2004 MU theses - Freely available online
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Item Whooping cough among Western Cree and Ojibwa fur-trading communities in subarctic Canada : a mathematical-modeling approach(University of Missouri--Columbia, 2004) Williams, Emily G.; Sattenspiel, Lisa"European colonization of the New World, the Americas and Oceania, had a vast influence on the native people of the Americas--both epidemiologically and demographically (Kunitz, 1994). The European domination of the New World was assisted, and in some cases achieved, by the infectious diseases that they carried with them to the Americas and Oceania. The arrival of Old World diseases to the New World resulted in pandemics that devastated and demoralized certain indigenous populations (Ramenofsky, 1987). These are known as virgin-soil epidemics because indigenous populations in the Americas had no previously acquired immunity to these infectious diseases (Crosby, 1976). This thesis uses a computer model to explore the effect of a virgin-soil epidemic in a native population. Epidemic models of two Canadian fur-trade communities were made which reflected the unique structure of each. The first community modeled was the Moose Factory post and nearby Albany in the James Bay area of Ontario and their fur-rich hinterlands during the 1850s. The second community under examination was the Norway House post of the Keewatin District of Manitoba during the period of 1918-1919. Figure 1.1 shows the study communities in their respective provinces within Canada. These communities were chosen because ethnographic data in the Hudson Bay Journals as well as parish records were available for the years under study Pertussis, or whooping cough, and influenza are simulated in these community models. The reasons for choosing pertussis are four-fold. First, pertussis was a significant and threatening infectious disease before the advent of vaccines; and second, an actual pertussis epidemic occurred at Moose Factory during the time period under study (1852-1862). The Hudson’s Bay Company Post Journals contain notations of an epidemic of whooping cough at Moose Factory in 1858--a time at which the Anglican Church parish records for Moose Factory became more accurate (Hoppa, 1998). Third, census data for Moose Factory was available for the year 1857. The fourth and last reason for choosing whooping cough for computer model simulations is that results from simulations of pertussis for the Moose Factory and Norway House regions can provide excellent insights into not only infectious diseases before the introduction of vaccines, but also how the structure of a community can affect the outcome of an infectious disease outbreak. Influenza was chosen as a comparison to pertussis for two reasons. The first is that influenza has been modeled by Sattenspiel and Herring (1998) for Norway House, Oxford House, and God’s Lake and these can be compared and to the pertussis simulations for the Norway House model in this thesis. Second, results from simulations of different diseases for the same communities can provide insight into how influenza and pertussis differ in terms of the severity of their epidemics. Comparisons of models of infectious disease, such as pertussis and influenza, can help provide an understanding of virgin-soil epidemics where few historical and ethnohistorical data exist."--Introduction.Item Application of a digital terrain model for forrest land classification and soil survey(University of Missouri--Columbia, 2004) Fabian, Christopher J.; Hammer, R. DavidLand characterization and classification is central to sound natural resource management. Forest land classifications usually lack sufficient detail, are not scale-adjustable, and are limited in scope and applications for the spectrum of relevant management decisions. Two alternatives for forest land classification have been proposed: a multifactor ecological land classification system (ECS) and a soil survey approach that is more geomorphic-based, comprehensive and forestry oriented than traditional classifications. Landforms influence important site factors, are easily observable features, and are relatively stabile in the landscape, so are a logical base for land classification systems. Geographic Information Systems (GIS) was used with Digital Elevation Models (DEM's) to produce Digital Terrain Models (DTM's) in the Missouri Ozarks. Terrain models produced from several DEM sources were evaluated for their accuracy in predicting slope, aspect and landforms on a 3691 ha area. The DEM's created from USGS hypsography were most accurate. Slope classes were correctly identified in 71.6% and aspect classes in 84.6% of observations. A rule-based approach to classifying landforms agreed with a field survey on 71.2% of the calibration site and 64.3% of the test site. A soil-geomorphic ecological approach using terrain modeling proved to be an accurate, consistent, efficient and cost-effective method.Item Simulating the effects of riparian zone delineation and management practices on landscape pattern and timber production(University of Missouri--Columbia, 2004) Bellchamber, Sara B.; He, Hong S.Best management practices (BMPs) are essential to giving the forest manager guidelines to follow that result in the least amount of negative impact on the forest landscape and corresponding riparian areas. The purpose of this research project is to determine the effect that different riparian zone delineations, based on BMP, will have on landscape pattern and timber production over time. LANDIS will allow for the application of three buffer scenarios (a 20 m buffer, a 100 m buffer, and a variable width buffer based upon soil and topographic characteristics) upon the same landscape and the analysis of the results that each technique will have over a long period of time. These boundaries determined the extent to which even-aged harvesting practices would be applied. Results indicated that the most influential variable in the simulation was the application of harvest. The variable width buffer most efficiently protected the stream by widening the buffer from the stream at areas that are more susceptible to erosion or pollutant discharge. Analyzing the effects of different buffering scenarios upon landscape pattern and timber volume provides forest managers with better tools for deciding the best action to take in balancing timber harvest with the biological integrity of streams.Item Modeling forest transition pathways for decision making in private forestry(University of Missouri--Columbia, 2004) Larson, Chad J.; Larsen, David R. (David Rolf)In the Central Hardwoods Region, 90% of forested lands are privately owned and the majority of harvested hardwoods come from non-industrial private forests. However, many landowners seek little professional advice when managing their forests and do not fully appreciate the consequences of management decisions on their land. This project developed a decision support tool summarizing a forest growth and yield model to explain simple forest stand dynamics to private non-industrial forest landowners in the Ozark Highlands of Missouri. To simplify forest growth modeling, predictions were limited to a 20 year period (long enough for potential forest change and short enough for landowners to have a vested interest in the land). Type-Size- Density classes were used to describe different forest structures. A set of FIA plots were grown in the Forest Vegetation Simulator (FVS); the initial and final Type-Size-Density classes were determined and simple transition probabilities calculated. Various forest management options were employed (no treatment, thinning from below, and diameter limit cut) and a multitude of forest attributes were assigned relative values for all Type-Size-Density classes. The categories of forest attributes developed include commercial timber products, noncommercial timber products, wildlife habitat, and risk. A database was developed to guide users from initial Type-Size-Density to likely future Type-Size-Density classes dependent upon the management option selected. The database further provides a representative photograph of each Type-Size-Density class along with scale bars indicating whether that class is good or poor at providing for each forest attribute.Item Equivalent circuit modeling of TMS plasma polymer coating system on cold-rolled steel(University of Missouri--Columbia, 2004) Young, Kevin, 1977-; Yasuda, H.Electrochemical impedance spectroscopy (EIS) during an accelerated corrosion (GM scab) test was used to differentiate between good and poor coating systems on coldrolled steel (CRS). The best coating was determined to be a cathodic Ecoat/ trimethylsilane (TMS) plasma polymer/oxide-free steel surface having an impedance modulus at low frequency of 109 ohms throughout the entire corrosion test. A spray paint primer and surface oxides both contributed to a degradation of corrosion protection evident from a significant drop in impedance (106_ ). With samples of known corrosion resistance, equivalent circuits were used to relate circuit elements to individual chemical processes taking place and identify the major factors contributing to failure of the coating. Two models (with and without plasma polymer film) were proposed and a good correlation to the EIS data was shown by a good visual plot fit and low chi squared values (<10-3). It was determined that the performance of the plasma polymer and conditions at the PP/steel interface are the major factors influencing the coating performance. The good coating system maintained a low double layer capacitance (10-9 F) and high charge transfer resistance (109_ ) relating to good adhesion at the coating/metal interface. The other samples, which exhibited poor adhesion, had a much higher capacitance (10-6 F) meaning water pool formation has created a water/metal interface. This in turn allows salt penetration for a higher corrosion rate showing up in the lower resistance (106_ ).