No description available.

No description available.

No description available.

No description available.

The pollinator spectrum, diversity of flower colour, natural pollination and fruit set levels were examined in Scottish <i>L. borealis </i>patches.  Flowers were visited by a diverse spectrum of insect pollinators but, despite high natural pollination levels, fruit set was very low in the majority of patches examined.  The breeding system of <i>L. borealis </i>was confirmed as highly self-incompatible and limited compatible mate availability was identified as the cause of reproductive failure.  Due to the limited pollen dispersal capabilities of flies which dominate the pollinator spectrum, isolation from pollen exchange between compatible mates began at very short distances.  A diversity of compatible mates situated within close proximity (&lt;6 m) was shown to be the key requirement for high natural fruiting success in <i>L. borealis.  </i>Cross-pollination between neighbouring <i>L. borealis </i>patches resulted in high fruiting success suggesting that transplantation of compatible mates into isolated patches could restore their reproductive success. Natural pollination levels were generally high on Colonsay and a very low, but consistent, level of capsule and seed set was recorded in most years.  Capsules produced by Colonsay plants contained very low quantities of seed (&lt;100/capsule) and high numbers of empty testa, and seed set was extremely low (&lt;1%).  Severe reproductive failure was evident and the cause was attributed to self-incompatibility and/or inbreeding depression.  Seed set was also very low for all of the crosses made within Scotland, even between the two distinct genetic groups.  The high levels of seed set achieved following crossing of Scottish and North American plants suggest that restoration of reproductive success in Scotland may require the introduction of some North American genes.

The thesis is concerned with the derivation of anisotropic intermolecular potentials from experimental data. For the rare gas - hydrogen halide systems the most useful experimental results are those from molecular beam rotational spectra of van der Waals complexes and from pressure broadening of hydrogen halide rotational spectra by rare gases. Intermolecular potentials for the Ar.HCl system had previously been obtained from each of these experiments separately, but none of the potentials proposed succeeded in reproducing all the available data. In the present work, improved theoretical methods are developed for the calculation of molecular beam spectra and line broadening cross sections from a proposed intermolecular potential. The methods developed are substantially faster than those previously available, allowing their use in a least squares procedure to determine potential parameters. Several possible parameterisations of the intermolecular potential are then considered for Ar.HCl, and least squares fits of potential parameters to experimental results are performed for this system. Measurements of total differential cross sections and second virial coefficients are included in the least squares fits, in addition to the experiments mentioned above. The experimental data demonstrate conclusively that the equilibrium geometry of Ar.HCl is linear, with the atomic arrangement as written. The equilibrium intermolecular distance is 400±3 pm, with an absolute well depth of 18andpm;10 cm^-1 . The only feature of the potential which is not well determined by the experimental results is the behaviour around the linear Ar.Cl-H geometry. The results for Ar.HCl are then extended to the systems Ne.HCl, Kr.HCl and Xe.HCl, allowing the dependence of the intermolecular potential on the rare gas to be considered. The molecular beam spectra for Ne.HCl can be fitted only by a potential with a secondary minimum at the linear Ne.Cl-H geometry, in addition to the primary minimum at the linear Ne.H-Cl geometry. The experimental results for the other rare gas - HC1 systems are not very sensitive to this feature of the potential, and the potentials for these are constrained to be similar to that for Ne.HCl in this region. The potential surfaces for all the rare gas - HC1 systems have similar shapes, and appear to be nearly conformal. Finally, intermolecular potentials are obtained for the systems Ar.HF, Kr.HF and Xe.HF from molecular beam spectra. The experimental data for these systems are less extensive than for the HC1 systems, and the potentials obtained are reliable only in the region of the absolute minimum. The HF systems are considerably more anisotropic than the HC1 systems, and it is suggested that this is principally due to greater induction forces in the HF systems. Experiments are suggested which would provide further information on the intermolecular potentials for both HF and HC1 systems, and predictions of the results are made using the current best fit potentials.

Typescript (photocopy) / 167 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.) Dept. of Physics, University of Adelaide, 1978

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

The Hoidas Lake Rare Earth Element (REE) Deposit is one of several REE showings which are spatially associated with a regional-scale fault system that cuts through the Rae Province in northern Saskatchewan. The showings occur along the Hoidas-Nisikkatch fault, believed to be a subsidiary of the Black Bay Fault, and consist of multiple REE-enriched veins. Surface outcrops and drilling have delineated a vein system, called the JAK zone, which extends for over 1 km along strike, with the system remaining open both along strike and down dip. The majority of the REE are hosted by fluorapatite and allanite-(Ce), although there are also minor amounts of monazite, bastnaesite and chevkinite which can contain significant concentrations of REE. The veins are dominantly LREE-enriched, specifically La, Ce, and Nd.<p> The mineralization at Hoidas Lake is complex, with the chemical and mineralogical compositions changing with each vein generation. The earliest veins consist of REE-bearing allanite and chevkinite which occur in association with clinopyroxene, titanite, and hyalophane. The allanite-rich veins are followed by veins dominated by red or green apatite, both of which are typically brecciated. Finally, there is a late apatite which crosscuts all previous vein generations. Each of the distinct apatite generations shows discrete chemical variations, particularly in their light rare earth element content, with the total rare earth oxide content ranging from approximately 1.5% in the oldest apatite to as much as 5% in the green apatite.<p> The majority of the apatite and allanite crystals are strongly zoned, reflecting the chemical changes in the mineralizing system through time and, particularly in the earliest vein generations, there are signs of hydrothermal alteration. The early apatite generations typically show the development of monazite inclusions which suggests interaction with hydrothermal fluids, as do the REE-poor rims and bastnaesite alteration observed in the majority of the allanites.<p> The veins are fault controlled and are interpreted to be late magmatic- hydrothermal in origin, with the fluid derived from a magmatic source at depth. Although the exact source of the fluids remains uncertain, the high concentration of REE, as well as Sr and Ba, and a relative depletion in high field strength elements suggests that the mineralization may be related to either an alkali or carbonatitic source.

The Hoidas Lake Rare Earth Element (REE) Deposit is one of several REE showings which are spatially associated with a regional-scale fault system that cuts through the Rae Province in northern Saskatchewan. The showings occur along the Hoidas-Nisikkatch fault, believed to be a subsidiary of the Black Bay Fault, and consist of multiple REE-enriched veins. Surface outcrops and drilling have delineated a vein system, called the JAK zone, which extends for over 1 km along strike, with the system remaining open both along strike and down dip. The majority of the REE are hosted by fluorapatite and allanite-(Ce), although there are also minor amounts of monazite, bastnaesite and chevkinite which can contain significant concentrations of REE. The veins are dominantly LREE-enriched, specifically La, Ce, and Nd.<p> The mineralization at Hoidas Lake is complex, with the chemical and mineralogical compositions changing with each vein generation. The earliest veins consist of REE-bearing allanite and chevkinite which occur in association with clinopyroxene, titanite, and hyalophane. The allanite-rich veins are followed by veins dominated by red or green apatite, both of which are typically brecciated. Finally, there is a late apatite which crosscuts all previous vein generations. Each of the distinct apatite generations shows discrete chemical variations, particularly in their light rare earth element content, with the total rare earth oxide content ranging from approximately 1.5% in the oldest apatite to as much as 5% in the green apatite.<p> The majority of the apatite and allanite crystals are strongly zoned, reflecting the chemical changes in the mineralizing system through time and, particularly in the earliest vein generations, there are signs of hydrothermal alteration. The early apatite generations typically show the development of monazite inclusions which suggests interaction with hydrothermal fluids, as do the REE-poor rims and bastnaesite alteration observed in the majority of the allanites.<p> The veins are fault controlled and are interpreted to be late magmatic- hydrothermal in origin, with the fluid derived from a magmatic source at depth. Although the exact source of the fluids remains uncertain, the high concentration of REE, as well as Sr and Ba, and a relative depletion in high field strength elements suggests that the mineralization may be related to either an alkali or carbonatitic source.