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Tick vectors and tick‐borne disease are increasingly impacting human populations globally. An important challenge is to understand tick movement patterns, as this information can be used to improve management and predictive modelling of tick population dynamics. Evolutionary analysis of genetic divergence, gene flow and local adaptation provides insight on movement patterns at large spatiotemporal scales. We develop low coverage, whole genome resequencing data for 92 blacklegged ticks, Ixodes scapularis, representing range‐wide variation across the United States. Through analysis of population genomic data, we find that tick populations are structured geographically, with gradual isolation by distance separating three population clusters in the northern United States, southeastern United States and a unique cluster represented by a sample from Tennessee. Populations in the northern United States underwent population contractions during the last glacial period and diverged from southern populations at least 50 thousand years ago. Genome scans of selection provide strong evidence of local adaptation at genes responding to host defences, blood‐feeding and environmental variation. In addition, we explore the potential of low coverage genome sequencing of whole‐tick samples for documenting the diversity of microbial pathogens and recover important tick‐borne pathogens such as Borrelia burgdorferi. The combination of isolation by distance and local adaptation in blacklegged ticks demonstrates that gene flow, including recent expansion, is limited to geographical scales of a few hundred kilometres. [ABSTRACT FROM AUTHOR]

We explore the use of instrumental variables (IV) analysis with a multisite randomized trial to estimate the effect of a mediating variable on an outcome in cases where it can be assumed that the observed mediator is the only mechanism linking treatment assignment to outcomes, an assumption known in the IV literature as the exclusion restriction. We use a random-coefficient IV model that allows both the impact of program assignment on the mediator (compliance with assignment) and the impact of the mediator on the outcome (the mediator effect) to vary across sites and to covary with one another. This extension of conventional fixed-coefficient IV analysis illuminates a potential bias in IV analysis which Reardon and Raudenbush refer to as "compliance-effect covariance bias." We first derive an expression for this bias and then use simulations to investigate the sampling variance of the conventional fixed-coefficient two-stage least squares (2SLS) estimator in the presence of varying (and covarying) compliance and treatment effects. We next develop two alternate IV estimators that are less susceptible to compliance-effect covariance bias. We compare the bias, sampling variance, and root mean squared error of these "bias-corrected IV estimators" to those of 2SLS and ordinary least squares (OLS). We find that, when the first-stage F-statistic exceeds 10 (a commonly used threshold for instrument strength), the bias-corrected estimators typically perform better than 2SLS or OLS. In the last part of the article, we use both the new estimators and 2SLS to reanalyze data from two large multisite studies.

Ozone-sensitive and -tolerant individuals of cutleaf coneflower (Rudbeckia laciniata L.) were compared for their gas exchange characteristics and total non-structural carbohydrates at Purchase Knob, a high elevation site in Great Smoky Mountains National Park, USA. Photosynthesis and stomatal conductance decreased with increased foliar stipple. Sensitive plants had lower photosynthetic rates for all leaves, except the very youngest and oldest when compared to tolerant plants. Stomatal conductance decreased with increasing leaf age, but no ozone-sensitivity differences were found. Lower leaves had less starch than upper ones, while leaves on sensitive plants had less than those on tolerant plants. These results show that ambient levels of ozone in Great Smoky Mountains National Park can adversely affect gas exchange, water use efficiency and leaf starch content in sensitive coneflower plants. Persistence of sensitive genotypes in the Park may be due to physiological recovery in low ozone years. [Copyright &y& Elsevier]

The article examines the efficacy of prestressed concrete piles to support integral abutments and extend the limits on bridge length conducted by the Tennessee Department of Transportation (TDOT) in Tennessee. During the examination, testing of one pile to failure and the cyclic tests performed on one pile were conducted. It is concluded that prestressed concrete piles are appropriate in supporting support integral abutments and the TDOT criteria for bridge lengths are reasonable.

Objectives: A growing body of research has demonstrated the effect of local government spending on health outcomes; however, the effect of spending on different demographic groups is unclear. We combined national and local data to examine the impact of public spending on mortality rates in Tennessee., Methods: Within-between random effects models to examine the relation between county-level spending and mortality rates., Results: We found a significant association between per capita library and kindergarten through grade 12 education spending and mortality outcomes. We also found sex differences in the effects of per capita public health spending and highway spending., Conclusions: This study provides further evidence that local government spending plays a role in addressing and improving population health and suggests that public spending can have differential effects within a population.

Background: Memphis and Shelby County, Tennessee, experienced an epidemic of hepatitis A in 1994 and 1995. More than 1700 cases were reported., Objective: To characterize the clinical features of patients hospitalized during a large urban epidemic of hepatitis A., Design: Retrospective chart review., Setting: 15 acute care hospitals in Shelby County, Tennessee., Patients: 256 patients hospitalized with acute hepatitis A., Measurements: Laboratory findings (such as prothrombin time and bilirubin level), complications, and mortality., Results: The median patient age was 26 years. Thirty-nine complications occurred in 35 patients. Twenty patients (8%) had extrahepatic complications, and 5 (2%) died. Patients 40 years of age and older were more likely to have serious complications, including death (P = 0.014). Sixty-seven patients (26%) presented with coagulopathy (prothrombin time > or = 3 seconds prolonged). Fifty-four patients (21%) had a bilirubin level greater than 170 micromol/L (10 mg/dL)., Conclusions: During this epidemic, hepatitis A caused serious illness and death. Complications were more frequent in patients 40 years of age and older, but young, healthy persons were also at risk for severe complications.