Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains ix, 125 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 98-125).

Thesis (M.S.)--West Virginia University, 2010. / Title from document title page. Document formatted into pages; contains vii, 83 p. : ill. Includes abstract. Includes bibliographical references (p. 59-74).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 79-88).

This thesis is divided into two parts; Part I consisting of the theory and Part II the experimental work. Part I is divided into three sections; in Section 1 a summary is given of collision processes and how they have been used to explain various experimental results; this is followed in Section 2 by the author's interpretation of some previous experimental observations; a summary of the wave mechanical theory of collisions is given in Section 3. Part II consists of four sections; In Section 1an outline is given of the various ways of exciting spectra and this is followed by a description of the apparatus used by the author in Section 2; the results of the experiments with hydrogen and oxygen are given in Section 3, and the theoretical interpretation of these; the last Section deals with the experiments carried out with hydrogen and helium, and the facts which may be inferred from these experimental results.

M.Sc. (Botany) / The purpose of this investigation was to determine the effects of various physical treatments (limitation of transpiring surface, removal of stem base and changing of vase water and different numbers of inflorescence per constant volume of vase water) on the browning of foliage and the rate of water absorption by Protea neriifolia in florescences. The binding capacity of lead acetate with flavonoids in vase media was also determined. The limitation of the number of leaves (transpiring surface) per peduncle resulted in less absorption of leached browning and stem plugging components. Regular removal of the stem base and changing of vase water inhibit stern blockage and accumulation of leached products in the vase medium. A large number of inflorescences in a limited volume of vase medium resulted in higher concentrations of leached flavonoids and other browning components. A reduced number of leaves per peduncle, regular removal of stern base and changing of vase water, as well as a limited number of inflorescences per constant volume of vase medium, ensured adequate continuous water uptake, which is essential to limit browning.

Permeability changes in membranes of Protea neriifloia leaves during senescence were investigated. A complete preservative consisting of a-hydroxyquinoline sulphate (8-HQS), silver nitrate (AgN03), citric acid and sucrose was formulated by using different concentrations of the components. The % browning of the leaves, change in mass of the inflorescence and their water uptake over a period of 20 days was used as a measurement to determine the most effective concentrations. The results lead to the formulating of an effective preservative which can be used commercially. The preservative consists of 100 mg 8-HQS, 5 mg AgNo3, 100 mg citric acid. and 10 g sucrose, made up to 1 litre with distilled water. Scanning electron microscopy was used to investigate the effects of a complete preservative on protea leaves. The respiratory rate and water content of leaves from inflorescence in preservative and distilled water was determined and compared. The respiratory rate of leaves of inflorescence in preservative was considerably higher than that of the control. The preservative also resulted in the leaves having a better retention of their water...

No abstract available / Dissertation (MSc (Mathematics))--University of Pretoria, 2008. / Mathematics and Applied Mathematics / unrestricted

Variability in the relationship between tree leaf area (TLA) and selected stem measurements was examined in three Douglas-fir stands (Pseudotsuga menziesii (Mirb.) Franco, var. menziesii) that were less than 50 years-old, spaced to approximately 550 to 650 stems/ha, and differed in soil moisture and nutrients. Attention was given to the effect of mean annual ring width (MARW), cross-sectional area of the live bark (ALB - a surrogate measure of relative nutrient storage in the stem), and cross-sectional area of the most recent annual rings equal in number to the number of whorls in the live crown (ALC), on variability in the relationship between TLA and cross-sectional area of sapwood (ASW). At breast height, basal area, ASW, and cross-sectional area of sapwood plus live bark (ASWLB) were not linearly related to TLA, and linear regression equations using log transformed variables varied significantly between sites. Nonlinear regression equation for ASW at breast height was: TLA = 0.064ASẆ¹•³³ (I² = 0.856). Including D (the distance between breast height and the center of the live crown) in the nonlinear equation, did not significantly improve the regression. Tree leaf area prediction models using stem measures from the base of live crown (blc) had higher adjusted R² values than models using stem measures from breast height. At the blc, basal area, ASW, and ASWLB were linearly related to TLA (adjusted R² = 0.926, 0.908, and 0.934, respectively). Multiplying ASW by MARW did not improve the fit of the regression models. Multiplying ASW by ALB improved the linearity of the relationship of ASW at breast height to TLA. The best fitting TLA model overall used the product of ASW at blc and ALB at blc as the independent variable (adjusted R² = 0.967). The results indicate that research into the allometric relationship of TLA to stem measures should give consideration to more than hydraulic measures and include measures of bark function. At breast height and the blc, the independent variable ALC was linearly related to tree leaf area and had higher adjusted R² values than did ASW. In most trees the ALC stem measure was found to include a portion of heartwood area. The strong relationship between TLA and ALC suggests that a given transpiring leaf mass or area is related to a proportional amount of conducting stemwood and physical support stemwood. A quick alternative approach for estimating individual tree leaf area using photographs taken at fixed distance and angle from the target tree did not result in a reliable tree leaf area prediction technique. The difficulty of obtaining views of the tree crown which were not obstructed by adjacent tree crowns was the major obstacle. Using a fixed distance and camera angle was a problem because of variable tree heights. However, altering these fixed positions introduced additional variation into the tree leaf area estimation. Mean specific leaf area (SLA) varied significantly by site, needle age class, and crown position. Mean SLA per needle age class per branch can be predicted with 95% confidence and a 10% allowable error using six 10-needle samples. / Forestry, Faculty of / Graduate

M.Sc. / Pteronia L. is a genus of 70 species of woody shrublets occurring mainly in southern Africa (Leistner, 2000). Published and unpublished ethnobotanical information exists for nine of the species. The uses of these species in traditional medicine are poorly recorded or have remained scientifically unknown. In addition, some unpublished vernacular names have been recorded during this study. Hutchinson and Phillips revised the genus Pteronia in 1917 and grouped the species into four sections. The nine ethnobotanically important species were placed in four sections: Incanae (P. incana and P. cinerea), Papillatae (P. lucilliodes and P. divaricata), Ciliatae (P. camphorata, P. stricta, P. onobromoides and P. adenocarpa) and Glabratae (P. succulenta). Pteronia onobromoides is the original source of Nama buchu that was first recorded by Van der Stel in 1685 (De Wet & Pheiffer, 1979), but which has remained poorly known. Surprisingly, this study has revealed the existence of an important Cape herbal medicine (P. divaricata) for which no record could be found in the scientific literature. Pteronia incana is not widely known for its traditional medicinal uses (although a few have indeed been recorded) but rather as a source of valuable essential oil that has been commercially exploited to some extent. Other species with at least one published anecdote of traditional use include P. adenocarpa, P. camphorata, P cinerea, P. lucilioides, P. stricta and P. succulenta. This means that a total of nine species are now known to have traditional medicinal and/or cosmetic uses. Most of the species are used for intestinal disorders (including stomach pain) and respiratory ailments (coughs, colds and influenza). The topical application of P. onobromoides and P. adenocarpa is clearly aimed at more than just a cosmetic effect and includes the alleviation of pain and the treatment of wounds and skin ailments. These uses all suggest that Pteronia species may have antimicrobial activity and also possible anti-inflammatory and analgesic properties. Pteronia adenocarpa is only known from a single literature record.

Ph.D. (Botany) / Please refer to full text to view abstract