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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.
31

Structure of the Cape Fold Belt in the Ceres Syntaxis

De Beer, C. H 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 1989. / ENGLISH ABSTRACT: The Ceres Syntaxis comprises that part of the Cape Fold Belt Syntaxis that lies north of the Worcester Fault. Most of the area consists of folded Cape Supergroup (primarily Witteberg Group) rocks. Fold styles of all fold trends are essentially the same. However, different multilayer rheologies led to the development of either sinusoidal or kink-like fold geometries in different parts of the cover sequence. The character of Witteberg sediments led to the development of large megakink folds and peculiar fold zones in this part of the sequence. Fold trends in the Ceres Syntaxis vary between NW-SE, NE-SW and E-W. The southern part of the area is dominated by the NE-SW trend, with the NW-SE trend being only important in the west. Interference between these two trends only exists in the Witteberg Group, where it occurs as crossing linear fold zones and conjugate, intersecting kink folds . Cross-folding relationships in the north-eastern part of the Ceres Syntaxis indicate that the area had been affected by two contemporaneous, orthogonally opposed compressions that worked simultaneously in different parts of the multilayer. Differences in the magnitude of strain, or in the local timing of fold initiation, produced local refolding or transecting relationships. The microfabric of Witteberg sandstones suggests deformation under conditions of low temperature and pressure, as well as low strain rates. Some microfabrics also indicate that substantial buckle shortening occurred while the Middle and Upper Witteberg beds were still unlithified. Isotopic dating of Cedarberg shale from both main trends did not yield unequivocal results, mainly due to the deformatio~al intensity. The positioning of the Cape low Fold Belt Syntaxis was strongly influenced by basement tectonic grain and basin floor relief. The NW and NE fold trends formed on a heterogeneous basement that resolved the stress configuration into components which external . acted simultaneously towards the north-west and north-east. Ecca and Beaufort Group sedimentation patterns in the western Karoo corroborate the above findings. / AFRIKAANSE OPSOMMING: Die Ceres-sintaks beslaan daardie deel van die sintaks van die Kaapse Plooigordel wat noord van die Worcesterverskuiwing Ie. Die gebied bestaan grotendeels uit geplooide gesteentes van die Supergroep Kaap (hoofsaaklik Groep Witteberg). AIle plooirigtings openbaar dieselfde plooistyl. Reologiese verskille in'die rnultilaehet egter gelei tot die ontwikkeling van of sinusoidale ~f knikvorrnigeplooie in verskillende dele van die dekgesteentes. Die Wittebergsedirnente se aard het veroorsaak dat rnegaknikkeen eienaardige plooisones in hierdie deel van die opeenvolging ontstaan het. Plooirigtings in die Ceres-sintaks wissel tussen NW-SO, NO-SW en O-W. Die NO-SW plooirigting oorheers in die suidelike deel van die gebied, terwyl die NW-SO plooirigting eintlik net in. die weste belangrik is. Interferensie van hierdie twee.hoofrigtings korn slegs voor in die Groep Witteberg, waar dit as dwarssnydende lineere plooisones en snydende, konjugerende knikke aanwesig is. Onderlinge verhoudings tussen kruisplooie in die noordoostelike Ceres-sintaks, toon dat die gebied beinvloed is deur twee gelyktydige drukspannings wat reghoekig op rnekaar ingewerk het, sorntyds in effens verskillende dele van die rnultilaag.Verskille in die spanningsbedrag en tydsberekening het lokale herplooiing of dwarssnydende strukture veroorsaak. Die mikrornaaksel van die Wittebergsandsteen toon dat die vervorming onder lae temperatuur- en druktoestande, tesame met 'n lae vervorrningsternpo, plaasgevind het. Die rnaaksel toon ook aan dat heelwat buigplooiing plaasgevind het terwyl die Middel- en Bo-Witteberglae nog ongekonsolideer was. Isotopiese datering van Sederbergskalie afkornstigvan die twee hoofplooirigtings, het weens die lae vervormingsintensiteit swak resultate gelewer. Die posisie van die sintaks van die Kaapse Plooigordel, insluitende die van die Ceres-sintaks, is sterk' belnvioed deur die tektoniese grein en re~i~f van die vloergesteentes. Die heterogene vloer waarop die NW en NO plooie gevorrn het, het daartoe gelei dat die eksterne spanningsopset verdeel is in kornponentewat gelyktydig na die noordweste en noordooste gewerk het. Sedirnentasiepatrone in die Groepe Ecca en Beaufort ondersteun bostaande afleidings.
32

The Association of Subscapular and Triceps Skin-Fold Thickness with the Risk of Diabetes in African American, Hispanic, and Caucasian Adults

Porter III, Jake Johnson 07 December 2007 (has links)
JAKE J. PORTER III The association of subscapular and triceps skin-fold thickness with the risk of Diabetes in African American, Hispanic, and Caucasian Adults (Under the direction of IKE S. OKOSUN, Ph.D.) Background: Studies linking adiposity with chronic morbidity are often restricted to obesity defined by body mass index and/or waist circumference. Few studies have examined the relationship between adiposity defined using body habitus and chronic diseases. Objective: We examined the potential association of subscapular and triceps skin-fold thickness with the risk of diabetes in African American, Caucasian, and Hispanic American adults. Methods: Data (n=4,808) from The National Health and Nutrition Examination Survey were used. Multivariate logistic regression analysis was performed on each anthropometric measure. Statistical adjustments were made for several known covariates. Results: There were racial/ethnic differences in associations between subscapular and triceps skinfold thickness with type 2 diabetes. Conclusion: Skinfold thickness was associated with type 2 diabetes in White, Black and Hispanic Americans. Well designed public health strategies to enhance lifestyle modification programs to reduce weight gain may reduce aberrant fat distribution in these body regions and decreases in type 2 diabetes.
33

Dynamical modelling of the human larynx in phonation

Apostoli, Adam Graham January 2012 (has links)
Producing an accurate model of the human voice has been the goal of researchers for a very long time, but is extremely challenging due to the complexity surrounding the way in which the voice functions. One of the more complicated aspects of modelling the voice is the fluid dynamics of the airflow, by which the process of self-oscillation of the vocal folds is sustained. This airflow also provides the only means by which the ventricular bands (two vocal fold-like structures located a short distance above the vocal folds) are driven into self-oscillation. These have been found to play a significant role in various singing styles and in voice pathologies. This study considers the airflow and flow-structure interaction in an artificial up-scaled model of the human larynx, including self-oscillating vocal folds and fixed ventricular bands. As the majority of any significant fluid-structure interaction takes place between structures found within the larynx, this thesis is limited only to examining this component of the voice organ. Particle Image Velocimetry (PIV) has been used to produce full field measurements of the flow velocity for the jet emerging from the oscillating vocal folds. An important advance in this study is the ability to observe the glottal jet from the point at which it emerges from the vocal folds, thus permitting a more complete view of the overall jet geometry within the laryngeal ventricle than in previous work. Ensemble-averaged PIV results are presented for the experimental model at different phase steps, both with and without ventricular bands, to examine their impact on the dynamics of the human larynx and the glottal jet. Finally, the three-dimensional nature of the glottal jet is considered in order to further understand and test currently held assumptions about this aspect of the jet dynamics. This was achieved by undertaking PIV in a plane perpendicular to that already considered. It is shown that the ventricular bands have an impact on the flow separation point of the glottal jet and on the deflection of the jet centreline. Furthermore, the dynamics of the vocal folds alters when ventricular bands are present, but the glottal jet is found to exhibit similar three-dimensional behaviour whether or not ventricular bands are present.
34

Syntaxin-1A Inhibits the KATP Channel Through Interaction with Distinct Sites Along the Nucleotide-binding Folds of Sulfonylurea Receptor 1

Chang, Nathan 13 January 2010 (has links)
The KATP channel is a key regulator of the pancreatic β-cell, effectively linking metabolic status to electrical activity. Syntaxin-1A has been previously reported by our lab to both bind and inhibit the KATP channel via the nucleotide-binding folds (NBFs). The purpose of this thesis project was to elucidate the precise regions within the NBFs responsible for the Syn-1A- KATP interaction. In vitro binding assays revealed that Syn-1A associates with the Walker domains of both NBF1 and NBF2. Furthermore, site directed mutagenesis of the conserved lysine in Walker A of both NBFs abolishes Syn-1A affinity for this region. Electrophysiological recordings indicate that channel inhibition was mediated primarily through interaction with NBF1-Walker B and both Walkers of NBF2. Based on these results, we propose a model by which Syn-1A acts as an inhibitory clamp on the KATP channel, effectively buffering minor fluctuations in ATP/ADP concentration to prevent unnecessary channel activity.
35

Syntaxin-1A Inhibits the KATP Channel Through Interaction with Distinct Sites Along the Nucleotide-binding Folds of Sulfonylurea Receptor 1

Chang, Nathan 13 January 2010 (has links)
The KATP channel is a key regulator of the pancreatic β-cell, effectively linking metabolic status to electrical activity. Syntaxin-1A has been previously reported by our lab to both bind and inhibit the KATP channel via the nucleotide-binding folds (NBFs). The purpose of this thesis project was to elucidate the precise regions within the NBFs responsible for the Syn-1A- KATP interaction. In vitro binding assays revealed that Syn-1A associates with the Walker domains of both NBF1 and NBF2. Furthermore, site directed mutagenesis of the conserved lysine in Walker A of both NBFs abolishes Syn-1A affinity for this region. Electrophysiological recordings indicate that channel inhibition was mediated primarily through interaction with NBF1-Walker B and both Walkers of NBF2. Based on these results, we propose a model by which Syn-1A acts as an inhibitory clamp on the KATP channel, effectively buffering minor fluctuations in ATP/ADP concentration to prevent unnecessary channel activity.
36

Metamorphism and folding in the Mt. Lofty Ranges, South Australia, with particular reference to the Dawesley-Kanmantoo area

Fleming, Peter David January 1971 (has links)
2 v. : ill. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Minerology, 1972
37

The Grenville front foreland fold-and-thrust belt in southwestern Labrador : mid-crustal structural and metamorphic configuration of a Proterozoic Orogenic thrust wedge /

Van Gool, Jeroen Antonius Maria, January 1992 (has links)
Thesis (Ph.D.)--Memorial University of Newfoundland, 1993. / Bibliography: leaves 288-303. Also available online.
38

Three investigations of accretionary wedge deformation

Breen, Nancy Ann. January 1987 (has links)
Thesis (Ph. D.)--University of California, Santa Cruz, 1987. / Typescript. "These papers describe faulting and folding observed on the seafloor using SeaMARC II side-scan sonar, seismic reflection, and 3.5 kHz data"--P. 1. Includes bibliographical references.
39

Numerical modeling of fracturing in non-cylindrical folds case studies in fracture prediction using structural restoration /

Shackleton, John Ryan, January 2009 (has links)
Thesis (Ph. D.)--University of Massachusetts Amherst, 2009. / Open access. Includes bibliographical references (p. 137-144). Print copy also available.
40

The effects of fault-induced stress anisotropy on fracturing, folding and sill emplacement : insights from the Bowie coal mines, southern Piceance basin, western Colorado /

Robeck, Eric Dean, January 2005 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Geology, 2005. / Includes bibliographical references (p. 92-97).

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