2004 MU theses - Access restricted to UM
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Item Arachidonate 15-lipoxygenase and ubiquitin as potential fertility markers in boars(University of Missouri--Columbia, 2004) Lovercamp, Kyle W.; Safranski, Timothy Jon, 1965-; Sutovsky, Peter[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] This study was performed to determine whether using high power microscopic analysis and two putative biochemical fertility markers, 15-lipoxygenase (15-LOX) and ubiquitin (UBI), could be used to accurately evaluate boar semen quality. In this study, ejaculates (n=116) were collected from 18 Large White boars for eight months (April, August-February). Ejaculates were analyzed and the percentage of proximal CDs (PCD), distal CDs (DCD), distal midpiece reflex CDs (DMR) and other spermatozoa abnormalities (ABN). Further ejaculate analysis was performed by semi-quantitative western blotting with computerized densitometry using antibodies against 15-LOX and UBI. Fertility data including FR and TNB was collected from sows mated to the boars in the study. Correlation coefficient analysis found moderate, negative relationships between FRs and DCDs (-0.39, P<0.01) and DMRs (-0.24, P<0.05), but not PCDs. These data suggest that an accurate boar semen analysis can be achieved by improved microscopy and by the use of biochemical fertility markers.Item Multiuser TDMA channel estimation(University of Missouri--Columbia, 2004) Kane, Roma; Xiao, Chengshan[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Wireless communication systems require efficient utilization of the limited available spectrum. There are various methods in which division of spectrum between users have been done till date, including frequency division, time division, code division and hybrid combinations of these methods. Cellular architectures efficiently utilize the spectrum by reusing the same channel in spatially separated cells. However, frequency reuse introduces co-channel interference, which determines the data rate that can be supported by each channel. For increasing the capacity of the multiple access systems, over the past few years research has been done on the field of multiuser multiple access systems. For example, in the case of TDMA systems, more than one user is allowed to use the same slot, thereby increasing the capacity of the conventional TDMA system. Implementation of a multiuser system calls for using either of the two techniques for detecting the co-channel signals, interference cancellation or multiuser detection. Multiuser detection is jointly detecting all the co-channel signals, while in interference cancellation technique desired signal is detected and the other co-channel signals are considered as interference. Over the years, various methods have been proposed for detecting the signals at the receiver, however not much attention has been given to the area of channel estimation. Majority of the research done on the receiver side assumes perfect channel knowledge. In this thesis I have proposed a very computationally easy and efficient algorithm of joint channel estimation based on least squares. The channel for all the users is simultaneously estimated. For this pilot sequence of each user having appropriate auto and cross correlation properties are used. I have also implemented a multislot MMSE based channel estimation algorithm for Multiuser TDMA system, as a comparison basis for the proposed algorithm. The results for Mean Square Error show that the proposed algorithm gives acceptable results. Also a graph has been presented to compare between the two algorithms.Item Pilot symbol design for multiuser CDMA systems(University of Missouri--Columbia, 2004) Kalgaonkar, Kaustubh; Xiao, Chengshan[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Due to the development of advanced processor architecture and better fabrication technologies of chips mobile devices have shrinked in size and improved in processing power. These pocket devices are now able run data hungry applications like browsing internet capturing and transferring video and audio files. To keep up with these advances in the devices new efficient algorithms on physical layer have to be developed to increase the capacity of the system and improve the utilization of available bandwidth. Code Division Multiple Access system support the best data rate amongst all the existing multiple access technologies, the performance of CDMA is further improved by using Multiuser detection. Most of the research focus for Multiuser CDMA system has been on the detection and channel estimation algorithms. There is a ceiling to the improvement of system performance for any give estimation algorithm. To further improve the performance of the system, the pilot sequences have to be optimized.There are lots of algorithms available for the design of training sequences for single user systems; these pilots cannot be directly applied for multiuser system as they degrade the correlations of the PN sequences and consequently the system performance. The preexisting training sequence design algorithms based on LS estimates cannot be directly used for CDMA systems as these pilot sequences are very long and the search space for optimization becomes very large. The time domain (TD), frequency domain (FD) based approaches of pilot design are also unable to reduce the search space for optimization to a manageable size. A novel approach for design of multiuser pilot training sequences is proposed in this thesis; this method optimizes the existing training/pilot sequence to improve the channel estimation. It is further confirmed via simulation that performance of both the LS and MMSE algorithms improves.Item Serum resistance of an invasive nontypeable H. influenzae(University of Missouri--Columbia, 2004) Tsao, David L.; Smith, Arnold L.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Since the introduction of Haemophilus influenzae b polysaccharide-protein conjugate vaccines, the incidence of invasive H. influenzae disease dramatically decreased. Currently, invasive disease is caused by other capsular serotypes or strains lacking genes for capsule synthesis, and therefore nontypeable (NTHi). A common feature of invasive H. influenzae is the ability to replicate in human blood, due to resistance to the bactericidal acitivity of serum. Seeking to understand the mechanism of serum-resistance in an invasive NTHi (strain R2866) we studied the strains recovered from the blood of five-day-old rats. We hypothesized that there would be increased virulence and acentuated resistance to normal human serum (NHS) in passaged isolates. We found that the rat passaged strain caused more deaths in the infant rat model, invaded Chang cells better but became more susceptible to the bactericidal action of NHS. This phenotypic shift was associated with modification of the lipooligosaccharide (LOS): more gal-B(1-4)gln epitope was exposed, while less gal-a-(1-3) gal was reactive with the monoclonal antibody. GeneScan® analysis of tetrameric repeats in the R2866 and the passaged strain indicated that expression of a LOS glycosyltransferase was OFF in the rat isolates. We conclude that animal passage of an invasive NTHi selects for increased animal virulence through expression of alternative LOS structures.