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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.
151

A study of the rheology, stability and pore blocking ability of non-aqueous colloidal gas aphron drilling fluids

Shivhare, Shishir Unknown Date
No description available.
152

Dawson Trotman's Personal Spiritual Disciplines as the Foundation for His Great Commission Ministry

Reynolds, Jeffrey Paul 31 March 2015 (has links)
DAWSON TROTMAN'S PERSONAL SPIRITUAL DISCIPLINES AS THE FOUNDATION FOR HIS GREAT COMMISSION MINISTRY Jeffrey Paul Reynolds, Ph.D. The Southern Baptist Theological Seminary, 2014 Chair: Dr. Timothy K. Beougher This dissertation argues that Dawson Trotman's personal spiritual disciplines served as the foundation of his Great Commission ministry. Chapter 1 defines important terms and states the case for researching Dawson Trotman's views on the subject. Chapter 2 presents a biographical sketch of Dawson Trotman's life, giving particular attention to his understanding of Great Commission ministry with emphasis on his understanding of the gospel and of the process of discipleship. Chapter 3 explores Trotman's personal spiritual disciplines and the bases upon which he developed his understanding of such disciplines. Attention is given to the scriptural sources from which he derived his intensive regimen of regularly practiced personal spiritual disciplines and other sources that influenced his thinking in these disciplines. Furthermore, this chapter examines Trotman's core theological beliefs regarding his personal spiritual disciplines and the methods he employed in practicing them. Chapter 4 chronicles Trotman's Great Commission ministry both in terms of its history and the vision Trotman proposed not long before his untimely death. This chapter concludes with an analysis of Trotman's understanding spiritual reproduction as the cornerstone of his Great Commission ministry and legacy. Chapter 5 bridges the gap between Trotman's intense regimen of personal spiritual disciplines and his Great Commission ministry. Specifically, this chapter illustrates how Trotman's personal spiritual disciplines provided the foundation, motivation, and urgency for his disciple-making ministry, and it shows that Trotman felt that his personal spiritual disciplines also provided for the effectiveness of his Great Commission ministry. Chapter 6 summarizes the research, presents conclusions, and offers some insight as to how Trotman can and should inform contemporary Christians as they seek to obey Christ's Great Commission.
153

Triggered and spontaneous star formation in the W3 giant molecular cloud

Allsopp, James January 2012 (has links)
The thesis goes on to extend the work of Bretherton (2003) and Moore et al. (2007) on the W3 Giant Molecular Cloud, by performing NH3 follow up of a sample of the cores discovered in the 850um SCUBA map and observing the whole cloud in 13CO(J=1-0) and C18O(J=1-0). - The NH3(1,1) and NH3(2,2) observations of the SCUBA cores used the fact that NH3 only traces the densest regions of the cloud, and hence can be used to find the temperature and kinematics of the cores themselves. This was used to test if the individual cores were virially bound, and from this find if cores in the more densely star-forming region of the cloud (High-Density Layer, HDL) were more likely to be bound than those in the Low-Density Layer (LDL). There are a mixture of virially bound and unbound cores in both the HDL and the LDL but no statistical difference in ratio of these between the two regions. This has an important bearing on models of environmentally-dependent star-formation, which divide into two categories; those, such as Collect and Collapse (Dale et al., 2007), which state that external pressures create dense structure, and those such as Radiatively- Driven Instability (RD I) (Bertoldi, 1989), which state that those external pressures cause dense structure to collapse. The evidence from this thesis favours models in which dense structure is created according to the Collect and Collapse scenario.
154

Three essays on sequential bargaining theory

Flamini, Francesca January 2002 (has links)
No description available.
155

A passion to exist : cultural entrepreneurship and the search for authenticity in Cornwall

Burton, Robert Edward January 2002 (has links)
No description available.
156

The regulation of polarised growth in the pathogenic form of Candida albicans

Stewart, Elaine January 1988 (has links)
The dimorphic yeast <i>Candida albicans</i> is capable of growth in a budding yeast form and in a mycelial form. Growing in the yeast form in the digestive and vaginal tracts it normally presents no problems to the host; however, when the dimorphic transition takes place and mycelial growth is initiated, symptoms of candidiasis manifest in the host tissues. This thesis studies the control of the dimorphic response and investigates some of the cellular changes which accompany it. Germ tube formation was induced in a defined amino acids/salts medium. Temperature, pH and culture density were critical factors in stimulating the dimorphic response. Different percentages of term tube formation were recorded for eight different strains of <i>C. albicans</i>. Each strain also acidified the growth medium to a different extent; this was correlated to the extent of filamentation of each strain. Internal pH changes were monitored using the weak and technique and <sup>31</sup>P nuclear magnetic resonance spectroscopy during bud and germ tube formation. In mycelial cells there was an initial increase in internal pH from 6.8 to around 8.0, followed by a gradual decrease to neutrality at the actual time of germ tube emergence. Cells in the budding form of growth did not exhibit such a marked increase in cytoplasmic alkalinisation. Mutant strains which were unable to produce germ tubes did not show cytoplasmic alkalinisation under conditions which would normally promote mycelial growth. Activation of the plasmamembrane ATPase may account for this increase in internal pH since diethylstilboestrol inhibited cytoplasmic alkalinisation and germ tube formation without affecting cell viability. Weak bases induced artificially, a rise in internal pH which was accompanied by germ tube formation. Potassium ions were found to enter cells as protons were expelled at the initiation of mycelial growth. Lactic acid prevented any rise in internal pH during germ tube formation. It also collapsed the ΔpH of the cells preventing growth by bud or germ tube formation. This may relate to the observation that endogenous <i>Lactobacilli</i> compete with <i>C. albicans</i> in the vagina and may explain why topically applied live yoghurt cultures soothe vaginal candidiasis. Transport of methionine was found not to be significantly different in cells induced to the budding or mycelial form. Transport or arginine and glutamate was induced by growing cells in the presence of these amino acids. The amino acid pool levels changed during the dimorphic process in <i>C. albicans</i>. A rapid increase in the pool level was shown within the first hour of both bud and hyphal growth followed by a gradual decrease. Little or no evidence was found in support of the hypothesis that the formation of hyphae is a response to nutrient starvation.
157

The matrices and rims of unequilibrated chondrites : Origins, metamorphism and alteration

Alexander, C. M. O'D. January 1987 (has links)
No description available.
158

Ring expansion reaction via homolytic pathways

Robertson, Jeremy January 1990 (has links)
The preparation of carbocyclic medium rings by two electron processes is reviewed with particular reference to the synthesis of natural products. The formation of medium rings by oxidative and homolytic methods is also reviewed. The synthesis and behaviour of both cis- and tran- ring expansion precursors is described. The 1,4-addition of tributylstannyl lithium to a range of cyclic α,β-unsaturated ketones was performed and procedures found whereby the so-formed enolates could be alkylated with a variety of electrophiles. Using these procedures a range of trans- ring expansion precursors were obtained in moderate to good yield. By the 1,4-addition of tributylstannyl lithium to 2-(ω-phenylselenoalkyl)-cyclohexenones, followed by enolate quenching with either water or methyl iodide, a range of cis- ring expansion precursors were produced. Homolytic ring expansion by either one, three, or four carbon atoms was shown to be possible, producing, respectively, seven, nine, or ten membered functionalised cycloalkenones in high yield except in cases where intramolecular reductive elimination was also possible. Attempts to extend this methodology to the synthesis of exomethylene cycloalkanones is described. The 3-tributylstannyl-3-(ω-phenylselenoalkyl)-cyclohex-2-enone precursors were found not to be successful substrates for ring expansion. The regiospecific alkylation of 2-(tributylstannylmethyl)-cyclohexanone with l-chloro-4-iodo-butane, followed by conversion of the chloride moiety to iodide led to a precursor which, on exposure to homolysis conditions, fragmented to produce the desired exomethylene cyclodecanone in high yield. Work directed towards the synthesis of medium ring cycloalkynones is described. Procedures were developed whereby 2-alkylated cyclohexan-l,3-dione derivatives could be obtained cleanly and in excellent yield on a large scale. The conversion of these derivatives to potential cycloalkynone precursors is described. It is shown that the products obtained after exposure of these precursors to homolysis conditions could, in principle, be derived from the putative cycloalkynones and mechanisms are suggested to explain the formation of these compounds. The homolytic ring expansion reaction was also performed on a substrate possessing an acyl radical precursor in the hope that a medium ring 1,2-dione would be produced. The synthesis of this substrate and its behaviour towards ring expansion is described. It is shown that, again, radical reaction was successful (to the medium ring dione) however subsequent reactions of this product led to the isolation and characterisation of a number of compounds . Attempts to extend this methodology to the synthesis of the natural products curdione and neocurdione is also described. Model reactions with 2,6-dimethylcyclohex-2-enone as the 1,4-addition precursor and 1,4-di-iodobutane as the electrophile led to a ring expansion substrate which fragmented to two ring contracted isomeric compounds in addition to the ring expanded material. Approaches to the preparation of suitable electrophiles for the natural product synthesis are described and their proposed use in subsequent conversion to curdione and neocurdione given.
159

Filament structure and phosphatase activity in the Rivulariaceae

Grainger, Stewart L. J. January 1989 (has links)
A study was carried out on phosphatase activity, phosphate uptake and its relationship to hair formation in the Rivulariaceae. The Rivulariaceae was chosen as it is a widespread taxon, where hair formation is a common occurrence, and previous studies indicated that they originate from environments where a large proportion of the phosphorus (P) is present as organic P. It seems possible that hair-forming Rivulariaceae are especially well adapted to utilize organic P. Initially 51 axenic cyanobacterial strains, from 10 genera, were screened for yields using organic P sources and for cell-bound and extracellular phosphomonoesterase (PMEase) and phosphodiesterase (PDEase) activities. All strains exhibited detectable inducible PMEase activities, and highest cell-bound PMEase activities were in hair-forming Rivulariaceae. Synechococcus had significantly low cell-bound phosphatase activities and five strains were unable to hydrolyze phytic acid. PDEase activities were lower compared to PMEase activities in all strains. Strains isolated from deepwater rice habitats had significantly higher levels of PDEase activity. In the three Calothrix strains tested, Calothrix 202, 550 and 603, inducible phosphatase activities were similar whether the P source was inorganic or organic. PMEase synthesis in these strains began when cellular P (% dry wt) values were in the range 0.60 - 1.0%. Differences in the influence of environmental variables on cell-bound and extracellular PMEase activities in hair-forming Calothrix 550 were slight, suggesting that PMEases in the two fractions had a common origin. Of the eleven ions tested Ca had the most pronounced stimulatory effect on PMEase activity. Localization of enzyme activity in Calothrix 550 suggested that the enzyme was bound to a surface. Partial purification of an extracellular PMEase fraction detected four bands of PMEase activity on a non-denaturing polyacrylamide gel. Three of the four bands were associated with carbohydrate and the bands were not extractable by mechanical means. Localization of PMEase activity in hair-forming strains by azo dye (naphthol AS-MX) and 5-bromo-4-chloro-3-indolyl phosphate (BCIP) showed that PMEase activity was associated with hair cells. Phosphate uptake experiments with Calothrix 253 and 550 suggested that uptake at high external phosphate concentrations was located in hair cells. NaCl, above 67.5 mM, inhibited hair formation and subsequently phosphatase activity in Calothrix 253 and 690. Addition of mannitol or sorbitol had no effect on hair formation, suggesting inhibition of hair formation was not an osmotic effect. Removal of P-deficient cultures from saline to freshwater media led to a marked synchronization of hair formation (in 90% of trichomes) and increase in cell-bound PMEase activity. Localization of cell-bound PMEase activity by light microscopy, using naphthol AS-MX, detected activity in the hair cells.
160

Imaging polarimetry of cometary nebulae

Semple, Dominic Peter January 1991 (has links)
In this work a review of many of the current theories of star formation as it is understood today is presented. New polarimetric observations of three cometary nebulae, RMon/NGC2261, RCr A/NGC6729 and the Chamaeleon Infrared Nebula are presented and discussed. It is shown how previous polarimetric measurements of the illuminating source of Hubble's variable nebula (NGC2261) have often produced results which increase in error with increasing wavelength. The reason for this is that previous authors have used an aperture size for measurements of R Mon which includes effects of a highly polarized feature ~ 5" north of RMon. Though this phenomenon has been seen before by other observers, its effect on polarimetric measurements of R Mon has not been recognised before despite tests to check for this. The data presented here agree with the interpretation that this feature is the northern-lobe of a mini-bipolar nebula, and it is further suggested that this is a manifestation of episodic mass outflow from R Mon. Previous explanations for the polarization of R Mon and RCr A cannot explain the rapid change in polarization and position angle that these young stellar objects are seen to undergo. Models of these objects which assume that they appear as polarized sources are used to explain the polarizations and are discussed. These models are not only able to produce the level of polarization seen at the source, but they are also currently the best models for explaining the rapid changes in polarization that are observed. A jet-like feature is seen to the south-west of the main nebulosity in the Chamaeleon IRN for the first time in observations presented in this thesis. A similar jet seen emerging from RCr A has been explained as being an emission feature collimated by an inner-circumstellar disc by previous authors. Evidence presented in this work for the jets seen emanating from both RCr A and the Chamaeleon IRN, suggests that these features are merely the preferentially illuminated rims of one of the outflow cavities, seen mainly by reflection of light from the source. Further evidence is provided to show that NGC2261 and NGC6729 are illuminated by RMon and RCr A respectively. In the case of the Chamaeleon IRN new evidence is provided to show that the nebula is illuminated by a heavily obscured infrared source located midway between the two outflow cavities.

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