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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

An evaluation of supported bus and community transport services in rural Scotland

Currie, Margaret Joan Barrie January 2009 (has links)
This study examines policies which provide support to rural bus services and the extent to which these policies meet the accessibility needs of rural communities in Scotland. In recent years, accessibility opportunities have improved for the vast majority of rural people because of increased ownership of the private car.  However, the minority of people who do not have access to a car can face considerable difficulties in accessing all opportunities and may consequently be socially excluded.  The Government wishes to promote modal shift from the car to public transport wherever possible in rural areas.  Policies which provide support to bus services represent a mobility approach to tackling rural accessibility needs. In this study, the methodology used is the ‘Accessibility Policy Assessment Tool’ (APAT), which is used to systematically assess the accessibility impact of policies through a mixed methods approach.  This approach is used to ascertain the ways in which bus support policies could delivery more effective accessibility impacts to rural communities, and is critiqued as part of the study.  The main results of the study were that there are particular characteristics of some policies which enabled them to be more effective at delivering accessibility benefits to some rural communities.  Specifically, those policies which were delivered in a bottom-up fashion allowed local accessibility needs to be better understood and the services put in place could be more responsive to these needs.  In conclusion, it is suggested that bus support policies delivered in a top-down fashion may not effectively be meeting accessibility needs, and thus tackling social exclusion, and that it appeared difficult for urban-delivered policies to meet the accessibility challenges present within rural communities.
212

Modeling bone marrow sub-structures at power-line frequencies

Chiu, Roanna Sum-Wan. 10 April 2008 (has links)
No description available.
213

THE CIRCUMGALACTIC MEDIUM OF SUBMILLIMETER GALAXIES. I. FIRST RESULTS FROM A RADIO-IDENTIFIED SAMPLE

Fu, Hai, Hennawi, J. F., Prochaska, J. X., Mutel, R., Casey, C., Cooray, A., Kereš, D., Zhang, Z.-Y., Clements, D., Isbell, J., Lang, C., McGinnis, D., Michałowski, M. J., Mooley, K., Perley, D., Stockton, A., Thompson, D. 15 November 2016 (has links)
We present the first results from an ongoing survey to characterize the circumgalactic medium (CGM) of massive high-redshift galaxies detected as submillimeter galaxies (SMGs). We constructed a parent sample of 163 SMGQSO pairs with separations less than similar to 36" by cross-matching far-infrared-selected galaxies from Herschel with spectroscopically confirmed QSOs. The Herschel sources were selected to match the properties of the SMGs. We determined the sub-arcsecond positions of six Herschel sources with the Very Large Array and obtained secure redshift identification for three of those with near-infrared spectroscopy. The QSO sightlines probe transverse proper distances of 112, 157, and 198. kpc at foreground redshifts of 2.043, 2.515, and 2.184, respectively, which are comparable to the virial radius of the similar to 10(13) M circle dot halos expected to host SMGs. High-quality absorption-line spectroscopy of the QSOs reveals systematically strong H I Ly alpha absorption around all three SMGs, with rest-frame equivalent widths of similar to 2-3 A. However, none of the three absorbers exhibit compelling evidence for optically thick H I gas or metal absorption, in contrast to the dominance of strong neutral absorbers in the CGM of luminous z similar to 2 QSOs. The low covering factor of optically thick H I gas around SMGs tentatively indicates that SMGs may not have as prominent cool gas reservoirs in their halos as the coeval QSOs and that they may inhabit less massive halos than previously thought.
214

THE PAN-STARRS1 DISTANT z > 5.6 QUASAR SURVEY: MORE THAN 100 QUASARS WITHIN THE FIRST GYR OF THE UNIVERSE

Bañados, E., Venemans, B. P., Decarli, R., Farina, E. P., Mazzucchelli, C., Walter, F., Fan, X., Stern, D., Schlafly, E., Chambers, K. C., Rix, H-W., Jiang, L., McGreer, I., Simcoe, R., Wang, F., Yang, J., Morganson, E., Rosa, G. De, Greiner, J., Baloković, M., Burgett, W. S., Cooper, T., Draper, P. W., Flewelling, H., Hodapp, K. W., Jun, H. D., Kaiser, N., Kudritzki, R.-P., Magnier, E. A., Metcalfe, N., Miller, D., Schindler, J.-T., Tonry, J. L., Wainscoat, R. J., Waters, C., Yang, Q. 14 November 2016 (has links)
Luminous quasars at z > 5.6 can be studied in detail with the current generation of telescopes and provide us with unique information on the first gigayear of the universe. Thus far, these studies have been statistically limited by the number of quasars known at these redshifts. Such quasars are rare, and therefore, wide-field surveys are required to identify them, and multiwavelength data are required to separate them efficiently from their main contaminants, the far more numerous cool dwarfs. In this paper, we update and extend the selection for the z similar to 6 quasars presented in Banados et al. (2014) using the Pan- STARRS1 (PS1) survey. We present the PS1 distant quasar sample, which currently consists of 124 quasars in the redshift range 5.6 less than or similar to z less than or similar to 6.7 that satisfy our selection criteria. Of these quasars, 77 have been discovered with PS1, and 63 of them are newly identified in this paper. We present the composite spectra of the PS1 distant quasar sample. This sample spans a factor of similar to 20 in luminosity and shows a variety of emission line properties. The number of quasars at z > 5.6 presented in this work almost doubles the previously known quasars at these redshifts, marking a transition phase from studies of individual sources to statistical studies of the high-redshift quasar population, which was impossible with earlier, smaller samples.
215

The genetics of miRNA and mRNA expression in human lymphoblastoid cell lines

Wills, Quintin Frank January 2012 (has links)
Human clinical genome-wide association studies (GWAS) have helped identify disease trait and pharmacogenomic loci without the need for biological under- standing. Molecular GWAS - associating genetic variation with traits such as gene expression - have been slow to fill the mechanistic gaps. While tissue specificity, lack of DNA resolution, and the need for better data integration are no dou bt important bottlenecks in molecular GWAS, there is also a very poor general understanding of which molecular phenotypes are important and how best to model them. Added to this is the clear need for a greater understanding of the strengths and weaknesses facing in vitro (and ex vivo) models as hypoth- esis generating and GWAS validation tools. The studies in this work focus on RNA expression in a popular human model: lymphoblastoid cell lines (LCLs). Chapters 2 and 3 examine microRNA (miRNA) and messenger RNA (mRNA) expression in a total of 300 genotyped human LCLs. The expression of only one miRNA could be associated with a nearby genetic variant. This result was observed in both the African and European samples studied, in a separate val- idation data set, and was technically validated with quantitative PCR. While limited genotype resolution and small sample sizes are likely to be important contributors to this low hit rate, the results strongly suggest experimental con- founders. Highly expressed miRNAs reflected the transformed nature of the cells, highly correlated miRNAs enriched for EBV and malaria associated tar- get mRNA genes, and several miRNAs that were differentially expressed be- tween the European and African samples suggested differential EBV transfer- mation. Chapter 4 presents a study on single cells from some of the same samples, to test the hypothesis that the lack of tissue spatial resolution is an important limiting factor in human genetic epidemiology. Experimental con- founders were also considered: sample growth was found to associate with the expression of several genes. Cell-to-cell gene correlations and distributions made it possible to propose how genes change their expression, functionally differ from each other, and are able to alter their behaviours without altered whole-tissue expression. The results suggest which type of genes are more likely to be susceptible to genetic effects, and propose promoter behaviours altered by genetic variants located near to 13 genes. From these whole-tissue and single cell results the broad conclusion is that, while LCLs are likely to be inappropriate for the study of miRNA genetics, their functional genomics at higher spatial resolution shows promise as a more mechanistic approach for the study of germline genetics.
216

A study of the variation in the equivalent widths of certain infra-red Fraunhofer lines across the solar disc

Pagel, Bernard Ephraim Julius January 1955 (has links)
No description available.
217

Error control with constrained codes

04 February 2014 (has links)
M.Ing.(Electrical and Electronic Engineering) / In the ideal communication system no noise is present and no errors will be made. However, in practice, communication is over noisy channels which cause errors in the information. There is thus a necessity for the control of these errors. Furthermore, several channels impose runlength or disparity constraints on the bit stream. Until recently, the error control on these channels was applied separately to imposing the input restrictions with constrained codes. Such a system leads to poor performance under certain conditions. and is more complex and expensive to apply than systems where the error control is an integral part of the constrained code or decoder. In this study, we firstly investigate the error multiplication phenomena of constrained codes. An algorithm is presented that minimizes the error propagation probabilities of memoryless decoders according to two criteria. Another algorithm is presented along with the first to calculate the resulting bit error probabilities. The second approach to the error control of constrained codes is the construction of combined error-correcting constrained finite-state machine codes. We investigate the known construction techniques and construct several new codes using extensions of the known techniques. These codes complement or improve on the known error-correcting constrained codes with regards to either complexity, rate or error-correcting capability. Furthermore, these codes have good error behaviour and favourable power spectral densities.
218

From Onlooker to Interpreter

Rinehart, Jeff 16 May 2008 (has links)
In my artwork, I incorporate narratives, which help me explore relationships and how they exist within the context of the formal imagery on the page. The idea of storytelling highly influences the way I approach and produce art. To hint at a story will entice the viewer to make connections and create a platform on which to further inspect the image. The lines in my work attempt to mimic the way stories and information can loop and intertwine to negate the personal, surround the personal or maybe just provide something that the viewer would have to weave his way through in order to create that relationship between the disparate layers. Through my work, I seek to divert the viewer's expression of an instinctual response, from one that would be expected to one that plays with the idea of the spectator transforming from onlooker to interpreter.
219

Expression patterns of immune associated genes in Euoniticellus intermedius and characterization of the embryonic cell line

Alaouna, Mohamed 01 February 2013 (has links)
As bacteria are becoming resistant to conventional antibiotics, researchers are looking for new ways to combat microbial infection. We have begun to adopt genetic and functional genomic approaches to define the molecular determinants of pathogen resistance in the dung beetle, Euoniticellus intermedius. This dung beetle survives microbe-rich environments such as dung. This ability makes it a potential model for the study of infectious agents and ecological damage. To date, E. intermedius has not been studied at the molecular level. In this study, a range of complimentary analytical techniques were used to characterize the E. intermedius embryonic cell line established in our laboratory. These techniques characterize morphology, growth characteristics, karyotype, isoenzyme patterns and embryonic development. Complete characterization of the E. intermedius cell line is essential for the cell banks and for the regulatory requirements in biopharmaceutical production. This study followed gene sequences and their comparisons for both adult and cell line to confirm that the E. intermedius (EISA08) cell line is originated from the embryonic E. intermedius dung beetle. cDNA was synthesized from mRNA isolated from E. intermedius adult beetles and cell line (EISA08) was sequenced using GS (FLX) technology by a commercial facility, Inqaba Biotechnical Industries (Pty) Ltd, South Africa. In addition to characterization of the cell line, two genes, namely hopscotch and ribosomal protein S9 (RpS9), were selected from the Flylab genome data base. The E. intermedius database is a web-based system for the genome and transcriptome of the dung beetle to evaluate the immune system of the dung beetle (http://Flylab.wits.ac.za/). hopscotch was selected because it is believed to be involved in the JAK-STAT signalling pathway for anti-viral response, embryonic development and cell growth. Rsp9 was chosen as a loading control because it is expected to be a housekeeping gene. The conserved molecular signalling pathway JAK-STAT is used by E. intermedius (as in other insects and humans) for immune defence and early embryonic development. The project followed hopscotch and Rsp9 gene expression in all the E. intermedius life cycle developing stages; adult, pupae, larvae, embryo, and cell line cell growth, life cycle developing stages and embryonic development has was monitored. E. intermedius embryonic development is described as short germ-band. E. intermedius embryogenesis is regarded as basal and is observed in most arthropods. The study revealed that E. intermedius hopscotch is over expressed in the early developing stages, embryo, larvae, and pupae and in the newly established cell line EISA08. The results from this study lead to the suggestion that E. intermedius JAK-STAT pathway is activated early and has an important role in embryonic development, cell proliferation and immune defence. Studies of E. intermedius could provide more insight into the properties and evolution of innate immunity and embryonic development.
220

A MATLAB based analysis tool for clearance and thermal violations in transmission power lines

Mabuza, Ndumiso Simon January 2016 (has links)
A research report submitted to the faculty of Engineering and the Built Environment, of the University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering Johannesburg 2014 / Clearances are an important aspect of High Voltage (HV) transmission line design, construction and maintenance. A software tool that combines clearance violation analysis and optimum loading operating conditions for power lines could save power utilities the capital cost of refurbishing transmission power lines that marginally exceed maximum power line clearance distances. This can be achieved by operating the power lines at an optimum amperage level for any given set of weather conditions. This research project proposes a low cost MATLAB® based software tool that detects clearance violations and determines operational limits on transmission power lines using prevalent weather conditions as well as the power line amperage. Various power lines around the states of Missouri and Illinois in the United States of America are analysed to test the viability and functionality of the software. In order to validate the accuracy of the program, the results obtained were compared to results from PLSCADD ®. Key Words: conductor, clearance, sag, software, temperature / MB2016

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