Evaluation of sieving polymers for fast, reproducible electrophoretic analysis of short tandem repeats (STR) in capillaries

Efficient capillary electrophoretic STR analysis requires rapid, reproducible and robust separation of DNA fragments with reasonable capillary longevity--this is currently accomplished using proprietary commercial polymeric sieving matrices specifically developed for this separation. These matrices, while effective, are costly and do not provide adequate resolution of STR DNA fragments in capillaries with shorter effective separation lengths, increasing the time required to accomplish the separation and minimizing the potential extrapolation to other miniaturized platforms. As the forensic community looks toward next generation microchip technology as a means of processing casework more rapidly, new sieving polymers need to be evaluated for utilization in this platform. The research presented here describes the assessment of commercially-available polymeric sieving matrices for STR analysis, with consideration given to feasibility of incorporation into a microdevice. Polymer composition, molecular weight, and concentration were evaluated, along with an assessment of the effects of buffer composition, separation temperature, and capillary length. These variables were evaluated individually or collectively on the ability to resolve STR DNA fragments and the reproducibility of the separations and the results compared to a proprietary commercial product. A 600,000 Da MW poly(ethylene oxide) (PEO) solution at a 3% (w/v) concentration was determined to be the most suitable matrix for these separations. This polymer, in coated capillaries, provided highly robust and reproducible separations, with near baseline resolution of fragments having single base differences. Reductions in the temperature of the separation, from 60 degrees C to 40 degrees C, and the urea concentration of the buffer, from 7 M to 3.5 M, provided increased longevity of the PEO polymer for repeated separations. Comparison of this polymer with currently specified commercial products used for STR analysis showed that the optimized PEO matrix provided superior separations under all conditions tested. In addition, PEO could be utilized in shorter capillary systems, with a concurrent decrease in analysis time, highlighting its potential for use in shortened capillary or microdevice systems.     

STR analysis of artificially degraded DNA-results of a collaborative European exercise

Degradation of human DNA extracted from forensic stains is, in most cases, the result of a natural process due to the exposure of the stain samples to the environment. Experiences with degraded DNA from casework samples show that every sample may exhibit different properties in this respect, and that it is difficult to systematically assess the performance of routinely used typing systems for the analysis of degraded DNA samples. Using a batch of artificially degraded DNA with an average fragment size of approx. 200 bp a collaborative exercise was carried out among 38 forensic laboratories from 17 European countries. The results were assessed according to correct allele detection, peak height and balance as well as the occurrence of artefacts. A number of common problems were identified based on these results such as strong peak imbalance in heterozygous genotypes for the larger short tandem repeat (STR) fragments after increased PCR cycle numbers, artefact signals and allelic drop-out. Based on the observations, strategies are discussed to overcome these problems. The strategies include careful balancing of the amount of template DNA and the PCR cycle numbers, the reaction volume and the amount of Taq polymerase. Furthermore, a careful evaluation of the results of the fragment analysis and of automated allele calling is necessary to identify the correct alleles and avoid artefacts.     

Self-esteem and delinquency

Cross-lagged panel correlation technique is used to examine whether self-esteem has a greater effect on delinquency than delinquency has on self-esteem. Analysis of a nationwide study of tenth-grade boys shows that self-esteem is the more powerful causal factor, even when initial levels of delinquency are held constant. This result, however, is found to be stronger in the lower class than in the upper class. These data are interpreted as lending greater support to Kaplan's theory of the self-enhancing nature of delinquent behavior than to the idea of reflected appraisals.The research reported in this article was funded by a grant from the National Institute of Mental Health (MH27747), which is gratefully acknowledged. The data and tabulations utilized in this article were made available (in part) by the Institute for Social Research Social Science Archive. The data were originally collected by Dr. Jerald G. Bachman, Survey Research Center, Institute for Social Research, The University of Michigan. Neither the original collector of the data nor the archive bears any responsibility for the analyses or interpretations presented here.This article is a revised version of a paper presented at the annual meeting of the Eastern Sociological Society, Philadelphia, April 2, 1978.Received her Ph.D. from the University of Maryland and is interested particularly in the social influence on the self-concept.Received his Ph.D. from Columbia University and is interested in the structure and development of the self-concept.Received her Ph.D. from Stanford University. Current research interests are related to a longitudinal study of personality development.     

Managing Racial Diversity: Matching Internal Strategies with Environmental Needs

Although demographic diversity has been of paramount concern to researchers and practitioners in public management, studies exploring managerial strategies to capitalize on and respond to the needs of diverse client populations are scarce. This article examines strategies for managing diversity as a way to buffer environmental challenges in service delivery and performance resulting from heterogeneous client demands. Findings suggest that administrators prioritize diversity efforts when faced with higher levels of regulatory violations (a performance measure). A higher percentage of black residents is associated with lower service quality. However, the effect of managerial strategies for diversity on performance is conditioned by the racial composition of the clients: as the percentage of black nursing home residents increases, diversity management efforts are associated with a lower number of regulatory violations. Similarly, at higher levels of racial heterogeneity, diversity management efforts are associated with fewer regulatory violations.     

Employee Perceived Effect of Leadership Training: Comparing Public and Private Organizations

This study reports on the effectiveness of a year-long field experiment involving training in transformational and transactional leadership in the public and private sectors. Using before and after training assessments by employees of several hundred Danish leaders, the analysis shows that transformational leadership training is associated with increases in behaviors linked to both transformational leadership and the use of verbal rewards, but only for public sector organizations. There is no impact in private sector organizations. Transactional leadership training appears to be equally effective in stimulating the use of pecuniary rewards in both public and private organizations.     

A MODEL FOR TELEPHONE MEDIATION

A unique mediation service using the telephone to help parents resolve conflicts over visitation ("access") is described. The program presented special advantages of low cost and high responsiveness to parents and their children and was designed to particularly benefit families that lacked the mobility or financial resources to participate in traditional face-to-face mediation. Because the service featured highly educated and experienced mediators and a child-focused, principle-based mediation approach, family members received reframing, refocusing, informative, and empathic assistance in understanding and dealing with their parenting disputes. Some 700 families and nearly 900 mediation cases were handled during the service's 19 months of operation, and some features of the families and the cases are described. Recommendations and directions for future research are included.     

The New Research on Civil Wars: Does It Help Us Understand the Colombian Conflict?

The article synthesizes contributions from the recent comparative research on civil war and the case‐specific literature on Colombia to argue that too often, commentators on this conflict overlook some of its key dimensions. A comprehensive analysis shows that no fewer than six factors are fueling violent conflict in Colombia: economic forces, state weakness, landscape, U.S. policies, long‐duration and spin‐off violence, and malicious opportunism by non‐combatants. The first three are the ones that matter most. The case made here is that when analysts disregard the range and interrelat‐edness of the factors involved, the result is a distortion of reality and a tendency to support policies that will not enhance the prospects for peace.