The Chronic Pain Center (CPC) in Saskatoon offers a multidisciplinary treatment program whose goals are to facilitate improved coping skills, function and well-being, and to promote self-reliant lifestyles. They have documented a statistically significant improvement on several measures of physical and social functioning at the completion of the six week program, but to date have no formal evaluation of the long term effects.<p/> The purpose of this study was to re-evaluate the CPC clients (treatment group) at least one year following their completion of the treatment program to determine if they had maintained those improvements and also to compare them to the group of clients (control group) who underwent initial multidisciplinary assessment at the Centre, but did not attend the six week treatment program. Evaluation by mail out questionnaires assessed several important aspects of chronic pain. A 34% response rate resulted in 142 participants for this study.<p/> Data analyses involved a multi-stage process of univariate, bivariate and multivariate analyses. For the first goal, evaluating changes in the treatment group over time, the outcome variables considered had been administered at three points in time: admission to the CPC program, discharge from the six week program, and at study follow-up. For the second goal, the treatment and control groups were compared at one point in time; the study follow-up.<p/> The study demonstrated that the scores on all outcome variables used in the follow-up study improved significantly from the time of assessment to the time of discharge for the clients who attended the CPC treatment program. These improvements declined over time, but remained significantly improved from the admission scores. (Wilks Ë=.501, F(1,48)=4.788, p=.000) However, the study was unable to demonstrate any significant differences between the treatment and control groups on any of the outcome measures at the time of the study follow-up.(Wilks Ë=.930, F (1,107) = 1.014, p=.430) There were several limitations to this study, including the use of a non-randomized control group and the method of recruitment, which may have introduced bias into the study and affected the ability to effectively explain this finding.<p/>

This thesis examines vegetation community change at two temporal scales in the Piedmont of North Carolina. Using long-term plots in the Duke Forest, I examine decadal-scale changes in community composition of the forest understory and shed light on the potential drivers of that change. Using historical data from colonial survey records, I study presettlement forest communities of the Piedmont and attempt to reconstruct Piedmont forests as they may have been in the time before European arrival. The pattern of successional change in southeastern United States Piedmont forests has been assumed from chronosequence studies over the last half century. However, these assumptions for forest understory herb-layer populations and communities have not been tested using long term data sets. Using permanently marked plots in the Duke Forest (Durham, NC, USA) re-censused after a 23 year time step, species richness and community changes at 25m2 and 1000m2 scales are examined. I look at changes across life forms and examine these changes in relation to measured stand and environmental factors. Although total species richness stayed relatively constant through the 23 year step, herb richness declined with a concomitant increase in woody richness. Plot composition change was remarkably consistent and this change was not correlated to any measured stand or environmental factors. These community-level changes are consistent with previously reported changes in the understories of hardwood dominated stands in the Duke Forest, suggesting that landscape scale drivers may be more important than within-stand successional processes in patterning herbaceous communities at this time. Combined with growing evidence from other studies, this work indicates that forests in the temperate region may be experiencing changes different from those predicted by successional chronosequence studies. It indicates that one of the primary drivers of this change is the explosive growth of deer populations in the last two decades. Witness trees recorded in historical surveys have been used to reconstruct presettlement vegetation in many parts of North America, leading to a better understanding of vegetation patterns before the effects of Europeans. For some parts of North America, Government Land Office records make the process of reconstructing vegetation patterns easier - thus more is known about these areas. Because of the unique and unplanned nature of settlement in the southeastern U.S., less is known about the presettlement vegetation in this area of the country. Using a reconstructed cadastral map of a section of the North Carolina Piedmont, I was able to plot the positions of trees on the historical landscape. These data were then used to understand and reconstruct the composition of presettlement forests. Although the vegetation of some areas of the Piedmont is similar to what was expected, I find significant differences with the expected presettlement composition. In particular, pine species were common in some areas and rare in others, indicating that different disturbance regimes were active on the landscape. / Dissertation

Photonic crystal (PC) technology potentially offers lossless control of light propagation at a size scale near the order of the wavelength of light. The advantages and benefits of using such a technology in commercial devices are staggering. Yet, the commercial development of PC structures has been slow. Challenges associated with the repeatable fabrication and testing of structures has been identified as one cause of the slow development pace. To address these challenges, a development methodology that utilizes PC structures operating in the long-wavelength infrared is presented. One-dimensional PC structures, consisting of alternating regions of silicon and air are fabricated and characterized by measuring the transmittance or reflectance of the structure over the wavelength range from 5 쭠to 15 쭮 For the measurements, a model of the focused infrared beam is developed, tested and employed to characterize the structures. A novel measurement method, enabling the calculation of the single-angle plane-wave transmittances and reflectances from composite, multiple-angle transmittance and reflectance measurements, is formulated, tested and applied to PC structures. A new spectral characterization tool using a discretely tunable carbon-dioxide laser is presented and demonstrated. A measurement apparatus employing an FTIR microspectroscopy system is developed and measurements are recorded for the single-angle plane-wave characterization method. Single-angle plane-wave transmittances and reflectances calculated from composite multiple-angle measurements are shown to be in excellent agreement with theory. The results of this research are analyzed to identify the advantages and limitations of the long-wavelength infrared method.

A long period fiber grating (LPFG) is formed by inducing the periodic refractive index variation along a fiber. A lot of work has been done to fabricate the LPFGs in the photonic crystal fibers (PCFs) to function as all-fiber band-rejection filters, interferometers, and sensing applications. In this thesis, we propose a novel LPFG based on the gel-filled PCF. The PCF filled with the UV gel was exposed to the high-intensity UV light through the mask. The periodic index variation is formed along the fiber in the cladding region, resulting in the LPFG. By measuring the propagation losses of our LPFG, three spectral dips in the transmission bands are observed at 872 nm, 1309 nm, and 1418 nm as the grating period is 600 £gm, which indicates the mode coupling from the fundamental core mode to the higher order modes (HOMs) of the gel-filled PCFs. By using a full-vector finite-difference frequency-domain (FDFD) method, we numerically calculate the phase match condition for our LPFGs. The calculated resonant wavelengths are 875 nm, 1319 nm, and 1415 nm. Very good agreement between the measured resonant wavelengths and the numerical results is obtained. We also fabricate the selectively gel-filled LPFGs to reduce the propagation losses by utilizing a simple selectively blocking technique. In addition, we measure and discuss the sensing sensitivities of the UV-induced LPFGs, including the temperature, strain, curvature, torsion, and surrounding refractive index (SRI) sensitivities. The measured sensitivity to temperature is 1.7 nm/¢XC from 25 ¢XC to 45 ¢XC. As the surrounding refractive index is increased to 1.377, the dip position has a maximum shift of 2 nm. Compared with other LPFGs, the UV-induced LPFGs are more insensitive to bending and strain due to the complete cladding structure. This could benefit the stability of the temperature sensors, based on our UV-induced LPFGs.

In this thesis, a PEMFC stack, which can be self-humidification of passive portable hydrogen fuel cell, will be developed. The stack is developed for portable applications, so the structure of the stack is simplified as possible as we can. As the cathode directly exposed under the atmosphere, so in a long time, the membrane easily lead to excessive evaporation of water, so that performance degradation. The traditional humidifier is more complex applications are not suitable for portable, so this thesis stack developed by the use of cotton capillarity, the water from the tanks transferred to the membrane, and then by cotton and a good touch to the membrane humidifier effect, this structure without an increase in large equipment, in line with the principles of portability. The PEMFC stack is made with carbon fiber bunches for current collectors and two 8-cell banded-type MEAs, the stack can develop a high voltage by serially connecting outside of the reaction chamber. 16-cell in series when the current density is greater than 110mA/cm2, use humidification to avoid long time operation, due to water cause a voltage drop. Humidification is not only to help transfer of hydrogen ions, and the role of a cooling stack, the cells temperature is too high will not cause transpiration rate of speed. Current density greater than 250mA/cm2, although humidity can still be effective, but insufficient humidification single cotton, one hour after, the voltage drop of about 20% longer cell performance, such as humidity will be no more have a more significant decline phenomenon, more cotton or additional external humidification humidifier can maintain a long-time stable operation. Therefore, the performance of the cells in order to avoid a recession, should pay attention to in a long time when working conditions and operating range.

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OFDM-based WLAN systems are originally used for nearly static environment. But in the trend of user-convenience, if we want to support mobility, the most important issue is the Doppler effect caused by the object velocity. We investigate how the Doppler effect, signal-to-noise ratio (SNR) and imperfect estimation of channel impulse response (CIR) and the maximum Doppler shift fd influence the final bit error rate (BER) under the simulation environment, modified WLAN 802.11a specification. For these effects, we give some simulation results and conclusions. If CIR and df are known with the same number of multipath, we can see some phenomenon. First, the BER is dominated by AWGN noise. Second, under the same channel delay spread, the higher the object velocity is, the more serious the BER is. Third, under the same the object velocity, the more serious the BER is. If CIR is known instead of fd, under the same error percentage of fd and the same number of multipath, the lesser the velocity is the lesser the BER curve changes. If fd is known instead of CIR with the same number of multipath, the longer the channel delay spread is, the more serious the BER is.

No description available.

When a privately-held firm goes public through an IPO ¡]initial public offering¡^, the ownership structure of the IPO firm would change due to external equity financing. The ownership structure is related to the firm performance with respect to the corporate finance theory. Therefore, we agree that the relationship between the ownership structure and IPO long-run performance is worth examining. With respect to the corporate control and agency theory, we investigate the effect of the increase of insider ownership on the performance of IPO firms. We show that the increase of board ownership deteriorates the long-run performance of IPO firms. However, the increase of the institutional ownership improves IPO long-run performance. Basically, the agency theory implies that there exists positive relations between the insider ownership and performance and between the institutional ownership and performance. However, the corporate control theory agrees that the higher the insider ownership, the poorer the performance of the firms. Therefore, our results show that the institutional ownership can mitigate the agency problem while the role of corporate control subsumes the agency problem with respect to the insider ownership.

ABSTRACT Prior relative studies document that the mean initial returns of IPOs is significantly positive. Yet, several researches find that the positive abnormal returns appear to be a short-run phenomenon, and the long-run performance of IPOs is poor even negative. Based on a sample of 151 Taiwan IPO firms issued form 1991 to 1996, this study employ the Fama-French three factors model to measure the expected returns of securities. Consistent with predictions, the empirical results show positive short-run returns and a negative long run returns. Meanwhile, there is a negative relationship between institutional ownership and the holding period abnormal returns aftermarket. The conclusion is consistent with the concerns of long-term profitability of institutional investors, as they used to buy low for the benefits of long-term profits. This study also examines the influential factors of institutional ownership. The findings indicate that both firm size and insiders are significantly positive related to institutional ownership. However, neither managerial ownership nor debt is related to institutional ownership. On the other hand, there is significantly negative relationship between stock dividend and institutional ownership, except the second year. At the initial and the first month, cash dividend is negative related to institutional ownership, and industry dummy variable (electronic industry or not) is positive related to institutional ownership. Besides, there is no relationship between cash dividend and institutional ownership, nor was there any relationship between industry dummy variable and institutional ownership. According to the findings, most institutional investors want to maintain the diversification and long-term profits of the portfolio investment.