The effects of exercise, training, and a supplemental lecithin/corn oil diet on acid-base homeostasis and blood gases in arterial and central venous blood were examined during repeated sprint exercise in horses. Differences between temperature measurement sites for the adjustment of pH and blood gases during exercise was also investigated. The independent variables, strong ion difference (SID), total weak electrolytes ([A_tot]), and pCO₂, had different effects on the dependent variables, [H⁺] and [HCO₃⁻], and these influences changed depending on blood sampling site (arterial or central venous), and exercise intensity. Data supporting the involvement of the chloride shift during repeated sprint exercise in the horse was observed for the first time. Training resulted in increased plasma [Na⁺], [K⁺], [SID], albumin, free fatty acids, and beta~-hydroxybutyrate concentrations, and decreased blood lactate ([Lac⁻]), plasma [Cl⁻], [H⁺], cholesterol, and heart rate during exercise. Horses consuming the corn oil/lecithin supplemented diet had a higher pvCO₂, [HCO₃⁻], [Cl⁻], cholesterol, and glucose, and lower blood [Lac⁻], [H⁺], and triglycerides during exercise. The sprint training and corn oil/lecithin diet may act synergistically to enhance performance in horses’ by maintaining a lower [H⁺] during high intensity exercise. There were differences between skin, rectal, blood, and muscle temperatures during incremental exercise and recovery in horses. The pH and blood gases adjusted to rectal, blood, and muscle temperatures were also different during exercise and recovery. Muscle and blood temperature may be predicted from rectal or skin temperature during exercise, and from skin temperature during recovery. / Ph. D.

The primary objective of this study was to empirically determine the relationship between restaurant images and loyalties toward seven competing casual dinner house restaurant chains, and to understand the nature of their competition by matching patronage behavior toward alternative restaurant chains with perceptions of alternative restaurants) on particular image attributes. The canonical correlation analysis revealed that the measures of image had significant impact on both loyalty measures toward selected casual dinner house restaurant chains: (1) patronage intentions and (2) proportions of patronage. Furthermore, the interpretation of the canonical functions revealed the nature of competition in terms of market segments and positioning. The research findings of this study imply that the obtained restaurant image is not only an analytical device to diagnose the weaknesses and strengths possessed by each restaurant relative to other restaurants, but also a predictive tool for loyalty patterns toward alternative restaurants. This study contributes to the existing consumer patronage behavior literature by providing empirical research results for the interrelationships between multi-store image measures and multi-store loyalty measures. Further, this research illustrates the usefulness of canonical analysis, which is a powerful technique for exploring the relationships between one set of variables and a second set of variables. Lastly, this study is of empirical value to restaurant management. In terms of offering strategic guidelines, this study shows the magnitude of the relationships and explains the nature of competition in a local market by linking consumer's loyalty behavior toward one or more restaurants with the image strengths/weaknesses of alternative restaurants on salient image dimensions. As a consequence, restaurants can use this information in their repositioning strategies to improve or change their image. / Ph. D.

A review of the literature revealed a need for programs serving students with speech/language disorders that do not adversely affect their educational performance. This study sought to locate non-special education sponsored speech-language programs designed to serve students found ineligible for special education services under the Individuals with Disabilities Education Act (IDEA) (Public Law 101-476). Eight states were identified as offering non-IDEA speech-language services in the regular education program for students found ineligible under special education law. State education agency personnel responsible for statewide public school speech-language programs were surveyed in these states to seek specific information about the non- IDEA programs offered. Speech-language pathologists employed in rural and urban public school settings in these states were surveyed to note whether the non-IDEA services were offered in their school districts. Specific eligibility criteria were examined to determine how decisions are made regarding the enrollment of students with speech/language disorders in non-special education sponsored programs and special education sponsored programs. Guidelines for implementing and regulating speech-language programs were requested from each state education agency for the purpose of compiling best practices in the field. The study revealed that non-IDEA speech-language programs were designed to serve students with minor or mild articulation, language, fluency, and voice disorders. Eligibility criteria used in placing students in these programs were similar to those used in placing students in special education sponsored speech-language programs. Formal regulations/guidelines were reported in one-half of the states but only one state had published guidelines available. These results provide support for more states to offer alternate speech-language programs to meet the needs of students outside of special education. An in-depth study of eligibility criteria used in serving students in IDEA and non-IDEA speech-language programs is warranted. / Ed. D.

Longitudinal data, in which a series of observations is collected on a typically large number of experimental units is one of the most frequent and important sources of quantitative information in forestry. The dependencies among repeated observations for an experimental unit must be accounted for in order to validate statistical estimation and inference in modeling efforts. The recent advances in statistical theory for correlated data created a body of theory which will become of increasing importance as analysts realize the limitations of traditional methods that ignore these dependencies. Longitudinal data fosters research questions that focus on the individual experimental unit rather than the population as in classical cross-sectional data analysis. Mixed model techniques have emerged as powerful tools to address research problems of this kind and are treated extensively in this dissertation. Over the last years interest in modeling quantal responses that take on only a countable, discrete number of possible values has also increased throughout the discipline. The theory of generalized linear models provides the groundwork to embody quantal response models into the toolbox of applied analysts. The focus of this dissertation is to combine modern analytical tools for longitudinal data with regression methods for quantal responses. Special emphasis is placed on ordinal and binary data because of their prevalence in ecological, biological, and environmental statistics. The first chapters review the literature and introduce necessary theory. The second part of this dissertation consists of a case study in which binary and ordinal fusiform rust response on loblolly and slash pine is modeled in a longitudinal data base provided by the East Texas Pine Plantation Research Project. / Ph. D.

The ability to influence the movement of ions across a bulk liquid membrane through use of an electrochemically modifiable crown ether will be examined in this work. This process will be referred to as electrochemical facilitated transport. The design and synthesis of a new ferrocenophane crown ether for use in this work will be presented. Experiments using this model compound were designed and performed to demonstrate the ability to move an ion across the membrane both with and against (downhill and uphill) its concentration gradient. Experimental results are presented for the movement of silver perchlorate and thallium chloride across methylene chloride bulk liquid membranes using 2,5,8,11,14,17,20-heptaoxa[21](1,1’)ferrocenophane-1,21-dione as the membrane carrier. As a further enhancement to the understanding of the process of electrochemical facilitated transport, computer simulation modeling tools were developed with special emphasis placed on the electrochemical and carrier/ion complexation issues that are integral to the process. / Ph. D.

Seed tubers of ‘Yukon Gold’ potato (Solanum tuberosum L.) exhibit strong apical dominance, resulting in low stem density after planting. After emergence, the terminal buds reimpose apical dominance on the rest of the canopy leading to production of few secondary branches. Therefore, several experiments were conducted at the Virginia Polytechnic Institute and State University Kentland Research Farm, Blacksburg in 1992, 1993, and 1994 to evaluate the effects of topping [(excising 2-3 cm from the terminal buds at 1 to 2 weeks after the date of plant emergence (WAE)], stage of vine cutting at ground level, and main stem density on canopy growth, tuber bulking rate, and tuber yields of potato. Topping (3 years) and vine cutting (2 years) at 1 WAE resulted in more uniform plant stands and increased average yield of US No. 1 tubers of ‘Yukon Gold’ by 16 and 14%, compared to untopped and uncut plants, respectively. When plants of ‘Kennebec’, ’Superior’, and ’Yukon Gold’ were topped in 1994, yield of US No. 1 tubers increased by an average of 10%, indicating that topping could be used to improve tuber yield of potato cultivars exhibiting different growth habits. The increased tuber yields following topping resulted from a combination of increased leaf area duration and increased period of tuber bulking. Cutting vines of ‘Yukon Gold’ at 2, 4, and 6 WAE in 1992 and 1993, decreased yield of US No. 1 tubers by 11, 69, and 38% and by 19, 56, and 48%, respectively. Yield of US No. 1 tubers increased with increased stem density and increased in-row spacing. Interaction effects between in row spacing and topping were significant. Control plants of ’Yukon Gold’ produced higher tuber bulking rates and yield of US No. 1 tubers than topped plants at 15 cm in-row spacing, while topped plants had higher tuber bulking rates and yield of US No. 1 tubers than control plants at 20, 25, and 30 cm in-row spacings. Neither topping nor in-row spacing increased the incidence of hollow heart of tubers in 1994. The results showed that the difference in tuber yield between topped and control plants was greater during long growing season and topped plants should be spaced at 25 cm in-row in order to obtain maximum tuber yield. / Ph. D.

This study examines Pakistan's energy policy since the mid-1980s when the government decided to pursue the path of deregulation and privatization of the energy sector. It identifies and analyses the underlying factors and mechanisms that were responsible for the re-orientation of energy sector policies from the state to the market. Though there are important differences between the previous statist and the present market approaches, there are also fundamental structural commonalities between them. These commonalities revolve around the key points of capital and technology dependence of the energy sector development on sources outside the national economy. It is argued that both of these approaches are in fact variations of dependent development. The influx of foreign investments which the new policies are designed to attract, will create new claims on the country's foreign earnings in the form of private debt service and repatriation of profits, etc. As energy so produced will not be exported and therefore not directly generate any hard currency, these claims can only be satisfied through either a major expansion in exports or by additional foreign borrowing. This study reveals inveterate structural limitations to major expansion in export sector earnings. Further, recourse to the enhancement of traditional exports will only serve to intensify dependency. As, the national economy does not have the capacity to sustain the new hard currency claims, Pakistan will be compelled to borrow externally and thus sink deeper into the debt trap. In contradistinction to dependent development strategies for enhancing energy production, are alternative strategies that mainly rely on mobilization of domestic revenue and technical resources along with a selective utilization of external inputs. To solve Pakistan's energy crisis in the strategic sense, this study recommends the creation of an indigenous capacity to develop energy resources. Policies are suggested that would mitigate and eventually break the vicious cycle of dependency. But to do this, the state will have to play a new type of a role, different from that of the past as well as the one suggested by current policies. The real challenge is to bring about major organizational innovations in the public sector, rather than the current emphasis on dismantling it. / Ph. D.

Alluvial fans along the western footslopes of the Blue Ridge province, Virginia range over a linear distance of at least 200 km and spread westward up to 4.8 km. Certain soils formed on the fans appear old and highly weathered. Little detailed physical, chemical, or mineralogical data is available about the soils. Concepts about their origin, age, and genesis are vague. This research was conducted in Botetourt, Augusta, Rockingham, and Page counties, Virginia with the intent to gain information about soil properties and to clarify genetic concepts. The objectives were to 1) characterize selected alluvial fan soils distributed along mountain footslopes, 2) show two depositional units compose the sola by using multivariate data analysis procedures, 3) determine the genesis of the soils, and 4) find out if weathered rock bulk density (p_r_b) and free Fe (Fe_r) are different among sites and, if so, what soil and/or rock properties correlate to ρ_r_b. Transitional horizons, fragipans, and weakly to moderately developed argillic horizons compose the upper Depositional unit (unit A). Reticulate redoximorphic features and highly weathered quartzite rocks are found in the 2Bt horizons (unit B) where clay approaches 60 percent at 2m. Up to 25 pedons were sampled within a 50 m² grid at four Sites. Paired samples from the pedons were analyzed by principal component analysis (PCA). The PCA loadings show Significant soil properties contribute about equally to the first principal component. The second principal component loadings show clay-free properties best define the discontinuities. Discriminant functions clearly separate unit A from unit B (P < 0.001). Clay and free Fe abruptly increase at the discontinuity. Hydroxy-interlayered vermiculite (HIV) dominates unit A clay fractions; whereas, kaolinite is abundant in unit B. Gibbsite is higher in unit B than unit A. Weathered ρ_r_b is not different among five sites on a bajada within the central part of the study area, but it is different from five other Sites on either end of the study area. Free Fe variation among rocks within sites accounts for 70.6% of the variation, but the variation among sites is only 12.7%. Weathered ρ_r_b most strongly, although negatively (r = -0.76), correlates to clay-fraction HIV. Time and climate are considered the most influential factors controlling soil development on the Blue Ridge fans. A substantial but unknown amount of time passed before unit A was deposited over unit B. Clay percentages, clay mineralogy, and chemical properties indicate the soils formed from materials additional to the quartzite rocks. Vestiges of these materials are no longer present in the soils. Rock weathering patterns suggest the soil weathering environment has changed. The fan soils are similar to other soils in Virginia dated to late Miocene. The alluvial fan soils are probably related to the dated soils, and they may also relate to other soils reported on transported deposits elsewhere in the southern Appalachians. / Ph. D.

Cotton seedling disease caused by Pythium ultimum Trow and Rhizoctonia solani Kühn occurs worldwide in soils ranging from pH 4.5 to 8.5. Studies with cotton have not yet established the relative importance of two classes of secondary metabolites synthesized by soilborne pseudomonads, siderophores (sid) (low molecular weight Fe⁺³ chelators) and antibiotics (ant), in the suppression of these pathogens. Greenhouse bioassays to screen for rhizosphere competent strains identified a single strain of Pseudomonas chlororaphis (L-850), that produced siderophores and multiple antifungal antibiotics, including one or more phenazines. A Tiff Image Analyzer (TIA) software program was developed that allowed assessment of wild-type (wt) L-850, and (ant) and (sid) mutant populations as a function of cotton root surface area (cm²) in the absence of soil irrigation. Bacterial density and distribution patterns on roots evaluated 22, 36, and 50 DAP, in two pathogen-free soils (pH 5.7, high Fe⁺³, high phosphorus (P); pH 8.0, low Fe⁺³, low P) indicated that populations of both wt and mutants persisted after day 22 at levels between log 4.6 (lower laterals) to log 6 cfu/cm² (upper tap) even as total root area increased 122% from day 22 to 50. Population densities of all strains were consistently 1/8 to 3/4 log unit lower in the pH 5.7 soil on the lower tap and upper lateral roots, respectively. The loss of siderophore production appeared to enhance the rhizosphere competence of strain L-850. For greenhouse trials with three pathogen inoculum densities (low, intermediate, high) protection against preand postemergence damping-off (phase 1) and hypocotyl/root rot of young plants (phase 2) by the (sid) and wt strains was similar (P = 0.05) whereas, protection by seed treatment with the (ant) mutant was reduced. The level of suppression provided by L-850 was equivalent (P = 0.05) to the standard fungicide at low and intermediate pathogen pressure. These studies demonstrated a minimum contribution of siderophores in the biological control of cotton seedling disease and established a significant role for antibiotic biosynthesis over a range of soil physical and chemical characteristics. / Ph. D.

Macrophages (MΦ) and T cells mediate helper, effector, and cytotoxic activities. Tumor growth changes the phenotypic and functional characteristics of MΦ and T cells and shifts them toward suppressor phenotypes and functional activities. Tumor growth changed MΦ DNA synthesis when activated through Mac-1 and Mac-3 surface molecules, which suggests that specific receptor-ligand interactions modulate MΦ cell-cycle kinetics differently in the tumor-bearing host (TBH). Tumor growth changed MΦ responsiveness to MΦ colony-stimulating factor (M-CSF). M-CSF did not reverse decreases in autorecognition caused by TBH MΦ, and increased TBH MΦ suppression during T-cell alloreactivity. TBH suppressor activities were associated predominantly with MHC class II MΦ. TBH class II⁻ MΦ quantitatively and qualitatively suppressed T-cell autoreactivity partly by dysregulation of interferon-gamma (IFN-y), interleukin-4 (IL-4), and prostaglandin E₂ (PGE₂) production. TBH MΦ had aberrant regulation of granulocyte-macrophage colony-stimulating factor (GM-CSF). TBH MΦ produced less GM-CSF than normal host (NH) MΦ. GM-CSF failed to increase class II molecule expression on TBH MΦ, and TBH class II⁻ MΦ became more suppressive when cultured with GM-CSF. TBH MΦ GM-CSF dysregulation involved PGE₂ and interleukin-10 (IL-10). Tumor growth also affected CD4⁺ and CD8⁺ T cell phenotype and function. The in vivo percentage of CD8⁺ T cells significantly increased during tumor growth and these cells significantly suppressed T-cell allorecognition and autorecognition. TBH CD8⁺ T-cell suppression was mediated partly through dysregulation of IFN-y, IL-4, and PGE₂ production. TBH CD4⁺ T cells produced less GM-CSF than NH CD4⁺ T cells, and GM-CSF dysregulation was linked partly to increased sensitivity to IL-10 and transforming growth factor-β₁ (TGF-β₁). Tumor growth changed CD4⁺ T cell responsiveness to cytokines associated with T cell activation. TBH CD4⁺ T cell proliferation was suppressed significantly by taxol. This research also suggests that taxol can promote tumor regression. Taxol disrupted tumor cell growth through cytostatic and cytotoxic mechanisms, and increased tumor cell susceptibility to taxol-induced, MΦ-derived lytic molecules. Taxol also disrupted autocrine regulation of TGF-β₁ and stimulated apoptosis. Collectively, these studies suggest that tumor-associated changes in MΦ and T cells involve cytokine dysregulation. |Immunotherapeutic approaches may partly or completely reverse suppressor immune cell activities during tumor growth. / Ph. D.