see document / Master of Science

Tourism in North Cyprus provides recreation opportunities for visitors and creates employment and income. Even though there has been a substantial growth in tourism during the last three years, there has been, if any, limited amount of research that has examined and evaluated the nature of tourism offerings as destination attributes and their associated marketing and management concerns with respect to satisfaction and performance levels of such attributes in North Cyprus. The objective of this study is to examine if there are travel behavior differences in the importance and performance levels of destination attributes by different age groups and origin (nationality) of visitors in North Cyprus. More specifically, the study examined the following two propositions: (1) perceived importance and performance of destination attributes will vary by origin of visitors, and (2) perceived importance and performance of destination attributes will vary by age of visitors. First, he study developed an instrument, which was then used to evaluate visitors' perceptions of preselected destination attributes associated with North Cyprus. By using this instrument, this study delineated the perceived level of importance of each destination attribute together with how well the destination provided and met such attributes and activities. Importance-Performance Analysis (lIP) is utilized for this study. This is an evaluative technique which involves four major steps. First is the development of an attribute list, second is to develop a questionnaire from these attributes, third is to ask the respondents to rate these attributes according to importance and satisfaction levels, and the final step is done by analyzing the results and displaying them on an action grid. The results revealed differences in the importance mean scores of destination attributes and their perceived performance among the three identified age groups. The findings of the study also indicated that ratings of destination attributes and activities show some variations by origin (nationality) of visitors. The study concludes with marketing and management implications as suggested by study findings. / Master of Science

Macrophages (Mφ) are a major immune cell involved in anti-tumor responses. Mφ activities such as tumor cytotoxicity. presentation of tumor-associated antigens, and stimulation of anti-tumor lymphocytes are all involved in the battle against tumor growth. However, other Mφ activities such as cell growth promotion, angiogenesis, and suppression of anti-tumor lymphocytes aid in tumor growth. This dissertation discusses how tumors control Mφ activities to create favorable environments for tumor growth. Assessment of tumor- and Mφ-derived molecules has enabled me to design models of communication between tumors, Mφ, and other immune cells. A major research focus was to determine how tumor-derived molecules induce Mφ suppressor activity and control Mφ cytotoxicity. Tumor growth induced Mφ to suppress T lymphocyte proliferation by increasing Mφ production of the suppressor molecules prostaglandin E₂ (PGE₂), nitric oxide (NO), and tumor necrosis factor-α (TNF-α). A major finding was that TNF-α's normal up-regulatory action on T-cell proliferation switched to a suppressor action when Mφ were present. The autocrine action of increased TNF-α levels during tumor growth stimulated Mφ PGE₂ and NO synthesis, which suppressed T-cell proliferation. / Ph. D.

The positions of sequences necessary for transcription from the promoter located at map unit 4 of the bovine parvovirus (BPV) genome were determined. The autonomous parvoviruses, of which BPV is a member, contain two transcriptional units with promoters active in temporal order during infection. BPV proteins also appear in the same temporal order; the nonstructural (NS) proteins are produced before the capsid proteins. Northern blot analysis of BPV RNAs suggest that, like human parvovirus B19, all transcripts of BPV are initiated from a single promoter. A reporter construct was created by cloning the sequences from BPV containing the TAT A box located at nucleotides (nt) 250 - 254 upstream of the luciferase gene. A series of mutants were generated by deletion of restriction endonuclease fragments. Expression was assayed by transient expression of the constructs in transfected bovine fetal lung (BFL) cells, derived from the natural host. The data indicates that expression can be directed from the sequences containing the TAT A box. Analysis of expression of the deletion clones show that sequences from nt 120 - 170 of the BPV genome are also required for transcription. A search of these sequences reveals at least two consensus binding sites for cellular transcription factors. These are AP-I and the major late transcription factor (MLTF). MLTF has been shown to induce transcription from the early promoter of the dependovirus adena-associated virus (AA V). The presence of viral proteins provided in trans decreases expression from all constructs, with one exception. Expression, when nt 0 - 50 are deleted, is increased in the presence of mutant BPV NS-I. Feedback inhibition of P4 expression by NS-I, the P4 gene product, is seen in H-l, a rat parvovirus. The expression of BPV proteins in synchronized HeLa cells, which are not a natural tissue culture host was examined to determine the effect of a non-permissive host on BPV transcription. Expression of viral proteins in some parvoviruses is blocked in non-permissive cells. A block in transcription is seen during infection of non-permissive cells by B 19. AA V P5 expression is negatively regulated without co-infection of a helper virus, a non-permissive state. Luciferase activity was 570/0, compared to BFL cells. and a similar decrease in expression in the presence of viral proteins was observed. Viral nonstructural and capsid proteins could be detected by immunofluorescence, but only in the cytoplasm, suggesting that expression of viral proteins necessary for replication was not the block to a productive infection, but rather their translocation to the nucleus, as seen during restrictive H-l infection of transformed cells. BPV proteins have been observed localized to nuclear foci of transfected, synchronized BFL cells. The subcellular localization of viral proteins was detected by indirect immunofluorescence labeling using antiserum that recognizes both nonstructural and capsid proteins. Punctate nuclear staining has not been observed routinely during BPV infection or transfection of actively dividing cells. AA V proteins expressed in either BFL and HeLa cells, synchronized by hydroxyurea, were also observed in distinct nuclear foci. The same pattern of localization has been observed during co-infection of cells with AA V and adeno-virus, and during H-I infection. Gel mobility shift assays show that a cellular protein from BFL cells synchronized in S-phase recognizes and binds the right terminus of BPV. The right terminus, in hairpin and double-stranded linear forms, is an effective competitor, indicating the complex is specific, and suggesting that sequence, rather than structure may be the recognition signal for this cellular protein. The left terminus of BPV, in the hairpin conformation is also an efficient competitor for complex formation. It has been shown that a cellular protein forms a complex with the left terminus and that the right terminus is an efficient competitor for complex formation. This data taken together suggests the same cellular factor may recognize both termini, and correlates with the observation that both can act as origins of replication, and could be recognized by similar proteins. The heterologous terminus of AAV in the hairpin conformation, is not an efficient competitor for complex formation between the right terminus of BPV and a BFL cell protein. The lack of competition may support the indication that the recognition signal is a specific sequence rather than a particular secondary structure. / Ph. D.

We analyze the Schrödinger equation i𝜖 ¬²â /â tΨ = H(𝜖)Ψ, where H(â ¬) = - f24 Î x + h(X) is the hamiltonian of a molecular system consisting of nuclei with masses of order 𝜖¬^-4 and electrons with masses of order 1. The Born-Oppenheimer approximation consists of the adiabatic approximation to the motion of electrons and the semiclassical approximation to the time evolution of nuclei. The quantum propagator associated with this Schrödinger Equation is exp(-itH(â ¬)/â ¬²). We use the Born-Oppenheimer method to find the leading order asymptotic expansion in â ¬ to exp(_it~(t:»Ψ, i.e., we find Ψ(t) such that: (1) We show that if H(𝜖) describes a diatomic Molecule with smooth short range potentials, then the estimate (1) is uniform in time; hence the leading order approximation to the wave operators can be constructed. We also comment on the generalization of our method to polyatomic molecules and to Coulomb systems. / Ph. D.

Autonomous parvoviruses, such as bovine parvovirus (BPV), need a factor present at the S-phase of the cell cycle for a productive infection, while dependent parvoviruses, the adenoassociated viruses (AAVs), require a helper virus to complete an infectious cycle. However, AAV can replicate autonomously in synchronized cells, suggesting that an S-phase factor substitutes for the helper virus. To investigate the nature of the cellular S-phase factor, we performed DNA retardation assays with uninfected nuclear extracts of S-phase cells, synchronized by hydroxyurea pretreatment, and radiolabeled parvoviral termini in their hairpinned conformation. We observed that proteins in HeLa cells, a tissue culture host for AAV, specifically interacted with the terminal sequences of this virus, which act as origins of replication (oris). These assays also showed specific binding between S-phase cellular proteins and termini (oris) of heterologous parvoviruses, for which the cells are not a natural host. For example, proteins from bovine fetal lung (BFL) cells, a tissue culture host for BPV, were able to bind to an AAV terminus and HeLa cell proteins interacted with both termini of the BPV genome. All DNA-protein complexes investigated appeared to be specific for S-phase synchronized cells. In order to begin to characterize the protein(s) involved in the complex formation, we performed SDS-PAGE electrophoresis of some retarded complexes. We report that a 54 kd protein was contained in the complex formed with the BPV left terminus and BFL cell extract. [Binding of BFL cell proteins to a BPV left terminus has been reported earlier]. Using a similar technique, we observed that two phosphoproteins of 55 and 90 kd were present in the retarded complex formed between a BPV left terminus and HeLa cell extract. An antibody directed against human p53, an anti-oncoprotein, was shown to compete binding of BFL cell extract and HeLa cell extract to the BPV left terminus. This antibody also competed the binding of HeLa cell extract to the AAV terminus. Our data suggest that proteins with similar characteristics, most probably among which is p53, are involved in the ori-binding complexes, possibly exerting a role as positive regulator of parvoviral replication. The secondary structure of the viral ends is remarkably conserved among parvoviruses. Of particular interest is the presence of mismatched/unpaired nucleotides, forming a bubble, in the stem of the left hairpin of almost all autonomous parvoviruses. To analyze the possible role of these unpaired/mismatched nucleotides in the BPV life cycle, two mutants clones lacking the bubble region were constructed and their replicative properties were analyzed after electroporation in permissive cells. Infectivity of the mutant clones was determined by three techniques: observation of cytopathic effect, detection of virally-coded proteins by indirect immunofluorescence, and transient DNA replication assays. We report that the mutant clone containing duplicate sequences of the (mismatched) nucleotides numbered 46 to 57 (BLOP) was defective for replication. The other bubbleless clone (BLOM), that contains duplicate sequences of the (mismatched) nucleotides 99 to 105, was able to replicate. The later clone produced monomer-length viral DNA at about 20% of the level of the infectious genomic clone of BPV, when electroporated as a linear excised sequence. This clone was infectious since it could be propagated by subsequent passage. Expression of viral structural proteins was seen by an indirect immunofluorescence assay using anti-capsid antibodies. Our results suggest that the bubble in the left hairpin of BPV is not required for the viral life cycle, but that specific sequences within the mismatched/unpaired region are necessary for viral replication. / Ph. D.

Cultural meaning has been a critical dimension of landscape design over several thousands of years. Recent literature submits that the strength of cultural meaning has waned over the last century. It is also suggested, however, that the landscape architect is in a unique position to strengthen the status of cultural and symbolic meaning in the landscape (Comer 1990). Before this can transpire, it is necessary for the professional landscape architect to have a clear understanding of what constitutes meaning in the landscape. Theory is discussed as purveying a structural foundation comprised of principals and axioms for understanding meaning. Semiotics or semiology, the science of signs and symbols, offers one systematic approach for analyzing and understanding cultural meaning. This approach, executed extensively in a number of cultural disciplines, has no recognized foundation in 'the discipline of landscape architecture. The fundamental aspect of semiotics is the sign or the sign model. The research reported herein begins the construction of a foundation for semiotics in the discipline of landscape architecture through the examination of three classic sign models as they apply to a contemporary landscape. The Vietnam Veterans' Memorial in Washington D.C. is analyzed in light of the sign models of Sassure and Peirce and the glossematic model of Hjelmslev. Each model is applied to the individual design aspects of 'the memorial in an attempt to understand the cultural meaning embodied in the monument. Based on the criteria, depth of analysis and clarity of language, the assets and liabilities of each model is determined through both an individual analysis and a comparative analysis. / Master of Landscape Architecture

Heat transfer in cylinder spaces is important to the performance of many reciprocating energy conversion machines, such as gas compressors and Stirling machines. Work over the past 10 years has shown that heat transfer driven by oscillating pressure differs from steady state heat transfer in magnitude and in phase; in-cylinder heat transfer under this oscillating condition can be out of phase with the temperature difference. For studies with closed piston-cylinder gas springs, this heat transfer phase shift has been successfully predicted with the use of a complex Nusselt number; since a complex number has both a magnitude and a phase, a complex Nusselt number can describe the phase shift between temperature and heat transfer. Quasi-steady heat transfer models, such as Newton's Law of Cooling, do not predict this phase shift. This project studied the problem of in-cylinder heat transfer with inflow-produced turbulence. Initial tests were conducted without the generated turbulence; this enabled the researchers to compare the results of this apparatus to previous work. Then, an orifice plate was added to the apparatus to generate simulated inflow-produced turbulence. The tests from this configuration were compared to the previous set, without the turbulence, to see how inflow-produced turbulence affected heat transfer and the heat transfer related cyclic lost work. The complex Nusselt number, which had been used in previous studies to model non-turbulent in-cylinder heat transfer, was applied to the turbulent data as well. The tests conducted without generated turbulence (one space experiments) matched previous results and also extended their range to lower volume ratios and higher oscillating speeds. These tests also demonstrated that an analytical heat transfer model based on low volume ratios (approaching 1.0) was valid over the range from 1 to 2. The tests conducted with the generated turbulence (two space experiments) were compared against the results from the one space experiments. These results indicated that the in-cylinder heat transfer was increased due to the generated turbulence. The magnitude of the complex Nusselt number compared favorably to an analytical model of in-cylinder heat transfer with inflow-produced turbulence. / Master of Science

Biomechanical models are used in many situations to help understand the risks associated with performing different work tasks. A necessary input to most biomechanical models is the body posture of the worker. Measuring posture has proven to be a difficult and time-consuming process. The research reported in this thesis investigated if a posture can be predicted instead of measured. The posture prediction model employs a whole-body sagittal plane representation of the worker with five links using inverse kinematic procedures to calculate the postures. The model chooses a posture by optimizing an objective function using a nonlinear programming search. Three separate models have been formulated to predict the postures of 16 subjects humans performing four static sagittal lifting tasks. Each model uses a different objective function or criterion defined relative to the torques on the human joints. These criteria are labeled as Total Torque, Percent Strength, and Balance. The influence of gender, hand position, and criteria on the prediction accuracy were investigated. The results showed that there was less postural variability for higher hand positions compared to lower hand positions. For lower hand positions there were two distinct types of postures chosen by subjects which implies that there are two different types of criteria being used by subjects at these hand positions. Student t tests, which investigated the accuracy of the predictions, showed that all of the prediction errors were significantly greater than zero at α=0.05. A mixed factor, repeated measures ANOVA investigating the prediction error showed that the Total Torque criterion was more accurate than the two other criteria. / Master of Science

Computers are being used in interior design for space planning, drafting, and modeling. Advances in technology have made it possible to create graphic renderings and animations which enable designers and clients to “walk through” the designed space long before its construction. In kitchen showrooms this technology can be used as a marketing device to generate numerous three-dimensional computer models of complete kitchen setups, each capable of displaying all the possible combinations of styles and finishes available. The purpose of this study was to test the communication effectiveness of three-dimensional computer-generated models in presenting design ideas and alternatives to a client. Three forms of kitchen design presentations were compared: Line Drawings, an actual Showroom Display, and three-dimensional Computer Model. A sample of 32 residents from the town of Blacksburg, Virginia were shown the three presentations and scored each one for its efficiency of communication of specific design concepts. Their reactions to the use of computer models as presentation media were also obtained. ANOVAs and Chi Square tests were used to analyze the data. The Showroom Display was the best communicator of space and design ideas and the, Computer Model was most effective in presenting color and finish alternatives. In conclusion, the Computer Models were found to be an effective and acceptable means of kitchen design presentation. Although they cannot replace Showroom Displays, Computer Models can be used effectively and economically as an enhancement to showroom displays and can facilitate reduction of the number of displays required for effective marketing in a showroom. / Master of Science