Improved Area of Origin Estimation for Bloodstain Pattern Analysis Using 3D Scanning

An important component of crime scene reconstruction is bloodstain pattern analysis (BPA). Where BPA concerns impact patterns, estimating the area of origin is critical information for scene reconstruction. Traditionally, this is achieved by measuring individual bloodstains and performing trigonometric calculations; however, 3D scanning has been proposed as a viable alternative for overcoming logistical and practical concerns with the manual method. Therefore, this project aimed to establish whether the FARO Focus 3D scanner and FARO Zone 3D software can improve the accuracy of area of origin estimates relative to the manual method. We created a series of eight bloodstain impact patterns and performed paired analysis using the two methods to estimate areas of origin for each pattern. Our data suggested that FARO-derived estimates were generally more accurate than using the manual method. FARO-estimated heights of origin areas were generally closer to the true distance. Both methods underestimated the distance from the wall for most patterns originating 150mm or greater from the wall, but overestimated distances for patterns originating closer to the wall. The degree to which distances were underestimated increased significantly the further the blood source was from the wall and was greater for FARO-derived estimates. The results of this research contribute to the validation of these instruments for operational implementation for BPA and should be considered alongside the practical benefits of 3D scanning relative to manual methods. Further, 3D scanning can provide reliable BPA reconstruction documentation for technical review and court presentation.     

Marijuana medicalization and motor vehicle fatalities: a synthetic control group approach

Journal of Experimental Criminology - This paper reports a quasi-experimental evaluation of California’s 1996 medical marijuana law (MML), known as Proposition 215, on statewide motor vehicle...     

The Role of Intentional Self Regulation,Lower Neighborhood Ecological Assets,and Activity Involvement in Youth Developmental Outcomes

Extracurricular activities provide a key context for youth development, and participation has been linked with positive developmental outcomes. Using data from the 4-H Study of Positive Youth Development (PYD), this study explored how the intentional self regulation ability of youth interacted with participation in extracurricular activities to affect PYD among adolescents living in neighborhoods with relatively low ecological assets. In total, 545 youth were included in the study (50.3% female). Most of the youth were European American (41%) or Latino (37%; African American, 10%; Asian American, 7%; Native American, 4%; and other, 1%). In general, youth with the greatest capacity to self regulate benefitted the most, as compared to their peers with less capacity to self regulate, from involvement in extracurricular activities. Consistent with a developmental systems perspective, and specifically with bioecological theory, the findings from this study confirmed that, within lower asset settings, children with the most positive person-level factors (intentional self regulation) benefit the most from proximal processes such as extracurricular activity involvement.     

Identifying Trajectories of Adolescents’ Depressive Phenomena: An Examination of Early Risk Factors

Few studies have examined risk factors of childhood and early adolescent depressive symptomatology trajectories. This study examined self-report depressive symptomatology across a 6-year time period from 2nd to 8th grade to identify latent groups of individuals with similar patterns of depressive phenomena in a sample of 951 children (440 girls, 511 boys). Analyses, using semiparametric group modeling (SGM), identified 5 trajectory groups for girls and boys: low depressed stables, low depressed risers, mildly depressed stables, moderately depressed changers, and moderately depressed risers. Individual risk factors, with the exception of shy/withdrawn behavior, were significantly different across trajectory group membership for boys and girls, as was low-income status for boys. Boys in the low depressed and mildly depressed stable trajectory groups had significantly higher levels of antisocial behavior, attention problems, and lower social competency compared to girls in similar groups. These results suggest that universal prevention programs implemented in early elementary school that target selected risk factors may be helpful in reducing future adolescent mental health problems, specifically depressive symptomatology.     

The Five Cs Model of Positive Youth Development: A Longitudinal Analysis of Confirmatory Factor Structure and Measurement Invariance

The understanding of positive development across adolescence rests on having a valid and equivalent measure of this construct across the breadth of this period of life. Does the Positive Youth Development (PYD) construct based on the Five Cs model have satisfactory psychometric properties for such longitudinal measurement invariance? Using longitudinal data derived from the 4-H Study of PYD, we assessed 920 youth (61.6% female) from a racially and ethically diverse sample (67.3% European American) who participated in three waves (Grades 8–10) of data collection. Building on prior findings that the Five Cs (i.e., Competence, Confidence, Connection, Character, and Caring) model of PYD was a robust measure that could be assessed comparably during early adolescence, we tested a hierarchy of second-order confirmatory factor analysis models to assess the extent to which PYD can be measured equivalently across middle adolescence. Evidence was found for strict measurement invariance across three measurement occasions, including equivalence of first-order and second-order factor loadings, equality of intercepts of observed variables, and equality of item uniqueness and disturbances of the first-order factors. These results suggest that PYD can be measured in the same way across measurement occasions, a prerequisite for the study of development. Implications for research and application of being able to measure PYD equivalently across adolescence are discussed.     

Intentional Self Regulation in Middle Adolescence: The Emerging Role of Loss-based Selection in Positive Youth Development

Intentional self regulation describes how people make choices, plan actions to reach their goals, and regulate the execution of their actions, making processes of intentional self regulation central to healthy human functioning. Prior research has confirmed the presence of three processes of intentional self regulation—elective selection (ES), optimization (O), and compensation (C)—in middle adolescence (Grades 8 through 10) and concurrent and predictive relationships with measures of Positive Youth Development (PYD). A fourth process, loss-based selection (LBS), should also develop by the end of middle adolescence. The present study used data from the 4-H Study of PYD to confirm the presence of a four-scale structure of intentional self regulation (ES, O, C, and LBS) in a sample of 2,357 racially diverse Grade 10 youth (63% female) and examine its covariation with indicators of positive and problematic development. Results supported the identification of a four-part structure of intentional self regulation, and scores covaried positively with indicators of PYD and negatively with substance use, delinquency, and depressive symptoms. Implications of the findings for the understanding of self-regulatory actions in adolescence and for future research are discussed.     

Local Institutions and the Politics of Urban Growth

This article uses a political market framework to analyze how the structure of local political institutions affects the relative political influence of development and environmental interests in the context of urban growth. Using panel data from 406 Florida cities from 1998 to 2003, the empirical analysis finds important interaction effects between the structure of city executive branch institutions and interest group variables. The economic and political forces driving urban growth do not operate identically in all cities—they vary as a function of institutional context. Institutional structure helps determine which interest groups have their preferences reflected in local land-use changes and development patterns. The resulting patterns suggest a "sustainability paradox" wherein richer, environmental interests push for the preservation of environmental amenities while at the same time accelerating the number of residential units built in a community.     

The impact of surplus sharing on the portfolio mix of public sector defined benefit pension plans: a public choice approach

The riskiness of state employee pension plan portfolios varies across states. We investigate whether this variation is related to how public employees and taxpayers share actuarial surpluses of pension accounts. We focus on two determinants of a plan’s asset mix: the relative influence of public employees to taxpayers; and whether a surplus-sharing contract is specified. Our theoretical model demonstrates that the effect of public employee influence on the asset mix is ambiguous. Our empirical results corroborate this complex theoretical result. In our theoretical and empirical analyses, if a surplus sharing rule is specified, plans adopt a more aggressive investment allocation.