Thesis (Ph. D.)--University of Missouri--Columbia, 1999. / "May 1999." Typescript. Vita. Includes bibliographical references (leaves 168-184). Also available on the Internet.

This thesis focuses on an under-researched area of tourism - individualised travel - by examining non-institutionalised solitary travellers. The purpose of the study is to discover precisely why non-institutionalised solitary travellers travel alone. In order to understand the travel behaviour and motivation of solitary travellers, they are contrasted with group tourists. To be able to tackle this research problem, Grounded Theory is chosen as the most appropriate approach, for the following reasons. First, Grounded Theory is a methodology which makes its greatest contribution in areas about which little is known. Second, its aim is to generate rather than to test theory. Based on the computer-assisted content analysis and interpretation of relatively neglected qualitative data obtained from interviews and diaries, sixteen socio-psychological justifications for solo travel are empirically identified. From these responses, a taxonomy of non-institutionalised solitary travellers is inductively constructed. It consists of two basic types. First, there are those who travel alone because they simply have no available travel companion, referred to as "solitary travellers by default". Second, there are those individuals who deliberately travel on their own, and who are regarded as "solitary travellers by choice". The elaboration of such a distinction is the primary contribution made by this research to tourism knowledge. A secondary contribution is realised by confronting the data on solitary travellers and group tourists with the extant literature on tourist typologies - an exercise that raises a number of issues about the mythical status of the former. As a result, an alternative taxonomy is generated that consists of two distinct types of tourists - individualistic and collectivistic. The individualistic tourist is someone for whom internal personal values. (e.g., sense of accomplishment) are the most important principles in life, who has motives stemming from ego-enhancement (e.g., personal development), and for whom travel means the investment of personal cultural capital. The collectivistic tourist, on the other hand, is someone who assigns greater priority to external personal values (e.g., sense of belonging), whose motives originate in the anomic conditions of society, and for whom travel is little more than a short break from routine.

Baroclinic tides result from the interaction of barotropic tides with topography in stratified oceans. They play an important role in driving deep ocean mixing. In this research, investigations of the dynamics of baroclinic tides and internal solitary waves (ISWs) in the northern South China Sea (SCS) are conducted, mainly by means of the Massachusetts Institute of Technology general circulation model (MITgcm). Firstly, simulations of internal wave generation at the Luzon Strait (LS) are carried out. By conducting three-dimensional (3D), high-resolution experiments, it was found that the generated wave field features a multi-modal structure: large, pronounced ISWs of first mode (amplitude ~120 m) and second mode (amplitude ~120 m) were reproduced. The two north-south aligned ridges in the LS contribute together to the generation of the second mode ISWs, whereas the easternmost ridge of the two is responsible for the first mode ISWs. It was found that multiple generation mechanisms of internal waves could occur in this region, and overall it belongs to a mixed lee wave regime. A specific type of short internal waves arose during the 3D simulation. These ride on a second mode ISW with similar phase speed, trailing a first mode ISW. The short waves possess wavelengths of ~1.5 km and amplitudes of ~20 m, and only show up in the upper layer up to a depth of ~500 m. Scrutiny of the generation process showed that these short waves appear in two distinct regions and are produced due to two mechanisms, namely, the disintegration of an inclined baroclinic bore near the LS, and the overtaking of a second mode ISW in the deep water by a faster first mode ISW. Robust evidence has been sought from satellite imagery and by solving the theoretical Taylor-Goldstein Equation to verify their existence. The effects of superposition of multiple tidal harmonics (diurnal and semidiurnal) on the resultant ISW generation were investigated. It was first found that, by analyzing historical observational data, the occurrence of ISWs in the far-field always follow strong semidiurnal barotropic tidal peaks in the LS, regardless of whether it is the maximum for the diurnal or total tidal strength. However, modelling results of MITgcm and a linear internal tide generation model demonstrate that the diurnal tidal harmonics modulate the arrival time and amplitude of the propagating ISWs. Specifically, it leads to the emergence of the so-called A and B type ISWs and an alternation and transition between the two. Secondly, the shoaling process of ISWs in the northern SCS slope-shelf area is investigated. A series of two-dimensional (2D) experiments are set up to study the shoaling of a large-amplitude second mode concave ISW over a linear slope that resembles the SCS slope. Modelling results show that a strong transformation of the wave profile starts to take place when the wave is approaching the shelf break. A convex type wave is born at the trailing edge of the incident wave and gradually disintegrates into a group of ISWs due to the steepening of the rear wave profile. The frontal face of the wave gets flatter when travelling on the slope, but forms a steep structure right above the shelf break. However, this steep structure shows no tendency to evolve into an ISW: instead, it gets increasingly flat again while evolving on the shelf. The trailing convex wave packet travels faster and merges with the frontal concave wave. Finally, a wave packet with rank-ordered convex ISWs moves forward steadily on the shelf. Energy transfer to the ambient modes is evident, as both first mode and higher modes are clearly seen during and after the shoaling process. First mode ISW evolution is studied too by performing 3D, high-resolution experiments over the wide northern SCS slope and shelf area. It was found that the wave profiles change drastically near the shelf break and the Dongsha Atoll. In agreement with satellite imagery, the wavefront of the leading ISW becomes more spatially oblique with respect to its original orientation as it progresses westward due to the inclination of the slope in the topography. Wave disintegration is prominent in the shallow water zone, and wave polarity reverses near the turning point (at the 130 m isobath), which is consistent with the predictions of weakly nonlinear theory. A series of 2D experiments were set up to inspect the effects of rotation on the shoaling ISW. The results indicate that under the rotation, upon reaching the continental shelf, one shoaling ISW could disintegrate into one ISW packet and one secondary solibore that contains a number of rank-ordered waves with much shorter wavelength than an ISW. The secondary solibore is very pronounced in the northern portion of the northern SCS slope and shelf, but could hardly be discerned in the southern portion, which is consistent with the outcome of 3D simulations.

Bees provide a vital pollination service to many important crops and wildflowers yet are experiencing population declines across European and North American agricultural landscapes. The conservation of bee communities on farmland is a priority of the UK agri-environment schemes, which support pollinators through the provision of natural and semi-natural habitat, foraging resources and nesting sites. Data are needed to evaluate the effectiveness of these interventions in supporting bee communities and to allow the refinement of effective, evidence-based policy. This thesis examines the effectiveness of agri-environment management, though the provision of natural habitat, foraging resources and nesting sites, in supporting solitary bees, an important group of pollinators of which there are 250 species in the UK. Cavity nesting solitary bees and wasps were surveyed on 19 farms situated across central southern England, ranging from farms under no agri-environment scheme, to farms showcasing higher-level agri-environment management. Data on bee and wasp communities was collected by deploying solitary bee nest boxes. These nest boxes are marketed widely as nesting resources for solitary bees and are provided to farmers as part of Higher Level agri-environment schemes. Over the course of the study, 4002 solitary bees and wasps, comprising 10 species, were recorded. Natural Habitat: A positive relationship was identified between the abundance and species richness of bees and wasps and the proportion of natural habitat across farms. The availability of natural habitat also had a positive influence on the structural stability of bee and wasp parasitism networks; a positive association was identified with network link density. Link density measures the mean number of links per species within a network. Higher measures of link density are believed to confer greater resilience to species loss as individuals have more flexibility to switch interaction partner, limiting the risk of a cascade of secondary species extinctions. This set of results is encouraging, suggesting that the natural habitat types being promoted are effective in supporting solitary bee and wasp communities. Foraging resources: Examination of bee foraging preferences, through next generation sequencing of brood cell pollen DNA, demonstrated that the agri-environment scheme sown wildflower mixes do not support the foraging requirements of solitary bees effectively. Of the 15 plants included currently in the wildflower mixes that were recorded as present on the study farms, pollen from only one species, Ranunculus acris, was used by the bees. Rosa canina was identified as the most popular forage plant. The leaves of this species are also a preferred nesting material for Megachile leafcutter bees, providing strong justification for the inclusion of R. canina within the selection of hedgerow plants encouraged by agri-environment schemes. Tripleurospermum inodorum and Trifolium repens were also identified as good candidates for inclusion in wildflower seed mixtures. Nesting sites: A strong positive relationship between the density of solitary bee nest boxes and the rate of brood cell parasitism was identified, indicating that a high local density of nest boxes may expose bee larvae to a higher risk of parasitism. An enhanced risk of larval mortality could counteract the benefit of additional nest site provision. No significant effect of nest box provision on nest box colonization was identified across these study sites, suggesting that their placement across landscapes to encourage more pollinators may be counter-productive. It would be prudent to advise, given the results of this study, for the provision of a small number of dispersed nest boxes, this might more accurately mimic the availability of nesting resources in nature and reduce the risk of enhanced parasitism rates.

Numerical simulation of wave behaviour in shallow and deep water is often a key aspect of ocean, coastal, and river hydrodynamic studies. This thesis derives nonlinear one- and two-dimensional level I Green-Naghdi (GN) equations that model the motions of free surface waves in shallow water over non-uniform bed topography. By assuming fitted velocity profiles through the depth, GN equations are simpler than Boussinesq equations, while retaining the wave dispersion property. Implicit matrix solvers are used to solve the spatially discretised 1D and 2D GN equations, with a 4th order Runge Kutta scheme used for time integration. To verify the developed numerical solvers of 1D GN equations, a series of simulations are undertaken for standard benchmark tests including sloshing in a tank and solitary wave propagation over a flat bed. In all cases, grid convergence tests were conducted. In the sloshing test, both numerical schemes and the analytical solution were in complete agreement for small-amplitude free surface motions. At larger values of initial sloshing amplitude, the nonlinear effects caused the free surface waves to steepen, and eventually the numerical simulations became unstable. This could be resolved in future using a shock-capturing scheme. Excellent agreement was achieved between the numerical predictions and analytical solution for solitary waves propagating. The 2D GN equation solver was then verified for the benchmark tests of Gaussian hump sloshing and solitary wave propagation in closed basin. The predicted free surface motions for Gaussian hump sloshing were in good agreement with linear Fourier analytical solutions for a certain initial period, after which nonlinear effects started to dominate the numerical solution. A reversibility check was undertaken. Nonlinear effects were investigated by increasing the amplitude of the hump, and applying harmonic separation (by comparison against slosh predictions for a corresponding Gaussian trough). It was found that the even harmonic components provided a useful indication of the nonlinear behaviour of the 2D GN equations. 2D GN simulations of a 0.6 m amplitude solitary wave propagation in 1 m deep water over a flat, horizontal bed confirmed that nonlinear interaction was correctly modelled, when the solitary wave hit a solid wall and its runup reached 2.36 m which was 0.36m more than the linear analytical solution and almost identical to a second order solution.

Children with language impairment (LI) are more likely to be socially withdrawn than their typically-developing peers. This withdrawal can lead to negative outcomes later in life. This study focuses on a subtype of withdrawal labeled as solitary-pretend play, which involves parallel play and solitary-dramatizing. The effectiveness of the Teacher Behavior Rating Scale (TBRS) to measure the construct of solitary-pretend play was considered in a group of 256 children. First, confirmatory factor analysis was used on the entire sample to assess the TBRS questions. The TBRS ratings of 128 children with LI and 128 typically developing peers were then compared, with group and gender as variables. The analyses revealed that the TBRS items intended to measure solitary-pretend play grouped together to measure a single construct. Additionally, significant differences were observed between the groups of children with LI and their typically-developing peers. There was also a significant difference between boys and girls. The interaction between these variables was not significant. These results demonstrated that the TBRS is a viable measure of solitary-pretend play in children and that children with LI are rated as demonstrating higher levels of solitary-pretend play that their typical peers. Boys were also rated as demonstrating more instances of solitary-pretend play compared to girls. This study suggests that the TBRS is an effective way to quickly identify instances of solitary-pretend play in children and that children with LI and boys are more likely to demonstrate instances of solitary-pretend play, which will lead to the needed referrals and interventions to help manage these behaviors. Further research is required to determine the extent to which the influence of group and age has on solitary-pretend play and the extent to which each of the subtypes of withdrawal relate one to another.

Over the last several decades, the use of solitary bees as an alternative to honey bees (Apis mellifera L.) for pollination of commercial crops has increased, in part as a response to ongoing problems faced by commercial honey bee populations. Two solitary bee species have exhibited great commercial potential: the blue orchard bee, Osmia lignaria Say, and the alfalfa leafcutting bee, Megachile rotundata Fabricius (Hymenoptera: Megachilidae). However, growth of O. lignaria and M. rotundata populations is limited in commercial systems, mainly due to low establishment of females at provided nesting sites, possibly due to mortality, dispersal, or other causes. Rough handling of pre-emergent bees may possibly contribute to post-emergence dispersal in O. lignaria. The current work addressed this hypothesis by using shaking as a proxy for rough handling. However, shaken bees did not establish fewer nests than unshaken bees. Therefore, commercial fruit growers using O. lignaria as pollinators should be able to remove cocoons from their nests as part of their management plan, without fear of increasing bee dispersal. When searching for a nest site, M. rotundata females are known to be attracted to previously used nest materials. The current work verified the attraction of M. rotundata females to old conspecific nests. It also sought to determine which nest components were most attractive to females. It was found that all components were equally attractive. It may be useful to establish these species' learning abilities in a laboratory setting. The current work attempted to design a conditioning protocol for solitary bees. Initially, a method utilizing the proboscis extension reflex was sought. However, O. lignaria and M. rotundata did not reflexively extend their proboscises upon antennal stimulation with sucrose solution. Therefore, another method of conditioning was implemented. Bees were conditioned to respond to floral odors in a feeding bioassay. Results are compared for both species, as well as for males and females. The research completed for this dissertation may provide helpful information for commercial managers of solitary bees seeking to decrease both bee dispersal and the incidence of disease and parasites.

Reflection of an obliquely incident solitary wave at a vertical wall is studied experimentally in the laboratory wave tank. Precision measurements of water-surface variations are achieved with the aid of laser-induced fluorescent (LIF) technique and detailed temporal and spatial features of the Mach reflection are captured. During the development stage of the reflection process, the stem wave is formed with the wave crest perpendicular to the wall; this stem wave is not in the form of a Korteweg-de Vries (KdV) soliton but a forced wave, trailing by a continuously broadening depression wave. Evolution of stem-wave amplification is in good agreement with the Kadomtsev-Petviashvili (KP) theory. The asymptotic characteristics and behaviors are also in agreement with the theory of Miles (1977b) except those in the neighborhood of the transition between the Mach reflection and the regular reflection. The maximum fourfold amplification of the stem wave at the transition predicted by Miles is not realized in the laboratory environment: the maximum amplification measured in the laboratory is 2.92, which is however in excellent agreement with the numerical results of Tanaka (1993). The present laboratory study is the first to sensibly analyze validation of the theory; note that substantial discrepancies exist from previous (both numerical and laboratory) experimental studies. Agreement between experiments and theory can be partially attributed to the large-distance measurements that the precision laboratory apparatus is capable of. More important, to compare the laboratory results with theory, the corrected interaction parameter is derived from proper interpretation of the theory in consideration of the finite incident wave angle. Our laboratory data indicate that the maximum stem wave can reach higher than the maximum solitary wave height. The wave breaking along the wall results in the substantial increase in wave height and slope away from the wall. Extending the foregoing study on the reflection of a single solitary wave at a vertical wall, laboratory and numerical experiments are performed on two co-propagating obliquely incident solitary waves with different amplitudes that are reflected at the wall. The larger wave catches up with the smaller wave; hence the two waves collide with the strong interaction. The resulting wave pattern near the wall is complex due to the interaction among the two incident solitons and the two reflected solitons. The numerical predictions of the KP theory are in good agreement with the experimental results. Another comparison of the KP theory with laboratory experiments is demonstrated for one of the exact soliton solutions of the KP equation by Chakravarty and Kodama (2009). This solution is called the T-type solution by Kodama. The theoretically predicted formation of the 'box'-shape wave pattern in the vicinity of two-soliton intersection is realized in the laboratory tank. The agreement between the laboratory observation and the KP theory is found better for the cases with the larger wave amplitude a and smaller oblique angle ψ (i.e. tan ψ/(√3a cos ψ) < 0.6). Subtle and unavoidable differences among the analytical KP solution, the setup of numerical calculation, and the laboratory condition are discussed. / Graduation date: 2013

As a solitary wave is usually used to characterize the behavior of a tsunami, a hydraulic experiment is set up for a detailed study of the associated celerity and particle trajectory. The size of the water tank of this experiment in this paper is 21m long, 0.5m width and 0.7m deep. Wave maker method used by Goring (1978) for simulating Solitary Waves is applied in the experiment of particle trajectories and mass transport. We also extend the particle trajectories theory to higher order that contains the non-linear terms. The method presented in this paper fixes the position of the camera, and the grid-point board is located in the center of the water tank, so that the particle and the two-dimensional grid surface coincide. Then, we analyze the particle trajectories within the grid with image processing techniques. This method not only save time of coordinate calibration, but also get a more accurate measurement. The water particle used in this paper has 1mm diameter, because it is difficult to locate the exact position of a large particle. Because of the small size in this experiment, we can get better results and the error is reduced. To compare with the experiment, the third-order Eulerian solution of Feton(1972) is transferred to the Lagrangian system in the present study to get the particle velocity. Then an integral with respect to time is used to obtain the trajectory. The accuracy of the theory is good, especially in the regime of small amplitude. For large wave amplitude in terms of the water depth, a higher order solution is suggested for the future study.

¡@¡@The research on collection or reflection of solitary waves mainly focus on numerical model and theoretical analytics, there are few study on experiment. due to the process on reaction of solitary waves are very short in times, and the waveform is also hardly to measure quantifiable. ¡@¡@The method present in this paper that we setup a high speed camera at a fixed position, and a grid-point board is located in the water tank and out of the tank after pictured, then we capture the process on reflection of solitary wave at a wall by high speed camera, so that the waveform and the grid surface coincide. finally, we analyze the waveform within the grid by using image techniques. ¡@¡@The results of this paper that present several important parameters in several relative wave height, such as maximal run-up, residual time, phase shift..et.al. the other hand, this paper compare the result of experiment with available evidences likes numerical model and theoretical analytics that found to be in quantitative agreement. ¡@¡@In addition, this paper also present the result of experiment that could compare with the new phenomenon "residual falling jet¡¨, it`s published by Chambarel.et.al (2009) numerical model.