DNA Analysis of Natural Fiber Rope*

Abstract: When rope is found at a crime scene, the type of fiber is currently identified through its microscopic characteristics. However, these characteristics may not always unambiguously distinguish some types of rope from others. If rope samples contain cells from the plants of origin, then DNA analysis may prove to be a better way to identify the type of rope obtained from a crime scene. The objective of this project was to develop techniques of DNA analysis that can be used to differentiate between ropes made from Cannabis sativa L. (hemp), Agave sisalana Perrine (sisal), Musa textilis Née (abaca, “Manila hemp”), Linum usitatissimum L. (flax), and Corchorus olitorus L. (jute). The procedures included extracting the DNA from the rope, performing polymerase chain reaction (PCR) using the extracted DNA as a template, and analyzing the DNA products. A primer pair for PCR, chosen from within a chloroplast gene for the large subunit of ribulose bisphosphate carboxylase/oxygenase, was designed to be specific for plant DNA and complementary to the genes from all five plants. The resulting PCR fragments were approximately 771 base pairs long. The PCR fragments, distinguished through base sequence analysis or restriction enzyme analysis, could be used to identify the five different rope types. The procedure provides a useful addition to visual methods of comparing rope samples.     

Mickey Mouse numbers and inequality research in developing countries

The usage of unreliable statistics is common in development economics, particularly in research on income distributional issues. It is widely believed, for example, that the distribution of income in Taiwan equalised dramatically between the early 1950s and about 1980. Under close examination it is clear much of the evidence advanced is flawed, the treatment of data by a number of analysts is puzzling, and links between export‐orientation and inequality trends are flimsy. It is argued that economists should be far more concerned about data problems in their research.     

Intergenerational continuities and discontinuities in intimate partner violence: a two-generational prospective study

This study focuses on intergenerational continuity in violent partner relationships. We investigate whether exposure to caregiver intimate partner violence (IPV) during adolescence leads to increased involvement in IPV during early adulthood (age 21-23) and adulthood (age 29-31). We also investigate whether this relationship differs by gender. Although there is theoretical and empirical support for intergenerational continuity of relationship violence, there are few prospective studies of this issue. We use data from the Rochester Youth Development Study (RYDS), a longitudinal study of the development of antisocial behavior in a community sample of 1,000 urban youth followed from age 14 to adulthood. The original sample includes 73% men and 85% African American or Hispanic youth. Measures come from a combination of interviews and official records. The Conflict Tactics Scale (CTS) is used to assess IPV and severe IPV in the youth and parent generations. Analyses controlled for child physical abuse, race/ethnicity as well as parent education, family stability, and poverty. In multivariate models, adolescent exposure to caregiver severe IPV resulted in significantly increased risk of relationship violence in early adulthood (age 21-23). Furthermore, there is an indirect effect of adolescent exposure to severe IPV on later adult involvement in IPV (age 29-31), mediated by involvement in a violent relationship in early adulthood. These results were largely invariant by gender. However, we observed a direct pathway between IPV exposure and adult IPV for women (marginally significant) suggesting that adolescent exposure to caregiver IPV may set in motion women-specific processes.     

Can Situational and Structural Factors Differentiate Between Intimate Partner and “Other” Homicide?

A large body of research has identified strong and consistent correlates of aggregated intimate homicide incidents; however, the bulk of these studies focuses on the influence of either case or neighborhood characteristics on homicide types, but not both. This study examines data collected from 739 homicides in two distinct metropolitan cities to determine which factors differentiate intimate and non-intimate homicide. Findings reveal that intimate partner homicides (IPH) are more likely to involve females both as victims and offenders when compared to non-IPH incidents. In addition, IPH homicides are more likely to be committed with weapons than non-IPH, but this finding only appears in Indianapolis homicides. Indeed, one of the stark contrasts between Indianapolis and Newark was the much greater prevalence of firearms involved in IPH homicides in Indianapolis. This suggests the need for future research that sorts out patterns of household gun possession, factors influencing community levels of household gun possession, and the use of legally- or illegally-possessed firearms in IPH homicide.     

Evaluation of pediatric skull fracture imaging techniques

Radiologic imaging is crucial in the diagnosis of skull fracture, but there is some doubt as to whether different imaging modalities can accurately identify fractures present on a human skull. While studies have been performed to evaluate the efficacy of radiologic imaging at other anatomical locations, there have been no systematic studies comparing various CT techniques, including high resolution imaging with and without 3D reconstructions to conventional radiologic imaging in children, we investigated which imaging modalities: high-resolution CT scan with 3D projections, clinical-resolution CT scans or X-rays, best showed fracture occurrence in a pediatric human cadaver skull by having an expert pediatric radiologist examine radiologic images from fractured skulls. The skulls used were taken from pediatric cadavers ranging in age from 5 months to 16 years. We evaluated the sensitivity and specificity for the imaging modalities using dissection findings as the gold standard. We found that high-resolution CT scans with 3D projections and conventional CT provided the most accurate fracture diagnosis (single-fracture sensitivity of 71%) followed by X-rays (single-fracture sensitivity of 63%). Linear fractures outsider the region of the sutures were more identifiable than diastatic fractures, though the incidence of false positives was greater for linear fractures. In the two cases where multiple fractures were present on the same anatomical skull location, the radiologist was less likely to identify the presence of additional fractures than a single fracture. Overall, the high-resolution and clinical-resolution CT scans had the similar accuracy for detecting skull fractures while the use of the X-ray was both less accurate and had a lower specificity.     

Overview of: “The Impact of Drug Market Pulling Levers Policing on Neighborhood Violence: An Evaluation of the High Point Drug Market Intervention”

Research Summary Pulling levers policing draws upon the focused deterrence framework, which has shown considerable promise when directed at youth, gun, and gang offenders. However, much less is known about the viability of pulling levers when applied to different contexts as well as to diverse groups of offenders. We examine the High Point (North Carolina) Drug Market Intervention (DMI), the first site to use pulling levers as a place-based policing approach to disrupt a series of open-air drug markets across the city. Eleven years of longitudinal data are analyzed by using difference-in-difference panel regression analyses combined with finite mixture estimation as a means to test for divergence in violent crime patterns. Several key, although inconsistent, findings are presented. First, we found a statistically significant reduction in violent offenses in specific high-crime places (i.e., high-trajectory census blocks) located across the different targeted neighborhoods compared with the remainder of High Point, and relative to comparable nontargeted areas. Second, the citywide violent crime rate actually increased after a series of interventions unfolded, which may suggest limitations with the approach. Finally, trend analyses indicated the strategy had different levels of violent crime impact throughout unique geographic contexts. Policy Implications Rather than arresting every offender identified as having participated in illicit drug trafficking across various geographic contexts within the city, officials in High Point decided to invite low-risk drug offenders to community notification sessions in order to change their perceived risk of punishment as well as to mobilize community members across the different targeted neighborhoods. The suggestive evidence of potential, although limited, violent crime impact illustrates that this type of policing strategy may hold considerable promise. This interpretation gains credence when considered with prior evaluations of the DMI approach that illustrated the potential for reducing drug-related crime and in light of reports of improved police–community relations. The inconsistent findings across all locations and the overall city increase in violent crime toward the end of the study period, however, raise several concerns when interpreting study results. Additionally, our findings suggest that further replications should include systematic problem-identification, process measures, and more precise research designs.