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Soil Health Assessment of the Sanborn Field Long-term Experimental StudyNorkaew, Saranya 16 April 2019 (has links)
<p> Soil health assessment uses a combination of potential indicators affecting soil processes to comprehensively monitor soil change, caused by cropping systems and soil management. The objectives of the study were to assess the effects of selected cropping systems, soil management and landscape slope positions on the soil health characteristics of the Sanborn Field long-term experimental study in Columbia, Missouri, United States. Soil samples were collected on each of four dates over two years (8<sup>th</sup> May 2014, 4<sup>th</sup> September 2014, 1<sup>st</sup> April 2016, and 18<sup> th</sup> August 2016) from selected plots to address each objective, and these time samples were used as replications. Soil physical, chemical, and biological characteristics were analyzed in the laboratory for these samples to assess soil health using the Cornell Comprehensive Assessment of Soil Health (CASH) method. To assess soil health in this study, soil health scoring was determined used R-studio version 1.1.149 to relate the interaction of cropping systems, soil management, and slope positions. Most soil resources on Sanborn Field are a poorly-drained claypan soil classified as a Mexico silt loam (fine, smectitic, mesic Vertic Epiaqualf). In addition, soil samples collected from Tucker Prairie was used as a proxy for the original state of Sanborn Field soils. The first study was conducted to evaluate the effects of long-term cropping systems on soil health properties. The results from the characterization indicated that continuous timothy (<i>Phleum pretense</i> L.) and warm season grass treatments were classified with very high soil health scores, and the lowest score was found for continuous corn (<i>Zea mays</i> L.). In addition, results showed strong positive linear associations between soil organic carbon, total nitrogen, potentially mineralizable nitrogen, active carbon, microbial biomass, and water stable aggregates; while a strong negative linear correlation existed between each of these properties and bulk density. The second study was conducted to evaluate the effects of long-term annual applications of no fertilizer, full fertilizer, and manure on soil health measurements of selected cropping systems. Different cropping systems, including continuous corn, continuous wheat (<i>Triticum aestivum</i> L.), corn-wheat-red clover (<i>Trifolium pretense</i> L.) rotation, and corn-soybean (<i>Glycine max</i> L.)-wheat rotation treatments were used in this study. Results showed that annual dairy cow (<i>Bos Taurus </i>) manure applications had the greatest effect on all soil health indicators and had the largest overall soil health score compared to full fertility and no fertilizer treatments. Moreover, continuous wheat with manure application presented the best combination of effects on soil properties with the largest score for most soil health indicators and an overall health score of 82 out of 100 classified as very high which is the best. The last study evaluated the effects of landscape slope positions on soil health properties of the long-term experiment. Results showed that the summit position had the highest overall soil health score while the lowest score was found on the shoulder position. However, there were no significant differences along the transect slope for water-stable aggregates and bulk density. There were significant differences along the transect for the biological properties such as soil organic carbon, active carbon, potentially mineralizable nitrogen, and microbial biomass. Results of this study illustrate the effect of selected variables on soil health and provide the recent addition of using biological characteristics to account for soil health properties. It is important to remember that this study of the long-term Sanborn Field experiment is just for a small-sized plot area. Future studies of soil management effects on soil health need to account for their own field conditions and their own unique environment.</p><p>
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The human resources management (HRM) practices a panacea to the challenges of the Minstry for Home AffairsGamedze, Sipho Benedict 27 September 2012 (has links)
As the public sector continues to face competitive challenges from the general public, the need for better service delivery and increased productivity has become extremely important. The increased need for optimum service delivery in public sector institutions like the Ministry for Home Affairs has had significant impact on its operations. However, little is known about the challenges faced by the Ministry for Home Affairs regarding the causes of the inefficiency. A range of organizational factors can affect the nature, effectiveness, excellence and novelty of service provision to members of the public.
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Evaluating Methods to Describe Dietary Patterns of Lake Michigan SalmonidsBenjamin S. Leonhardt (5930720) 18 December 2018 (has links)
<div>Documenting trophic relationships in aquatic ecosystems can facilitate understanding of not only system processes, but also the potential responses of food webs to stressors. Often, trophic studies assume consistent behavior and trophic roles among individuals in a population, but intraspecific diet variation, such as individual specialization, can play a critical role in food web complexity and can promote ecosystem resilience. In Lake Michigan, the introduction of invasive species (e.g., zebra mussel, Dreissena polymorpha; quagga mussel, Dreissena bugensis; round goby, Neogobius melanostomus) and reduced nutrient loading has resulted in changes in nutrient dynamics, system productivity, and community composition over the past two decades. As a result, abundances of many forage fish have declined, including alewife (Alosa pseudoharengus) which have historically supported the five dominant salmonid species of Lake Michigan (brown trout, Salmo trutta; Chinook salmon, Oncorhynchus tshawytscha; Coho salmon, Oncorhynchus kisutch; lake trout, Salvelinus namaycush; rainbow trout, Oncorhynchus mykiss). With these ecosystem changes, there is uncertainty as to the extent of how different species of salmonids will transition to alternative prey items (e.g., round goby). Common methods for examining diet patterns and trophic linkages include stomach content analysis, stable isotope ratios (e.g., δ13C and δ15N), and fatty acid composition, but these methods vary in temporal resolution and have differential biases. Furthermore, elucidating agreement of these trophic indicators and whether or not agreement is consistent across species can improve their use in future food web studies. The first research chapter of this thesis investigated the diet complexity of Lake Michigan salmonids by evaluating stomach content composition, diversity, and potential specialized consumption of different alewife lengths. Stomach contents revealed that Chinook salmon almost exclusively consumed alewife and had a lower diet diversity compared to the other four species, which consumed round goby (brown trout and lake trout), aquatic invertebrates (Coho salmon), and terrestrial invertebrates (rainbow trout) in addition to alewife. Although there were clear spatio-temporal and size-related feeding patterns for each species, much of the variation in diet composition and diet diversity was present at the individual-level. Additionally, salmonid species appeared to consume the entire size range of alewife that were available to them and individually specialized on alewife lengths. Due to their reliance on alewife, it is likely that Chinook salmon may be more negatively impacted than other salmonid species if alewife abundance continue to decline in Lake Michigan. The second research chapter assessed the agreement of multiple trophic indicators. Although we found agreement among trophic indicators across the five salmonid species using linear and logistic models, particularly between stomach contents, δ13C, and fatty acid 16:1n-7, there was significant variation in relationships across species, potentially due to variation among salmonids in specific prey items consumed (e.g., alewife and round goby) and species-specific regulation of fatty acids. Additionally, δ15N estimated from stomach contents using linear mixing models were typically greater relative to observed δ15N, which may suggest small alewife were underrepresented in stomachs of 2016 angler-caught salmonids. Lastly, stomach contents underestimated benthic resource use by rainbow trout, which may be related to biases associated with fish collection methods and stomach content analysis. Overall, the results of trophic indicator comparisons indicate that caution should be taken when generalizing trophic relationships across species and to consider biases associated with trophic indicators, especially when relying on a single diet metric.</div>
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An investigation into the forecasting of skills in nuclear decommissioningGrabrovaz, Meaghan January 2017 (has links)
This study explores the nature of skills forecasting in nuclear decommissioning and that which makes skills forecasting information useful. The study adopts a pragmatic approach using an interpretative, qualitative case study research design and draws on aspects of a critical realist approach to uncover, deconstruct and challenge some ‘norms’ in skills forecasting. The study makes an original contribution to knowledge through the identification of nineteen factors that influence skills forecasting in the nuclear industry. It also generates a baseline of knowledge on the theory and practice of skills forecasting and management through a review of the literature on skills, forecasting, skills forecasting and workforce planning and relevant aspects of public sector management and HRM. The study documents and compares current skills forecasting practice amongst UK site licensed companies and selected supply chain companies. Such research has not previously been conducted in the nuclear decommissioning industry. This answers research questions about why, and how, different groups in the sector perform skills forecasting and how variations in approaches affect the information produced. It also answers research questions about who uses skills forecasting information, and how. Together with a review of current problems with skills information, this contributes to an understanding of what makes skills information useful. The research evidences that while the industry has some common features with other High Reliability Organisations, there are unique dimensions which make this research significant. Some ‘norms’ operating in skills forecasting were challenged including how it is being used, eg as an agent for change by some groups, and assumptions about the potential availability of skills from the supply chain. The literature review was used to construct a practical-ideal type, an approach derived from classical pragmatism offering a version of a nearly ideal process, on the understanding that this is socially constructed and subject to continual change. Existing practice is evaluated against this practical-ideal type in a unique application of this methodology in the nuclear decommissioning context.
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The Development of Ecological Functions in Created Forested WetlandsCharles, Sean P. 01 January 2013 (has links)
Wetland mitigation has become a 2.4 billion dollar per year industry in the U.S. and in Virginia it leads to the replacement of 77 ha of palustrine forested wetlands (PFWs) per year with mitigation wetlands, including created forested wetlands (CFWs). Mitigation hinges on the idea that compensation wetlands lead to “no net loss of wetland function” when compared to impacted wetlands. We assessed the functions of provision of habitat and biogeochemical functions associated with production of biomass, the retention and removal of nutrients and the accumulation of soil C over 8 years in seven CFWs of approximately 11 and 20 years and compared them to natural reference wetlands (NRWs). CFW plant communities were similar to NRWs in all measured parameters in the herbaceous and shrub/sapling strata and in all strata combined. However, non-native dominance showed a significant positive linear relationship with CFW age. In the tree strata, 11 year old (yo) CFWs had lower richness than NRWs and both age classes of CFWs had lower FQI than NRWs. NRWs held 10 to 20 times more carbon in woody biomass than CFWs. Tree species composition was significantly different between CFWs and NRWs, however NRW trees were similar to CFW saplings. 11 yo CFWs held lower percentages of C, N and P and had higher Db than NRWs in both the 0-10 and 10-20 cm depth. 20 yo CFWs developed similar levels of %C, %P, bulk density (Db), and nutrient ratios in the surface and displayed rapid increases in %C and %N over 8 years. However, CFWs offered 45% lower soil total soil C storage and 50% lower %N. Furthermore, all CFWs stored lower nutrient levels than NRWs in the 10-20 cm soil depth. We found that FQI correlated positively with total C accumulation rates in woody biomass and soil C, indicating that biogeochemical function and the provision of habitat can be complimentary in CFWs. Finally, 11 and 20 yo CFWs adhered to the regulatory performance standards established for Virginia in terms of stems per ha and wetland indicator status, but all wetlands (including NRWs) failed to achieve <5% non-native species cover.
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Error Analysis in Tidal Wetland Inventory Change Detection: Comparison of Historical Mapped Wetlands of the Achilles Quadrangle between 1976 to 1989Nelson, Stacy A. C. 01 January 1995 (has links)
No description available.
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Fatty Acids and Hydrocarbons in the Surface Waters of the York RiverWindsor, John G. 01 January 1972 (has links)
No description available.
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Acute Toxicity of no 6 Fuel Oil to Intertidal Organisms in the Lower York River, VirginiaHyland, Jeffrey L. 01 January 1972 (has links)
No description available.
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FRNA Coliphages as a Viral Indicator of Sewage Pollution in an EstuaryBoyd, David Miller 01 January 1990 (has links)
No description available.
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The Effect of a One-Meter Sea-Level Rise on Tidal Wetlands in Gloucester County, VirginiaHill, Paula Lindsey 01 January 1992 (has links)
No description available.
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