays for dynamic range, species specificity, and inhibition by humic acid. While both assays proved to be highly sensitive and discriminating, the Melanocortin-1 Receptor (MC1R) gene Taqman assay had the advantages of a shorter run time, greater efficiency, and safer reagents. In its application to forensic casework, the MC1R assay has been advantageous for quantifying dog DNA in a variety of mixed-species samples and facilitating the successful profiling of individual dogs.     

Reviving rosetta tharpe: performance and memory in the 21st century

This article examines the pleasures and dangers of the 'reviving'—that is, restoring to memory, of a 'forgotten' female gospel-guitarist, Sister Rosetta Tharpe. It argues that the erasure of black women from cultural memory is not merely the effect of the passage of time, but of small but significant acts of forgetting that themselves constitute cultural practices. As examples of attempts to forestall forgetting and 'revive' the dead, the essay looks to a recent Rosetta Tharpe tribute CD, composed of women musicians' versions of songs Tharpe made famous, as well as a local Pittsburgh theatre incorporation of Tharpe as a character in its production 4 Real Women. Both projects, although inevitably fraught by difficulties specific to their medium of performance and address, set the terms of cultural 'revival' crucial not merely to Rosetta Tharpe but to black women performers generally.     

项目反应理论参数估计研究中的蒙特卡罗方法

蒙特卡罗(Monte Carlo,MC)方法是项目反应理论(Item Response Theory,IRT)参数估计研究中的重要方法,针对目前对其的理解误区和不当应用,从MC方法的本质思想出发,系统论述了如何在IRT参数估计研究中应用MC方法,重点阐述了将之等同于统计抽样实验的思想,并结合IRT参数估计的特点,介绍了完全交叉MC实验设计方法及其结果分析方法,为MC方法在IRT参数估计研究的应用提供了理论指导。