A spatial analysis was used to examine location of Mississippi’s forest products manufacturers and identify potential forest business clusters. A Poisson regression was used to examine the impact of transportation infrastructure, labor and availability of raw materials on location of these manufacturers. Spatial analysis indicated that manufacturers tended to cluster and identified four potential forest business clusters. Regression analysis indicated that volume of harvested sawlogs had a positive impact on location of primary and secondary forest products manufacturers, whereas volume of harvested pulpwood had a positive impact on location of only secondary forest products manufacturers. Presence of four-lane interstate highways was associated with decreased location likelihood for secondary manufacturers, whereas railway presence increased location likelihood. Presence of primary manufacturers had a positive impact on location of secondary manufacturers, whereas labor force also had a positive impact on location of secondary forest product manufacturers.

The coastal plain of the southeastern United States is historically wet pine savannahs, prairie, and hardwoods. However, many exotic species have invaded this area and become a serious threat to native forest ecosystems. Among those exotic species, Chinese tallow (Triadica sebifera) has become one of the most pervasive tree species in the southern coastal states, including Alabama, Mississippi, Louisiana, and Texas. Therefore, to understand the distribution and spread mechanisms has become important in the management and control of Chinese tallow in the southeastern United States. In this research, distribution and spread mechanisms of Chinese tallow were studied at multiple spatial scales, including regional, landscape, and stand. Effects of predisposing (community and landscape features) and inciting (natural disturbance and human activities) factors on Chinese tallow invasion had been evaluated by using a comprehensive data set (field data and Forest Inventory and Analysis data) and spatial statistical models. Results indicated that propagule pressure of Chinese tallow is the main force driving tallow dispersal at different spatial scales. Predisposing and inciting factors such as natural disturbances, anthropogenic disturbances, forest types, forestland ownerships, and landscape features are significantly related to the spread of Chinese tallow at different spatial scales. Regionally, Chinese tallow initially started to spread from southern Texas and Louisiana to the northeastern portion of the Gulf Coastal area. At landscape and stand scales, Chinese tallow has commonly invaded from edges of forests and habitats such as roads and firebreaks. Inciting factors, including hurricanes/storms and prescribed fires, could accelerate the spread of Chinese tallow at different spatial scales, especially in habitats that have previously been invaded. Compared to pine forests, it is easier for Chinese tallow to invade bottomland hardwood forests at the regional scale. The efficient dispersal distance of tallow seeds is 250-300 m, and its distribution is affected by the microtopography in forest stands. Management of Chinese tallow invasion should be focused at selected scales, such as landscape and stand levels, because of variations of site conditions.

Aflatoxin is a carcinogen produced by the fungus Aspergillus flavus that causes millions of dollars in agriculture losses in the southeastern US. This thesis examines the dispersal of A. flavus on two corn inbred lines, resistant (Mp313E) and susceptible (B73), which differ in total aflatoxin accumulation after infection with A. flavus. After inoculating corn kernels with the fungus an RNA analysis was used to determine the location (number of kernels away from inoculation site) and abundance of A. flavus at weekly intervals. A. flavus started its spread at 7 days after inoculation (DAI) on both corn lines. The B73 corn line showed a constant spread of 3.4mm per day until the entire ear was infected at 21 DAI. The spread on Mp313E did not proceed beyond 3 kernels away from the inoculation site following 7 DAI. The results are significant because they show a faster rate of spread than previously reported and they help quantify the ability of Mp313E to mitigate infection.

No description available.

No description available.

Trade and exchange of Steatite in the Susquehanna and Delaware river watersheds becomes more visible in the archaeological record approximately 3000 BC. This study will examine procurement and consumption of steatite bowls within the above watersheds of Pennsylvania between 3000 BC to 750 BC. Looking at the distribution of steatite sites in comparison to the distance from the quarry locations has enabled us to examine the trade and exchange model being utilized to acquire this material. The two models that are applicable to this region are direct procurement and down-the-line. Direct-procurement and down-the-line trade have distinct distribution drop-off patterns from the source. Using spatial analysis the distribution drop-off patterns from preferred steatite sources were examined. The data shows that steatite, a valued resource, was directly procured by a small number of groups within the watersheds examined. / Anthropology

This work presents methods used to obtain geometric models of spatial mechanisms which can be realized in hardware. Each model is created automatically from the kinematic description of a mechanism. The models are tested for interference between joints and links. Models with interfering links or joints are reshaped automatically into an interference-free configuration. An investigation of the relative efficiency of different interference detection techniques is discussed. A method for determining interferences based on vector loop equations was developed for this work. Other approaches for interference detection include parametric space and a method using parallel coordinates. 2000 line segments were randomly generated to test the three methods. No significant difference between the three techniques was found, but a coarse detection scheme was developed based on observations of intersection conditions in parallel coordinates. The coarse detection technique reduced interference detection times by 48%. The concept of joint positioning freedoms is presented formally for the first time. Using a unidirectional avoidance strategy along a straight line, these repositioning freedoms are exploited in a manner which guarantees the elimination of interferences for revolute, prismatic, and cylindric joints. A unique method for optimal orientation of spheric joint ball-cup pairs is described. Points from an inverse image of the attachment piece for the ball are mapped onto a unit sphere in the reference frame of the cup. The axis of a bounding cone is then used to align the attachment piece for the cup. The method minimizes the chances for collisions between the cup and the ball attachment piece. Elements which attach the joints are modeled as three segments. This has proven to be an optimal representation. Interferences with these elements are eliminated using the elliptical projection of circular paths onto a plane which is perpendicular to the axis of symmetry for an intruding object. Several examples are given illustrating the successful generation of interference-free spatial mechanism models. The mechanisms include an RSSR, an RPCS, an RCCC, and an RRRRRRR. / Ph. D.

No description available.

Landscape is about the relationship between people and place and in 2000 was defined by the European Landscape Commission (ELC) as "an area as perceived by people whose character is the result of natural and human actions and interactions”. In the 70s the reason for studying the landscape was because of the necessity of attributing a value to it. Nowadays the motivations behind managing, conserving and enhancing the landscape is because the landscape is the place where people belong to and, consciously or not, recognise themselves. In addition, people identify different landscapes on the basis of the particular combinations of the elements in the landscape. As a consequence a landscape can be distinguished from another on the basis of its character which, according to the Landscape Character Assessment (LCA) guidance for England and Scotland (C. Swanwick and Land Use Consultant, 2002), is defined as “a distinct, recognisable and consistent pattern of elements in the landscape that makes one landscape different from the other rather than better or worse”. This definition was the starting point of a PhD research project aimed at developing and implementing a methodology able to identify and quantify the character of the Scottish landscape through the application of GIS and statistics. The reason for doing this research was to provide the landscape architects and practitioners with a tool that could help them to define the landscape character types in a more consistent, objective, and scientifically robust way. One of the objectives of the research was to identify the spatial patterns formed by the landscape elements by taking into account the influence of the spatial location. The first law of geography, which states that "everything is related to everything else but near things are more related than distant ones" (W Tobler, 1970), was transposed in the assumption of the presence of spatial autocorrelation amongst the data which contributes to form spatial patterns within the data. Since landscape comprises of many elements, data were also multivariate, thus the analysis required a method of calculation able to deal simultaneously with multivariate and spatial autocorrelation issues. MULTISPATI-PCA, a spatially constrained Principal Component Analysis, was the statistical technique applied for the analysis of the data whose results showed that it was possible to detect the spatial structure of the data and that each spatial pattern corresponded to a distinct landscape. Despite their importance in forming the character of the landscape, aesthetic and perceptual aspects were not inlcuded in MULTISPATI-PCA analysis. It was preferred to test the technique only on data that were quantifiable in a more objective way. Perhaps taking into account the human perception of the landscape can be the starting point for future investigation.

Sea level rise (SLR) is one of the most damaging impacts associated with climate change. The objective of this study is to develop a comprehensive framework to identify the spatial patterns of sea level in the historical records, project regional mean sea levels in the future, and assess the corresponding impacts on the coastal communities. The first part of the study suggests a spatial pattern recognition methodology to characterize the spatial variations of sea level and to investigate the sea level footprints of climatic signals. A technique based on artificial neural network is proposed to reconstruct average sea levels for the characteristic regions identified. In the second part of the study, a spatial dynamic system model (DSM) is developed to simulate and project the changes in regional sea levels and sea surface temperatures (SST) under different development scenarios of the world. The highest sea levels are predicted under the scenario A1FI, ranging from 71 cm to 86 cm (relative to 1990 global mean sea level); the lowest predicted sea levels are under the scenario B1, ranging from 51 cm to 64 cm (relative to 1990 global mean sea level). Predicted sea levels and SST's of the Indian Ocean are significantly lower than those of the Pacific and the Atlantic Ocean under all six scenarios. The last part of this dissertation assesses the inundation impacts of projected regional SLR on three representative coastal U.S. states through a geographic information system (GIS) analysis. Critical issues in the inundation impact assessment process are identified and discussed.