Computer program for calculating laminar, transitional, and turbulent boundary layers for a compressible axisymmetric flow

Finite-difference computer program calculates viscous compressible boundary layer flow over either planar or axisymmetric surfaces. Flow may be initially laminar and progress through transitional zone to fully turbulent flow, or it may remain laminar, depending on imposed boundary conditions, laws of viscosity, and numerical solution of momentum and energy equations

Spatial Endogenous Fire Risk and Efficient Fuel Management and Timber Harvest

This paper integrates a spatial fire behavior model and a stochastic dynamic optimization model to determine the optimal spatial pattern of fuel management and timber harvest. Each years fire season causes the loss of forest values and lives in the western US. This paper uses a multi-plot analysis and incorporates uncertainty about fire ignition locations and weather conditions to inform policy by examining the role of spatial endogenous risk - where management actions on one stand affect fire risk in that and adjacent stands. The results support two current strategies, but question two other strategies, for managing forests with fire risk.Resource /Energy Economics and Policy,

Identifying and mitigating biases in EHR laboratory tests

AbstractElectronic health record (EHR) data show promise for deriving new ways of modeling human disease states. Although EHR researchers often use numerical values of laboratory tests as features in disease models, a great deal of information is contained in the context within which a laboratory test is taken. For example, the same numerical value of a creatinine test has different interpretation for a chronic kidney disease patient and a patient with acute kidney injury. We study whether EHR research studies are subject to biased results and interpretations if laboratory measurements taken in different contexts are not explicitly separated. We show that the context of a laboratory test measurement can often be captured by the way the test is measured through time.We perform three tasks to study the properties of these temporal measurement patterns. In the first task, we confirm that laboratory test measurement patterns provide additional information to the stand-alone numerical value. The second task identifies three measurement pattern motifs across a set of 70 laboratory tests performed for over 14,000 patients. Of these, one motif exhibits properties that can lead to biased research results. In the third task, we demonstrate the potential for biased results on a specific example. We conduct an association study of lipase test values to acute pancreatitis. We observe a diluted signal when using only a lipase value threshold, whereas the full association is recovered when properly accounting for lipase measurements in different contexts (leveraging the lipase measurement patterns to separate the contexts).Aggregating EHR data without separating distinct laboratory test measurement patterns can intermix patients with different diseases, leading to the confounding of signals in large-scale EHR analyses. This paper presents a methodology for leveraging measurement frequency to identify and reduce laboratory test biases

Natality of Yearling Coyotes in West Virginia

Minimal information is available regarding the reproduction of coyotes (Canis latrans) in the Mid-Atlantic region, which includes the states of Delaware, Maryland, North Carolina, Pennsylvania, Virginia, and West Virginia. Since reproductive information is useful to assess populations and determine management strategies and because this information is unavailable for the Mid-Atlantic, we examined uterine tracts of 66 female coyotes collected from February to May 2010 for fetuses. We measured fetuses using a digital caliper and approximated dates of conception and parturition. Nine (13.6%) female coyotes were pregnant with visible fetuses; seven of these females were yearlings (1.5–2.5 y old). Average litter size of yearling coyotes was 5.4 (SE=0.48). We estimated an average conception date of 2 February and an average parturition date of 6 April. Conception and parturition dates were within the reported range for coyotes, though one female successfully bred in early January, which is earlier than reported in the literature. The relatively high proportion (30.4%) of yearling females breeding in West Virginia may reflect abundant food resources, low density of coyotes, increasing human-caused mortality, or a combination of these factors. Reproductive information reported here will be helpful in monitoring coyote population trends and in the assessment of management strategies

Natality of Yearling Coyotes in West Virginia

Minimal information is available regarding the reproduction of coyotes (Canis latrans) in the Mid-Atlantic region, which includes the states of Delaware, Maryland, North Carolina, Pennsylvania, Virginia, and West Virginia. Since reproductive information is useful to assess populations and determine management strategies and because this information is unavailable for the Mid-Atlantic, we examined uterine tracts of 66 female coyotes collected from February to May 2010 for fetuses. We measured fetuses using a digital caliper and approximated dates of conception and parturition. Nine (13.6%) female coyotes were pregnant with visible fetuses; seven of these females were yearlings (1.5–2.5 y old). Average litter size of yearling coyotes was 5.4 (SE=0.48). We estimated an average conception date of 2 February and an average parturition date of 6 April. Conception and parturition dates were within the reported range for coyotes, though one female successfully bred in early January, which is earlier than reported in the literature. The relatively high proportion (30.4%) of yearling females breeding in West Virginia may reflect abundant food resources, low density of coyotes, increasing human-caused mortality, or a combination of these factors. Reproductive information reported here will be helpful in monitoring coyote population trends and in the assessment of management strategies

High-speed Civil Transport Aircraft Emissions

Estimates are given for the emissions from a proposed high speed civil transport (HSCT). This advanced technology supersonic aircraft would fly in the lower stratosphere at a speed of roughly Mach 1.6 to 3.2 (470 to 950 m/sec or 920 to 1850 knots). Because it would fly in the stratosphere at an altitude in the range of 15 to 23 km commensurate with its design speed, its exhaust effluents could perturb the chemical balance in the upper atmosphere. The first step in determining the nature and magnitude of any chemical changes in the atmosphere resulting from these proposed aircraft is to identify and quantify the chemically important species they emit. Relevant earlier work is summarized, dating back to the Climatic Impact Assessment Program of the early 1970s and current propulsion research efforts. Estimates are provided of the chemical composition of an HSCT's exhaust, and these emission indices are presented. Other aircraft emissions that are not due to combustion processes are also summarized; these emissions are found to be much smaller than the exhaust emissions. Future advances in propulsion technology, in experimental measurement techniques, and in understanding upper atmospheric chemistry may affect these estimates of the amounts of trace exhaust species or their relative importance