Simplified low-copy-number DNA analysis by post-PCR purification

Frequently, evidentiary items contain an insufficient quantity of DNA to obtain complete or even partial DNA profiles using standard forensic gentotyping techniques. Such low-copy-number (LCN) samples are usually subjected to increased amplification cylces to obtain genetic data. In this study, a 28-cycle polymerase chain reaction (PCR) was used to evaluate various methods of post-PCR purification for their effects on the sensitivity of fluorophore-based allelic detection subsequent to capillary electrophoretic separation. The amplified product was purified using filtration, silica gel membrane, and enzyme mediated hydrolysis purification techniques and evaluated for their effect on fluorescent allelic signal intensity. A purification method was selected and its effect on fluorescent allelic signal intensity was compared with that of the unpurified PCR product. A method of post-PCR purification is described which increases the sensitivity of standard 28-cycle PCR such that profiles from LCN DNA templates (<100 pg DNA) can be obtained. Full DNA profiles were consistently obtained with as little as 20 pg template DNA without increased cycle number. In mock case type samples with dermal ridge fingerprints, genetic profiles were obtained by amplification with 28 cycles followed by post-PCR purification whereas no profiles were obtained without purification of the PCR product. Allele dropout, increased stutter, and sporadic contamination typical of LCN analysis were observed; however, no contamination was observed in negative amplification controls. Post-PCR purification of the PCR product can increase the sensitivity of capillary electrophoresis to such an extent that DNA profiles can be obtained from <100 pg of DNA using 28-cycle amplification.     

Ten methods for calculating the uncertainty of measurement

While forensic laboratories are coming under increasing pressure to provide meaningful estimates of measurement uncertainty, there has been little discussion of this topic in the literature. This article summarizes ten bases for estimating this parameter: (1) proficiency tests; (2) readability limits; (3) independent reference materials; (4) operational limits applied during calibration; (5) expert judgment; (6) precision control samples without (6) and with (7) contributions from extramural sources of error; (8) error budgets; (9) historical performance; and (10) ruggedness tests. Based on the assumptions underlying each approach, the forensic community will need to apply a variety of discipline-specific approaches to arrive at satisfactory estimates of measurement uncertainty.     

Experiences of Incarcerated Veterans in an All-Veterans Housing Unit: a Qualitative Study

Many US veterans leave military service with a variety of psychosocial risk factors stemming from readjustment to civilian life, and there is increased public concern about the incarceration of veterans given ongoing conflicts in Iraq and Afghanistan. Prisons are playing instrumental roles in developing interventions to address the problems justice-involved veterans face both psychologically and environmentally in the form of veterans’ service units (VSUs), dormitories developed to assist with community reintegration, and connecting veterans to medical and mental health services. This study uses qualitative data from 87 veterans on a VSU who participated in a program improvement survey asking about their programming and reentry needs, experiences on the unit compared to other units, and any suggestions for improvement. Qualitative analysis of responses identified several themes including veterans’ needs around physical fitness, job training, education, and mental health and substance abuse treatment; positive experiences on the VSU compared to traditional units; the positive partnership role with the State Department of Corrections and the local Veterans Affairs (VA) medical center; and concerns on the unit about VA eligibility, combat status, and “real veterans.” These results are some of the first to capture the experiences of veterans on a VSU and the findings highlight potential benefits and challenges with implementing VSUs. Greater research and evaluation are needed to develop more treatment-oriented, rehabilitative models of justice and to continue to refine the VSU model.     

The effectiveness of supermarket posters in helping to find missing children

One approach used to help find missing children is to place posters of them at the exits of supermarkets. The present research addresses the question of how effective that approach is likely to be. Posters of 8 missing children were displayed on a bulletin board at a cooperating grocery store. Customers leaving the store completed a survey and took a recognition memory test for the children. Most customers thought the problem of missing children was an important issue. However, the majority of customers also reported either not looking at the posters or only briefly looking at the posters. Recognition memory for children depicted in the posters did not reliably differ from chance. It appears that there is much room for improvement when it comes to increasing the attention paid to posters meant to help find missing children.     

Real Estate Markets Are Informationally Efficient: Evidence from Buyer and Agent/Broker Surveys

This article presents new evidence based on unpublished buyer surveys and real estate agent and broker surveys supporting the consensus in the published literature that real estate markets are informationally efficient. This evidence is drawn from expert reports submitted in litigation involving claims that contamination caused property value diminution, and presents a new hedonic regression model of residential sales prices that includes as an independent variable the state of knowledge of the buyer regarding a contamination event. In this model the state of knowledge of the buyer has no statistically significant effect on the sales price. The article also discusses standards for the use of buyer and agent/broker surveys in litigation.     

Organizational change in law enforcement

A major problem in identifying and understanding change in law enforcement organizations is in specifying the object of intended change and the process by which change is to be implemented. The study focuses on organizational-structural change in police organizations and examines factors which have influenced the implementation of saturation patrol units, covert surveillance units, and regionalized detective bureaus. The results indicate that factors such as domain consensus, dependence and influence relationships, and perceptions of threat affect both the acceptance and use of these organizational changes.