The feasibility of external blind DNA proficiency testing. I. Background and findings

We describe the origins, purposes, and findings of a national study to determine whether a large-scale program of blind proficiency testing in U.S. DNA laboratories is feasible and/or practical. Proficiency testing in clinical laboratories is reviewed, particularly as mandated by the Clinical Laboratory Improvement Acts and its role in the regulation of those laboratories. Proficiency testing in forensic urine drug testing labs is also briefly reviewed. Studies involving comparisons between open and blind proficiency testing are discussed. The clinical laboratory proficiency testing and regulation landscape provides the background for the DNA Act of 1994, and the congressional mandate to investigate blind proficiency testing in forensic DNA laboratories. Four models of blind proficiency testing are defined and discussed, along with the advantages and disadvantages of each and estimates of the costs of a large-scale program. The purposes of proficiency testing in a quality-assurance context are likewise discussed and related to the models and the arguments generally proffered for and against blind vs. open proficiency testing.     

Partisan Gaps in Political Information and Information‐Seeking Behavior: Motivated Reasoning or Cheerleading?

Do partisan disagreements over politically relevant facts, and preferences for the information sources from which to obtain them, represent genuine differences of opinion or insincere cheerleading? The answer to this question is crucial for understanding the scope of partisan polarization. We test between these alternatives with experiments that offer incentives for correct survey responses and allow respondents to search for information before answering each question. We find that partisan cheerleading inflates divides in factual information, but only modestly. Incentives have no impact on partisan divides in information search; these divides are no different from those that occur outside the survey context when we examine web‐browsing data from the same respondents. Overall, our findings support the motivated reasoning interpretation of misinformation; partisans seek out information with congenial slant and sincerely adopt inaccurate beliefs that cast their party in a favorable light.     

Against the Grain of Urban Bias: Elite Conflict and the Logic of Coalition Formation in Colonial and Post-Colonial Africa

The theory of urban bias was a major contribution to the evolution of contemporary theories of political economy that remains highly relevant today. Yet theorists of urban bias have still not produced a general explanation that accounts for anomalous cases of what we call “rural incorporation,” or coalition strategies based on modest rural producers. These anomalous cases suggest that the collective action underpinnings of urban bias theory underdetermine outcomes. This paper advances a new explanation of the anomalous African cases of Kenya, Côte d’Ivoire, and Zimbabwe. After detailing the costs of rural incorporation, we theorize the conditions that would motivate state elites to overcome their pro-urban biases and offer substantial material benefits to non-elite agrarian producers. Rural incorporation is an optimal strategy only when state elites are locked in unusually intense conflict with their rivals. Most nationalist movements in Africa did not meet this condition and their leaders followed pro-urban policies. The three outliers are all cases of settler colonialism: bitter rivalry between European settlers and native planters created the conditions for rural incorporation. We show how native planters and their political allies selected rural incorporation as a political-economic instrument of commercial competition and political supremacy. Case studies of Ghana and Nigeria demonstrate that in the absence of political and economic rivalry with settlers, African leaders selected the “default” strategy of urban bias.     

Estimating postmortem interval for human cadavers in a sub‐tropical climate using UV‐Vis‐near‐infrared Spectroscopy

Estimating postmortem interval (PMI) of surface found skeletal remains is challenging. This novel study used UV‐Vis‐NIR spectroscopy to scan soil collected from cadaver decomposition islands (CDIs) ranging from 15‐ to 963‐d postmortem and control soils. A decomposition product spectra model (DPS model) was constructed by deducting the control soil spectra from the CDI soil spectra for the estimation of postmortem indices: PMI (d), ADD₄, ADD₁₀, and ADD₂₀. The DPS model (n = 55) was calibrated and subjected to a full cross‐validation. Calibration R² and RPD for the DPS model ranged from 0.97 to 0.99 and from 6.1 to 9.9, respectively, for the four postmortem interval indices. Validation R² and RPD for the DPS model ranged from 0.73 to 0.80 and from 1.9 to 2.2, respectively. The DPS model estimated postmortem intervals for three test CDIs in a clay soil under perennial grassland (test set 1; n = 3) and six CDIs in a sandy soil under a loblolly pine forest (test set 2; n = 6). Test set 1 had PMI prediction ranges from ?69 to ?117 days, ?796 to +832 ADD₄, +552 to +2672 ADD₁₀, and ?478 to ?20 ADD₂₀ of observed PMI. Test set 2 PMI prediction ranged from ?198 to ?65 days, ?9923 to +2629 ADD₄, ?6724 to +1321 ADD₁₀, and ?2850 to +540 ADD₂₀ of observed PMI. Test set 2 had poor predictions for two CDIs, for all measures of postmortem indices resulting in discussion of sampling depth, effect of body mass index (BMI), and scavenging.