Quantification and aging of the post-blast residue of TNT landmines

Post-blast residues are potential interferents to chemical detection of landmines. To assess the potential problem related to 2,4,6-trinitrotoluene (TNT), its post-blast residue was identified and quantified. In the first part of this study laboratory-scale samples of TNT (2 g) were detonated in a small-scale explosivity device (SSED) to evaluate the explosive power and collect post-blast residue for chemical analysis. Initiator size was large relative to the TNT charge; thus, issues arose regarding choice of initiator, residue from the initiator, and afterburning of TNT. The second part of this study detonated 75 to 150 g of military-grade TNT (typical of antipersonnel mines) in 55-gal barrels containing various witness materials (metal plates, sand, barrel walls, the atmosphere). The witness materials were analyzed for explosive residue. In a third set of tests, 75-g samples of TNT were detonated over soil (from Fort Leonard Wood or Sandia National Laboratory) in an indoor firing chamber (100 by 4.6 by 2.7 m high). Targeted in these studies were TNT and four explosive-related compounds (ERC): 2,4-dinitrotoluene (DNT), 1,3-dinitrobenzene (DNB), 2- and 4-aminodinitrotoluene (2-ADNT and 4-ADNT). The latter two are microbial degradation products of TNT. Post-blast residue was allowed to age in the soils as a function of moisture contents (5 and 10%) in order to quantify the rate of degradation of the principal residues (TNT, DNT, and DNB) and formation of the TNT microbial degradation products (2-ADNT and 4-ADNT). The major distinction between landmine leakage and post-blast residue was not the identity of the species but relative ratios of amounts. In landmine leakage the DNT/TNT ratio was usually greater than 1. In post-blast residue it was on the order of 1 to 1/100th of a percent, and the total amount of pre-blast residue (landmine leakage) was a factor of 1/100 to 1/1000 less than post-blast. In addition, landmine leakage resulted in low DNT/ADNT ratios, usually less than 1, whereas pre-blast residues started with ratios above 20. Because with time DNT decreased and ADNT increased, over a month the ratio decreased by a factor of 2. The rate of TNT degradation in soil observed in this study was much slower than that reported when initial concentrations of TNT were lower. Degradation rates yielded half-lives of 40 and 100 days for 2,4-DNT and TNT, respectively.     

R&D consortia: Impact on competitiveness?

This research examines the impact of research and development (R&D) consortia on the competitiveness of American companies. It also concludes that since passage of the 1984 National Collaborative Research Act, which allows companies to jointly perform research, only a few R&D consortia have been formed and they do not have much impact on companies through applications of new technology. It is suggested that R&D consortia may have more impact on firms that are catching-up technologically or for which the particular research is tangential to their core business. He holds a Ph.D. in public policy from the George Washington University (1988), and has worked for the National Science Foundation, the Congressional Office of Technology Assessment, and the National Academy of Sciences. His interests focus on technology, economic competitiveness, and government policy. He has recently published on these topics in Research Policy (August 1990), and Policy Studies Review (Spring 1991, forthcoming).     

Most Significant Change in conflict settings: staff development through monitoring and evaluation

Capoeira4Refugees is an NGO that uses the Afro-Brazilian art form of Capoeira to promote psychosocial well-being in children affected by conflict and occupation. Capoeira4Refugees introduced the Most Significant Change (MSC) methodology to monitor and evaluate project implementation and impact across two locations in the Middle East. Analysis of interviews conducted with five field staff revealed that in line with, and building on, previous research, MSC became an empowering tool that led to staff development. The potential for MSC to build staff reflexivity, independence, and leadership has implications for other organisations working in conflict areas, particularly in situations of remote management.     

The Profession of Public Administration: An Ethics Edge in Introductory Textbooks?

Given the substantial interest in public service ethics, this study examines its foundations as reflected in paradigmatic textbooks—a unit of analysis that informs both theory and practice in the field. The interpretative framework employed evaluates the context (the amount and placement of the topic, the use of graphics, and sources cited) as well as the content (conceptualization of management ethics and inclusion of implementation issues) of ethics found in the publications. A limited definition of a professional—one in possession of largely technical skills—is reflected in the textbooks. The implications of the findings are explored.     

Contagious COVID-19 policies: Policy diffusion during times of crisis

The COVID-19 crisis demanded rapid, widespread policy action. In response, nations turned to different forms of social distancing policies to reduce the spread of the virus. These policies were implemented globally, proving as contagious as the virus they are meant to prevent. Yet, variation in their implementation invites questions as to how and why countries adopt social distancing policies, and whether the causal mechanisms driving these policy adoptions are based on internal resources and problem conditions or other external factors such as conditions in other countries. We leverage daily changes in international social distancing policies to understand the impacts of problem characteristics, institutional and economic context, and peer effects on social distancing policy adoption. Using fixed-effects models on an international panel of daily data from 2020, we find that peer effects, particularly mimicry of geographic neighbors, political peers, and language agnates drive policy diffusion and shape countries' policy choices.     

Teacher Skill Development: Evidence from Performance Ratings by Principals

We examine the dynamic nature of teacher skill development using panel data on principals’ subjective performance ratings of teachers. Past research on teacher productivity improvement has focused primarily on one important but narrow measure of performance: teachers’ value-added to student achievement on standardized tests. Unlike value-added, subjective performance ratings provide detailed information about specific skill dimensions and are available for teachers in non-tested grades and subjects. Using a within-teacher returns-to-experience framework, we find, on average, large and rapid improvements in teachers’ instructional practices throughout their first 10 years on the job as well as substantial differences in improvement rates across individual teachers. We also document that subjective performance ratings contain important information about teacher effectiveness. In the district we study, principals appear to differentiate teacher performance throughout the full distribution instead of just in the tails. Furthermore, prior performance ratings and gains in these ratings provide additional information about teachers’ ability to improve test scores that is not captured by prior value-added scores. Taken together, our study provides new insights on teacher performance improvement and variation in teacher development across instructional skills and individual teachers.     

Deficits in Emotional Clarity and Vulnerability to Peer Victimization and Internalizing Symptoms Among Early Adolescents

Peer victimization is a significant risk factor for a range of negative outcomes during adolescence, including depression and anxiety. Recent research has evaluated individual characteristics that heighten the risk of experiencing peer victimization. However, the role of emotional clarity, or the ability to understand one’s emotions, in being the target of peer victimization remains unclear. Thus, the present study evaluated whether deficits in emotional clarity increased the risk of experiencing peer victimization, particularly among adolescent girls, which, in turn, contributed to prospective levels of depressive and anxiety symptoms. In the present study, 355 early adolescents (ages 12–13; 53 % female; 51 % African American) who were part of the Adolescent Cognition and Emotion project completed measures of emotional clarity, depressive symptoms, and anxiety symptoms at baseline, and measures of peer victimization, depressive symptoms, and anxiety symptoms at follow-up. Moderation analyses indicated that deficits in emotional clarity predicted greater peer victimization among adolescent girls, but not adolescent boys. Moderated mediation analyses revealed that deficits in emotional clarity contributed to relational peer victimization, which, in turn, predicted prospective levels of depressive and anxiety symptoms among adolescent girls, but not boys. These findings indicate that deficits in emotional clarity represent a significant risk factor for adolescent girls to experience relational peer victimization, which, in turn, contributed to prospective levels of internalizing symptoms. Thus, prevention programs should target deficits in emotional clarity to prevent peer victimization and subsequent internalizing symptoms among adolescent girls.     

An introduction to judicial fact-finding

This article seeks to provide an introduction as to how judges determine facts. It draws on material across a range of jurisdictions as to how judges themselves have described what they do and what they ought to do. It explores what factors judges take into account when deciding whether the evidence of a witness is credible. It examines the difference between recollection and reconstruction of events by witnesses and considers how judges draw inferences from primary facts. The importance of documentary evidence, expert evidence, judicial notice and the giving of reasons in the fact-finding process are also explored.