Welcome to MOspace
The MOspace Institutional Repository is an online repository for creative and scholarly works and other resources created by faculty, students, and staff at the University of Missouri--Columbia and the University of Missouri--Kansas City. MOspace makes these resources freely available on the web and assures their preservation for the future.
Recent Submissions
Item Economic analysis of the effects of paratuberculosis (Johne's disease) in dairy herds(University of Missouri--Columbia, 1985)In recent years, problematic animal diseases which reduce production efficiency and increase costs have become increas ingly difficult to control. Reduced efficiency can lead to a decline in profit levels for the producer and increased food costs for the consumer. Paratuberculosis is one such troublesome disease. It is a chronic debilitating infection that occurs in ruminants throughout the world and is known to have been in existence in the United States for at least 60 years. Studies have shown that the prevalence ranges from 8 to 20 percent. The infection is not easily diagnosed and information on disease control or eradication methods along with associated benefits and costs is lacking. This study demonstrates how animal diseases can be eco nomically evaluated by combining disease control methods or inputs with all other inputs in concert with the disease epidemiology. Analysis and evaluation is accomplished by con structing a simulation model of a representative Wisconsin dairy operation. Different control practices are considered including semi-annual fecal culture testing, vaccination, and removal of calves with rearing separate from the milking herd. A Markov chain approach is used to describe the epidemiology of the disease and assist in economic assessment of potential control practices. Four different initial disease prevalence rates are evaluated. Results are analyzed in terms of highest discounted re turns to labor and management as well as the effectiveness of the management strategy to minimize the number of infected cows over time. Initial prevalence rate had a significant impact on returns and the effectiveness of each strategy. Reduction and/or elimination of the disease from the herd is generally most effective when a testing program is included as part of the management strategy. Simultaneous achievement of both disease elimination and highest return objectives is not po s sible as measures to quickly eliminate the disease also reduces returns. In almost all cases disease control inputs did play an important role in the production process and long run profitability of the dairy operation.Item Characterization of isoaccepting transfer RNA species changes during friend cell erythroid differentiation(University of Missouri--Columbia, 1980)Erythroid differentiation in Friend leukemia cells can be induced by addition of dimethylsulfoxide to the culture medium. Hemoglobin represents 24% of the protein synthesis in differentiated cells. Therefore, Friend cells induced for differentiation may exhibit a marked change in tRNA population in order to effectively translate globin mRNA. Friend cells may prove to be a model system for the study of change in tRNA expression during differentiation and for the facilitation of specific protein synthesis. The chromatographic profiles of isoaccepting tRNA species from Friend leukemia cells were analyzed at five time points during a ninety-six hour period of dimethyl sulfoxide-induced differentiation. Sixty-four isoaccepting species of tRNA for sixteen amino acids were resolved by RPC-5 chromatography. The relative amounts of tRNA^phe, tRNA^ile, and tRNA^val species were maintained by the cells during differentiation; whereas the relative amounts of some of the isoaccepting tRNAs for the other thirteen amino acids changed significantly. Transfer RNA species containing the hypermodified nucleoside Q were among those exhibiting significant changes. Fluctuations in relative amounts of isoacceptors occurred between 36 and 72 hr after addition of dimethyl sulfoxide, corresponding to globin mRNA appearance and hemoglobin synthesis, respectively. In most cases, the predominant tRNA isoacceptors of uninduced cells were retained throughout differentiation. Notable exceptions were tRNA species for threonine, proline, and methionine. The two proline tRNA species present in uninduced cells were replaced by two different species in induced cells; the four threonine isoacceptors present early were represented by only two of the four in differentiated cells. These changes may reflect the cell's response to globin mRNA containing only two of the four threonine codons. Initiator methionine tRNA decreases in relative amount during the first 48 hours and then increases. This decrease is correlated to an initial lag in cell growth and protein synthesis. Some of the isoacceptors occurring in relatively smaller amounts were not expressed at all times. These changes possibly reflect the cell's functional adaptation of tRNA in differentiation for hemoglobin synthesis. The amount and distribution of Q-base-containing isoacceptors of tRNA^asn, tRNA^asp, tRNA^his, and tRNA^tyr were assayed. The amount of Q-base-containing tRNA species decreased in the first 48 hr after the induction, then increased again, indicating the level of Q modification is correlated to the process of differentiation.Item Hazardous metal wastes : landfill alternatives(University of Missouri--Columbia, 1983)This study was proposed to find technologically available processes which could be used as economically feasible alternatives to land disposal of hazardous wastes. The scope of the study was limited to heavy metal contaminated hazardous wastes generated in Missouri. Data on 95 such waste streams were taken from the Missouri Department of Natural Resources’ Hazardous Waste Generator Registration Files. Economic criteria reduced the number of streams under consideration to twelve. Two streams, an electric arc furnace flue dust and an electroplating wastewater treatment sludge, were chosen for detailed study. An electrothermic reduction roast process called the Plasmazinc process was proposed to recover iron, lead and zinc from the electric arc furnace flue dust. In this process, an electrically generated plasma is used to supply heat to a low shaft furnace which contains the dust and an excess of coke. A reducing atmosphere of carbon monoxide and hydrogen is maintained throughout the process so that lead and zinc can be collected as metals in a splash condenser. Iron is tapped from the bottom of the furnace. This process was developed by SKF Steel of Sweden. A profitability analysis for a Plasmazinc plant capable of processing 91,000 kkg of dust annually suggested that the dust would have to be delivered to the plant free of charge for it to be feasible. The discounted cash flow rate of return for this case was found to be 15.1%. A reverse osmosis unit integrated into the rinsing system was proposed to recycle nickel plating salts currently contaminating the electroplating wastewater sludge. As suggested by the generator, the 99.97 reduction of nickel in the sludge which would result could be sufficient to induce the EPA to grant a regulatory exclusion for the waste. The estimated savings in disposal and plating chemicals' costs would effect a projected discounted cash flow rate of return of 15.8%. Elimination of these two streams would reduce the amount of hazardous waste generated in Missouri and disposed of on or in the land by 10%.Item Role of interest groups in emerging nations : a case of Korea(University of Missouri--Columbia, 1974)Interest groups are one of the major sources of democracy in the politics of the emerging nations. The existence of influential interest groups may be the result of the lack of the authoritarian central power. An interest group is defined as a group of individuals who are linked by their special interests and who make demands upon decision makers for those special interests. The primary purpose of this study is to examine the nature and roles of interest groups in the political process in Korea as one of the emerging nations and to explore whether theory of interest groups in the politics of the western, developed nations is applicable to the study of emerging nations like Korea. The Particular concern is to delineate the relations between the development of interest groups and government control. The study is organized into eight chapters. In chapters I and II, the writer is mainly concerned with purpose, scope and method, conceptual framework, thoery, eight hypotheses about roles of interest groups in Korea, and operational procedure to test hypotheses. This study relies on both historical observations and field survey through interview. Chapters III and IV are devoted to generalizations about the role of interest groups and government control in the context of Korean politics, drawn from the literature on Korean politics. The history of Korean interest groups is divided into four major different periods: the Pre-Republic of Korea(1392-1948); the First Republic(1948-1960); the Second Republic (1960-1961); and the Third Republic (1961-1970). The particular concern is paid to discussion of degree of the government controls, the nature and activities of the interest groups, and the respective political environments. Chapters V, VI and VII analyze the survey data. Chapter V discusses the nature of organization of the Korean interest groups. It is found that interest groups in the South Korea are mostly influenced unilaterally by both governments and parties in terms of policy formation. It is also indicated that Korean interest groups suffer from lack of cohesion, intensified cleavages within their organization, particularly between rank and file members and their leaders, and lack of internal democracy. Chapter VI deals with the various reasons, techniques and variation of the government control, together with nature, demands and tactics of interest groups perceived by respondents. The present study shows that Korean interest groups are mostly suppressed by means of both legislation and direct supervision under the pretext of social disorder. But communist agitation is considered as the most unbearable reason for the repression of interest groups. When the government’s control is frequent, groups’ demands are relatively infrequent and vice versa. There is a high inverse correlation between the government’s control and the demands of interest groups but the nature of interest groups is independent from the government’s control. The tactics and nature of interest groups are broken into four distinctive categories: nonassociational, institutional, anomic, and associational. The survey supports the fact that as compared to western developed nations, nonassociational, anomic and institutional tactics and nature are relatively dominant but increasing importance of an associational nature has been shown to exist in the Korean society. Chapter VII deals with respondents’ attitudes toward interest groups and government control. Respondents generally believe that members of interest groups are either mostly apathetic or inactive and that their groups are largely weak due to governmental suppression. It is shown that groups increase their activities when government control decreases and vice versa. Chapter VIII contains a brief summary, reaffirmed hypotheses, future prosepcts and research implications. As the underlying conditions of interest groups become developed, Korean interest groups will show their growing importance in the Korean political process. Nevertheless, their significance is seriously limited by the government’s suppression.Item An investigation of acetate-requiring mutants of Chlamydomonas eugametos(University of Missouri--Columbia, 1976)Chlamydomonas reinhardi, a facultative autotroph, is a green alga capable of growth in the dark when supplemented with acetate as an exogenous carbon source. Another species, Chlamydomonas eugametos, is an obligate photoautotroph, that is, it can only grow in the light. The objective of this study was to investigate the basis of obligate photoautotrophy by a comparison of these two species and to select specific mutants. It was thought that facultative mutants of Chlamydomonas eugametos could be isolated which could be supported on acetate. Eight male and two female C. eugametos mutants with a stable requirement for acetate were recovered following ultraviolet irradiation and replica plating. Wild-types and mutants required light, CO2, and oxygen for growth. Investigation of the photosynthetic light reactions showed that the mutants were identical to wild-type, and that the acetate requirement did not replace the requirement for a photosynthetic reaction. Neither the wild-types nor the mutants would grow facultatively. Analysis of the photorespiratory pathway indicated that glycolate was not excreted under the culture conditions employed. Data from carbon supplementation studies suggested that the exogenous carbon sources were required to compensate for the inability of the mutants to carry on normal glycolysis and Krebs cycle functions. The presence of nitrate in the growth medium elicited significant differences in final titer in comparison to ammonium as a nitrogen source. As in C. reinhardi, these data suggested changes in metabolism were in response to the induction of nitrate reductase. A hypothesis is presented that the limitation of reducing power, possibly from the loss of the hexose monophosphate shunt, prevents sufficient biosynthesis to allow growth in the dark. This hypothesis is presented in relation to previous observations on C. eugametos as a possible explanation for obligate photoautotrophy.
Communities in MOspace
Select a community to browse its collections.