Weights and morphometrics of black bears in the southeastern United States

Weights and body size measurements (morphometrics) of mammals may vary throughout the range of a species for different reasons. Populations may vary genetically, demographically, or nutritionally, any 1 of which (or combination thereof) could alter the weights and morphometrics of its constituents. The objectives of my study were to determine if black bear (Ursus americanus) populations vary in weights and morphometrics and, if so, to determine if these differences correspond to current subspecies demarcations or, alternatively, to regional habitat quality indices. I also determined the level of variation introduced into morphometric data when multiple researchers collect field data. I compared the summer weights and morphometrics of 260 adult black bears, collected from 20 locations throughout the Southeast and selected other areas in the United States from 1992 to 1994. I estimated missing data points using multiple regression analyses and combined the sexes using sexual dimorphism correction factors. I partitioned the 20 populations based on 1) traditional subspecies demarcations of black bears and 2) Bailey\u27s (1980) ecoregion province delineations. Then, I determined the optimal clusterings of these partition schemes using the minimum of Akaike\u27s information criterion (AIC) and information complexity based on the inverse-Fisher information matrix (ICOMPIFIM) in multi-sample cluster analyses. Black bears in both the subspecies and ecoregion province partition schemes grouped separately based on their weights and morphometrics in the multi-sample cluster analyses. Therefore, there was evidence supporting the subspecies demarcations, but there was also evidence that this classification may not account for all of the morphometric variation found in black bears in the eastern United States. I concluded that U. a. americanus, U. a. luteolus and U. a. floridanus were morphometrically distinct subspecies, but that there may be additional morphometric differences within the range of U. a. americanus The weight and morphometric differences indicated by the multi-sample cluster analyses, however, were not correlated with regional habitat quality indices as measured by: crop yields, latitude, actual evapotranspiration, and soil fertility. Additionally, in Great Smoky Mountains National Park (TN) and Neuse-Pamlico Peninsula (NC), black bears exhibited inter-year differences in weights and morphometrics. Therefore, I hypothesized that black bears may respond temporally to habitat quality at a sub-regional level. I estimated the variation in morphometrics of black bears (Ursus americanus) taken by 6 field researchers. Eight body measurements were recorded by 3 teams of 2 researchers on a total of 70 black bears in Great Smoky Mountains National Park in Tennessee and North Carolina. Measurements were summarized to determine the intra- and inter-researcher variation present in the morphometrics. I then ran simulations on predictive equations to determine how the observed variation affected the results. The intra-researcher simulations differed from one another by 1.5 - 2 .6% of the average of the predicted parameters and the inter-researcher simulations differed fi om one another by 3.4 - 8.1% of the average of the predicted parameters. These differences may explain some of the error associated with analyses and predictive equations based on morphometrics. Consequently, it is imperative for researchers to minimize the error of taking measurements by developing stringent standards for data collection and by reducing the number of personnel involved in data collection

Ultrasonic thickness structural health monitoring of steel pipe for internal corrosion

The naphthenic acid corrosion that can occur in oil refinery process plants at high temperature (400ÃÂðC) due to the corrosive nature of certain crude oils during the refining process can be difficult to predict. Therefore, the development of online ultrasonic thickness (UT) structural health monitoring (SHM) technology for high temperature internal pitting corrosion of steel pipe is of interest. A sensor produced by the sol-gel ceramic fabrication process has the potential to be deployed to monitor such pitting corrosion, and to help investigate the mechanisms causing such corrosion. This thick-film transducer is first characterized using an electric circuit model. The propagating elastic waves generated by the transducer are then experimentally characterized using the dynamic photoelastic visualization method and images of the wave-field are compared with semi-analytical modeling results. Next, the classic elastic wave scattering theory for an embedded spherical cavity is reviewed, results are compared with a newer scattering theory from the seismology community, that has been applied to a hemispherical pit geometry. This hemispherical pit theory is extended so as to describe ultrasonic Non-Destructive Evaluation (NDE) applications, for pitting corrosion, with the derivation of a far-field scattering amplitude term. Data from this new scattering theory is compared with experimental results by applying principals from the Thompson-Gray measurement model. The initial model validation provides the basis for a possible new hemispherical pit geometric reference standard for ultrasonic NDE corrosion applications. Next, UT SHM measurement accuracy, precision, and reliability are described with a new weighted censored relative likelihood methodology to consider the propagation of asymmetric uncertainty in quantifying thickness measurement error. This new statistical method is experimentally demonstrated and applied to thickness measurement data obtained in pulse-echo and pitch-catch configurations for various time-of-flight thickness calculation methods. Finally, the plastic behavior of a corroded steel pipe is modeled with analytical and finite element methods to generate prognosis information

Econometric Evidence Regarding Education and Border Income Performance

This study examines the relationship between education and income in Texas counties that are located along the border with Mexico. Estimation results confirm ealrier research results for this region. Parameter heterogeneity underscores the increased importance of education in the service-oriented labor market that has emerged in recent years in the United States. Simulation results quantify the income gains that could potentially be realized if drop out rates were lowered in the border counties included in the sample.Education; Texas border incomes; applied econometrics

Ultrasonic Scattering from a Hemispherical Pit Theory and Experimental Measurement Precision

The accuracy and precision of ultrasonic thickness measurement systems are influenced by systematic and environmental factors including the back-wall reflection surface profile. The scattering amplitude from a relatively flat and smooth back-wall surface can be characterized by the acoustic impedance ratio of the two materials at the interface. If the back-wall surface increases in roughness due to internal corrosion, then the arrival time of the incident wave upon the various surface heights will be slightly different, resulting in slight phase changes within the reflected field. In addition, the roughness of the internal surface will result in various impingement anglesrelative to the incident wave causing some mode conversion. The reflected wave field is composed of the coherent field (same phase and same relative angle as the incident wave) and the diffuse field (random phase and random angle). As roughness increases, more energy is converted to the diffuse field resulting in a decrease in the reflected coherent field. This reduction in energy from the coherent field can be observed with a transducer by a decrease in voltage amplitude as well as a change in the frequency component of the received signal. A single corrosive pit can be represented as a hemisphere in a half-space to model the initiation point of rough surface corrosion, or to model isolated pitting degradation as possible with naphthenic acid corrosion in oil refineries. The case of a single hemispherical pit with a normal incident compression wave has been studied in NDE applications and in the seismology community with a recent presentation of a full analytical solution. This paper looks to present the thickness measurement accuracy and precision of various time-of-flight thick- ness calculation methods taking into consideration asymmetric measurement uncertainty for the case of a normal incident compression wave on both a relatively smooth back-wall surface and on a hemispherical pit. In addition, this paper looks to compare a full analytical solution, various scattering approximations (such as Kirchoff), as well as experimental measurements presented as scattering coefficients relative to normalized frequency for the case of a hemispherical pit

Ultrasonic Sol-Gel Arrays for Monitoring High-Temperature Corrosion

Corrosion of oil refinery equipment operating at high temperature is a growing challenge linked to an increase in sulfur concentration and acidity within the world supply of crude oils. Improved high temperature monitoring tools are needed to continuously measure the local minimum wall thickness of steel pipe subject to non-uniform internal corrosion. Thickness measurements must be sufficiently accurate to calculate the maximum allowable stress permissible as to avoid failure. Thickness measurements must also be sufficiently reliable and precise to correlate the rate of wall-loss with process conditions as to improve future corrosion rate predictions. Permanently installed structural health monitoring (SHM) technologies have the potential to meet these needs and an ultrasonic sensor technology based on the sol-gel ceramic fabrication process will be presented. The sol-gel thin-film sensor fabrication process is described: aerosol printing of high-temperature piezoceramic material, heat curing, polarization, electrode deposition, and wiring. The sensors are characterized with the photoelastic visualization method by first, recording the propagating elastic waves as a sequence of images, then, processing the image frames to reconstruct a beam profile through identification of the maximum optical intensity for each pixel via normalizing, filtering, and smoothing. A sol-gel transducer is shown to be similar to a traditional manual contact transducer. The systematic and environmental factors that impact ultrasonic thickness measurement accuracy, precision, and reliability are discussed. An experiment is conducted using a flat-bottom-hole calibration pipe at ambient temperature with sol-gel transducer arrays in pulse-echo and pitch-catch configuration for various time-of-flight thickness calculation methods. A weighted censored relative maximum likelihood statistical method incorporating the propagation of asymmetric uncertainty is used to report thickness measurement results with confidence limits analogous to the a90/95 terminology used in Probability-of-Detection (POD) assessments. Future work is discussed to apply the statistical analysis technique to complex back-wall surfaces at high temperature representative of naphthenic acid corrosion in oil refineries

Collegiate Athletic Trainers’ Experiences Planning for Return-to-Sports During COVID-19: A Qualitative Research Study

Purpose: The purpose of this study was to explore the role of intercollegiate head athletic trainers in the process of planning to resume sport, as well as their experiences across the course of the pandemic to identify key strategies, challenges, and future considerations during the Covid-19 pandemic. Method: This exploratory, descriptive qualitative study was conducted via one-on-one semi structured interviews through the Zoom video conference technology. Twenty-four head athletic trainers across NCAA Division I, II, and III institutions participated in the study. Results: Emerging themes included the development of detailed, institution-specific plans with shared elements such as policies for testing and screening, modifications to facilities and cleaning, and incorporation of coach and athlete education. Athletic trainers discussed the processes they used to create their return-to-sport policies, which included professional development and interprofessional collaborations. While participants were confident in their plans, they acknowledged the need to overcome logistical and psychosocial challenges, such as the recognition that the success of their plans relied on numerous variables that could not be completely controlled. Conclusion: It is clear that NCAA ATs have played – and will continue to play – an integral role in overcoming challenges to promote a safe return-to-sports amidst the COVID-19 pandemic via education, policy making, and delivery of healthcare services. The challenges imposed by the accompanying set of circumstances have strained these ATs’ practical tendencies and procedures. ATs have met these challenges through collaboration, information-seeking, and acceptance of the situation. NCAA ATs have embraced the opportunity to lead the way towards safe, successful campus reopening and resumption of competition