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The satellite system of Saturn has been the subject of much research in celestial mechanics since the foundation of this branch of astronomy in its classical form by Laplace in the late 18th century. It has been described as a "solar system in miniature" by virtue of the range of types of behaviour which characterise the satellite orbits. Within a single system we have A very dominant satellite (Titan) which is unaffected by periodic perturbations of a planetary type by its neighbours, and whose motion features only secular perturbations and small periodic solar perturbations. Two pairs of satellites (Mimas - Tethys and Enceladus - Dione) whose mean motions are very nearly in the ratio 2:1, causing (among other things) significant librations in the mean longitude of the satellites concerned. A satellite of rather low mass (Hyperion) whose motion is entirely characterised by a close 3:4 resonance with the dominant satellite in the system. The theory of the motion of Hyperion is a problem of such great complexity that Newcomb placed it second only to the lunar theory. A satellite (Iapetus) whose theory is dominated by large periodic solar perturbations due to the great distance at which it orbits Saturn. Moreover, the position of the orbit plane of this satellite is governed by long-period perturbations of roughly equal size acting in two widely-separated planes. This means that the secular theory of the node and inclination of Iapetus is of particular interest. This diversity of behaviour might at first appear daunting, but each satellite (even Titan) only affects its closest neighbours. Most of the satellites are very small and their perturbing effect is only noticeable when it is amplified by a near-resonance. Thus Tethys perturbs Mimas but not Enceladus or Dione, despite the fact that the latter two are its closest neighbours. We may treat the inner satellites (Mimas, Enceladus, Tethys and Dione) as a self-contained system, and likewise the outer satellites, Rhea, Titan, Hyperion and Iapetus. It is the outer satellite system, and in particular the subset consisting of Titan, Hyperion and Iapetus, that is the subject of this thesis. We choose not to include Rhea as an object for direct study, though we shall always be mindful of its perturbations upon the other three satellites. We begin in chapter 2 with a revision of Sinclair's (1974) theory of the motion of Iapetus in the light of later critical work by Rapaport (1978) and Sinclair and Taylor (1985). Both papers note that Sinclair's theory requires improvement and Rapaport investigates a near-resonance with Titan which affects the mean longitude of Iapetus. During the course of our revision, we find that the principal omissions from Sinclair's theory arise from solar perturbations in the node and inclination. These perturbations have periods of up to 29 years and affect the observed position of the satellite as seen from Earth by as much as 0.14 arc-seconds. We also find that Rapaport overestimates the significance of the Titan quasi-resonance perturbations by a factor of 3, and we present an improved theory of the motion of Iapetus which includes the additional solar and Titan perturbations. The theory is compared with Sinclair and Taylor's (1985) integration of the motion of the outer satellites to obtain a quantitative estimate of the precision of the theory. Chapter 3 contains a study of the secular motion of the orbit plane of a satellite acted upon by several perturbing forces in different fixed planes. We find that the concept of a Laplacian plane may easily be extended to any number of perturbing forces up to fourth order in the inclinations. We use auxiliary parameters p = sin i sin Ω and q = sin i cos Ω to represent the position of the orbit plane of the perturbed satellite in an arbitrary fixed reference frame and we show that the pole of the orbit describes an ellipse about a point which is the pole of the Laplacian plane of the orbit. This method is applied to the particular case of Iapetus, which is subject to significant perturbations by Titan and the Sun, and smaller perturbations due to the oblateness of Saturn. The orbit of Iapetus is shown to maintain an almost constant inclination of 7° to its Laplacian plane, upon which it precesses with a period of 3000 years. We fit this model to observed values of the node and inclination of the orbit of Iapetus and we determine the mass of Titan as a result of the fitting process. Chapters 4 and 5 are concerned with the problem of modelling the motion of Titan, Hyperion and Iapetus by numerical integration. This approach has been used by Sinclair and Taylor with some success. They fitted an integration to photographic (astrometric) observations over the period 1967 to 1982 and determined values for the initial position and velocity components of each of the satellites plus the J2 form-factor and the mass of Saturn and the mass of Titan. In this thesis we attempt to fit a similar integration to visual (micrometric) observations made during the period 1874 to 1947. Chapter 4 gives an account of the preparation of the raw data for comparison with any dynamical model. This preparation includes the reduction of the various timescales to Universal Time and Ephemeris Time, the calculation of the topocentric position vector of Saturn at the instant of each observation, and an analysis of the effects of stellar aberration and atmospheric refraction upon position angle and separation measures. In addition, we develop the partial derivatives of position angle and separation observations with respect to the Saturnicentric rectangular coordinates of the satellite(s) involved. Chapter 5 contains a description of the numerical integration method and the procedure employed in fitting the integration to the observations. It also contains an account of the results of a number of trial iterations in which we attempt to determine the parameters of the satellite system. In particular, values are obtained for the J2 form-factor of Saturn and the mass of Titan.

Platelets of divers undergo changes following exposure to high pressures and decompression. Since the latter is associated with formation of intravascular bubbles, platelet-rich plasma (PRP) was treated to reproducible doses of bubbles of air, with and without enrichment by 5% Co2 (to maintain physiological pH). PRP was also subjected to stirring and a 'rocking' procedure. Bubbles caused significant aggregation, measured turbidimetrically, of human (but not bovine) platelets, particularly without pH control, whereas little occurred with stirring and rocking. Bubbling inhibited subsequent ADP-induced aggregation of human platelets, more markedly without pH control. Bovine cells were unaffected, thus apparently less sensitive to bubbles. Since rocking was shown to be equiconvective to bubbling, aggregation associated with bubbling is not due simply to exposure of the gas/liquid interface, shear stress exerted by bubbles possibly being culpable. The importance of pH control in in vitro work was also demonstrated. PRP was next separately equilibrated (by rocking) with 5 atmospheres absolute (ata) pN2O, with 101 ata pN2 (these being approximately narcotically equipotent) and with 100 ata pHe (extremely weakly narcotic). 5 ata pN2O caused least inhibition of ADP-induced aggregation, and hydrostatic pressure (applied independently, using He and a floating plastic barrier which reduced dissolving of gas) was shown to swamp narcotic effects. It was suggested that inhibition by high pressure was due to blocking of prostaglandin synthesis. Finally, the effect of hydrostatic pressures of up to 51 ata on platelet ATP release was examined using a luciferin-luciferase assay. ADP-induced secretion was either completely blocked or partially reduced by high pressure. These effects could be important to divers suffering haemorrhages at great depths. Furthermore, in vitro hyperbaric studies are of potential value in elucidating activation pathways in platelets and other excitatory cells.

This project was desgined to ascertain the origin of debris-bearing basal ice exposed in thick sequences at the margin of the Greenland ice sheet; an understanding of basal processes is fundamental to realistic modelling both of ice sheet behaviour and of the development of glaciated landscapes. Stratigraphic, isotopic (delta18O, deltaD), structural, dynamic and sedimentological analyses of ice and debris from the ice sheet margin indicate two zones of basal ice formation and debris entrainment beneath the ice. At some point in the interior, water freezes to the bed in small increments across a transition zone between warm and cold based areas. This interior derived basal ice re-crystalises during flow, may undergo pressure melting and regelation, and appears at the ice sheet margin as an isotopically distinctive ice facies with large clear crystals and with gas and debris pockets at crystal boundaries. Close to the margin, particularly in zones of faster flowing ice, some of this basal ice melts from the bed. Water derived from this melting, and from penetration of surface meltwater, re-freezes at the bed in a narrow freezing zone at the very edge of the ice sheet, forming a sequence several metres thick of ice and debris laminae. Compressive flow at the margin, related to seasonal freezing as well as to marginal thinning of the ice, causes folding and thrust-faulting within the glacier. This thickens the basal sequence, and raises material from the basal layers and from the basal transport zone into the body of the glacier to form debris bands. At the very margin, accumulations of snow, superimposed ice, and debris are overriden and incorporated into the lowest part of the basal sequence. These findings have implications for basal thermal conditions, ice rheology, the distribution of zones of sub-glacial geomorphic activity, and the structure of ice sheet sediments.

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Lingonberries (Vaccinium vitis-idaea) are edible fruit that belong to the Ericaceae plant family. A growing body of evidence suggests that consumption of berries provide considerable health benefits due to their high polyphenols, antioxidants, vitamins and mineral content. Therefore, it is beneficial to evaluate the antioxidant capacity of berries in order to select lines with higher antioxidant capacity. The aim of this study was to determine the antioxidant capacity, total phenolics, total anthocyanins, anti-apoptotic effect and the metabolomic profile of lingonberries from Northern Manitoba (wild) and Newfoundland (greenhouse-grown). A total of 159 lingonberry samples were collected from Northern Manitoba (Lynn Lake and Flin Flon) and Newfoundland. Samples were freeze dried, lyophilized, ground into powder and extracted with solvent methanol. Total anthocyanins were determined by the pH differential method. Total phenolics were evaluated by the Folin-Ciocalteau’s assay, the anti-apoptotic effect was measured fluorescently and the oxygen radical absorbance capacity (ORAC) assay was utilized to evaluate the antioxidant capacity. Our study showed that Northern Manitoba-grown lingonberries contain a higher level of anthocyanins and phenolics compared to Newfoundland greenhouse-grown lingonberries. Results show that Northern Manitoba- grown lingonberries have higher antioxidant capacity compared to ones grown in Newfoundland. Findings from the study suggest that berries grown in green house conditions and extreme climatic conditions have different antioxidant capacity, anti-apoptotic effects, total phenolics and total anthocyanins; that is, more extreme climates may result in berries with higher antioxidant capacity, total phenolics and anthocyanins. / May 2016

Ph.D. (African Languages) / The main concern of this study has to do with the investigation of linguistic variation and standardization in Setswana. We are of the idea that linguistic variation and standardization occur as a result of both internal and external factors. Focus of this study was both on some of those areas inhabited by Batswana both in Botswana and South Africa. An investigation has been made on the different orthographies used in these countries. Although their orthographies presently differ, they were initially the same. They separated after the revision of the 1937 orthography version by the then Tswana Language Committee in South Africa. But, however, Setswana Standard Orthography 1981 (1981) in Botswana, is the same as Tswana Terminology and Orthography No.3 (1972) in South Africa. This similarity was caused by the great influence and presence of Professor E.S. Moloto. Botswana dependency on South Africa during that time, on language planning may have been because 'South Africa has more speakers of Setswana, has had larger total resources in money and manpower, and thus rather naturally took the lead and Botswana ended following suit' (Janson and Tsonope, 1991:78). During that time, South African policies were directed by the ideology of the apartheid system. So, 'to ignore linguistic developments in South Africa was impossible, but to accept them has often been unpalatable and maybe important' (Janson and Tsonope, 1991:78). Data collected bear testimony that standard language is what Botswana people really want to be taught at schools and tertiary institutions. Most of them do not really understand why their children are expected to use standardized language as formal style. The reason behind all these is that they were never involved in language planning. Therefore, there is great need to involve people from different sectors where Setswana is involved. The language policy for the new South Africa in the future should be written in all official languages not just in English and Afrikaans only (refer to Government Gazette, 9 May 1997).