1,408 results for University of Canterbury Library, 1990

  • The failure of corporate failure models to classify and predict : aspects and refinements

    Alexander, P. B. (1991)

    Masters thesis
    University of Canterbury Library

    Much has been written about the use of multiple discriminant analysis in corporate distress classification and forecasting. Classification and prediction models are notoriously difficult to establish in such a way that they will stand the ultimate test of time. Many articles severely criticise the use of the technique yet there are aspects which may improve our ability to develop satisfactory models. We are probably yet a long way off from being able to do so with any great degree of satisfaction, yet it behoves us to try to develop models that do justice to the assumptions and the theory. This thesis explores several important aspects of the model-building process and concludes that some of the more conventional criticisms of the models developed so far are less important than claimed. It suggests that more critical than the failure to meet the conditions of multivariate normality, the equality of the variance-covariance matrices, and the use of a priori probabilities are the need for: a satisfactory model specification that can be theoretically justified, the strict use of random sampling, the efficient use of sample data, the search for stable mean vectors which are significantly different from each other, and ex ante validation. If these requirements are met then the MDA technique is robust enough to cope with breaches of the assumptions.

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  • The state and income redistribution: a study of the social wage and taxation in New Zealand 1949-1975

    Reveley, J. W. C. (1990)

    Masters thesis
    University of Canterbury Library

    This thesis examines the role of the state in redistributing income between social classes in New Zealand during the years 1949-1975. It applies an innovative methodology, developed by E. Ahmet Tonak, to a set of data drawn from New Zealand's national accounts and estimates a quantity labelled 'net-tax', defined as the taxes that the working class cede to the state less the expenditure that the working class receives from the state in the form of a social wage. A detailed theoretical discussion precedes the empirical analysis. Insofar as Tonak's method requires that the social wage (the portion of state expenditure consumed by the working class) be identified as an empirical quantity, the argument that all taxes, and hence all state expenditures, originate from surplus value is confronted. The views of the main representatives of this contemporary school of thought are subjected to detailed scrutiny. They are rejected in favour of the views of a school which considers the portion of taxes funding the state expenditure that constitutes the social wage to originate in 'wages'. A model which theoretically 'grounds' the comparison of taxes paid to state expenditure received, effected in the remaining chapters of this study, is then formulated. In the empirical analysis, the empirical referent of the 'net-tax' concept is calculated for the years 1949-1975. The net-tax data set is then used to construct a transference ratio, which indicates the degree and direction of income redistribution effected by the state. The main finding to emerge is that, in all but one of the twenty-seven years surveyed in this study, the working class has surrendered more wealth in taxes to the state than it has received back from the state as a social wage. In light of these results, it can be concluded that the welfare state has not materially benefitted the working class in New Zealand. Moreover, insofar as income has consistently been redistributed from the working class to 'non-labour' (the capitalist class and the state itself), the state can be considered to owe the working class a debt in the amount of 3671.26 million (constant 1975) dollars.

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  • The impact of the Internet on small firms

    Martin, Ross A. (1998)

    Masters thesis
    University of Canterbury Library

    Several researchers have designed frameworks to model and analyse impacts of the Internet on firms. This research takes one such framework aimed at small firms (Lymer et al., 1997b) and attempts to validate its usefulness by comparing it to similar and conflicting models, and by applying it to impacts collected from both the literature and from four case studies of small firms. The findings suggest that several changes to Lymer et al.'s (1997b) framework are necessary to make the model more effective and more practical for researchers and practitioners. A revised Internet impacts model is proposed that incorporates these changes. Preliminary evaluation has been performed on the revised model, resulting in the conclusion that the study makes a valuable contribution to the area of Internet research by significantly enhancing the usability and analytical usefulness of Lymer et al.'s (1997b) Internet impacts model.

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  • Promoting sustainable management in local resource management issues

    Weastell, Lynda (1994)

    Masters thesis
    University of Canterbury Library

    The Resource Management Act (RMA) 1991 is a much discussed and frequently criticised piece of legislation in New Zealand. The RMA 1991 is much discussed because it is part of a substantial reform of New Zealand's resource management law. It is much criticised because the overall purpose of the RMA 1991 is to promote the sustainable management of natural and physical resources (S.5(1)) but the meaning given to sustainable management in the RMA 1991 (S.5(2)) is ambiguous. These discussions and criticisms focus on the legislation. Little research on promoting sustainable management in the context of resource management practice has been undertaken so far. This research needs to be done because the context of resource management issues and the public planning process will influence how sustainable management is interpreted and applied in resource management practice. This thesis is a comparative analysis of promoting sustainable management in four local government resource management issues: the northern access road issue, Christchurch; underground coal mining at Mount Davy, Rewanui; subdivision of Travis Swamp and Kennedy's Bush Spur, Christchurch; and air access into Westland National Park. The aims of the research are to establish: how sustainable management is being promoted in resource management practice; how important the RMA 1991 and promoting sustainable management is in determining resource management outcomes in the public planning process; and whether promoting sustainable management is resulting in a radical change in resource management practice. The thesis makes three conclusions. Firstly, that while sustainable management is an ambiguous concept a 'working' interpretation is emerging in resource management practice based on managing adverse environmental effects. Secondly, that the RMA 1991 and promoting sustainable management is important to legitimise resource management proposals in terms of the law, but it is not the raison d'etre for these proposals. Thirdly, that promoting sustainable management has resulted in changes in the way in which resource management proposals are assessed, but there are a lot of conitunities in resource management practice despite resource management law reform.

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  • The environmental concern of commerce students -a survey

    Saunders, Louise M. (1996)

    Masters thesis
    University of Canterbury Library

    The evolution of attitudes towards the environment has culminated in the entrenchment of environmental concern as a characteristic of Western society. Overseas research has found young, well educated, urban individuals are most likely to express concern for the environment. However, the features of environmentally concerned New Zealanders have largely failed to attract the attention of researchers. In a sample of University of Canterbury Commerce students, aspects of environmental concern, and salient issues, were identified. As expected, individuals raised in urban centres were more likely to express environmental concern, although the expected influence of age and education were not observed. Women were more concerned about the environment, as were New Zealand-raised and New Zealand-ethnic respondents. It was concluded that the environmental concern of this population has many similarities to populations in other Western nations in the salience of issues, the issues of concern, and the levels of concern shown. As the respondents in this study were not representative of the New Zealand public, the suggestions for further research focus on the need to investigate environmental concern in a representative sample. A need was also suggested for research into areas of specific concerns, actual behaviour, commitment, and knowledge in the New Zealand population.

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  • An examination of employees' observations and informal information in a distressed organisation : the case of Fortex Group Limited

    Tobin, Scott Mylrea (1995)

    Masters thesis
    University of Canterbury Library

    A review of previous qualitative corporate distress research reveals that non-managerial employees appear to have been overlooked as a potential source of information on a failed company. Yet assertions by Argenti (1976a) and an analysis of Altman's (1983) and McBarnet, Weston and Whelan's (1993) research indicates that employees can potentially observe the symptoms of distress. However, Argenti (1976a) reported that employees could only observe the non-financial systems of distress, and that they could not determine that an organisation was distressed. McBarnet et al's (1993) research and a pilot case study indicated otherwise. The pilot study also found that employees had access to the informal communication network, or grapevine, and an informal accounting information system (IAIS). McBarnet et al (1993) report that informal information may assist employees to detect problems or unusual events within a company. Consequently, this research sought to clarify the anomaly between Argenti's assertions and McBarnet et al's (1993) and the pilot study's findings, determining the problems or concerns that employees observed in a company before. it collapsed, and whether these observations could cause employees to believe that a company was distressed before it failed. The research also examined whether information from an IAIS and/or the grapevine contributes to employees' observations and opinions in a distressed company. A single case study of a failed organisation was conducted. The subject was Fortex Group Limited, a South Island meat-processing company. The findings challenged and extended previous beliefs regarding employees' observations in a distressed company, indicating that they may not only observe the symptoms of distress, but also observe the defects and mistakes which cause, and contribute to, failure. Moreover, from the symptoms observed, the employees recognised that the company was distressed. The research also established preliminary links between the grapevine, IAISs, employees' observations and corporate distress. Each area was identified as an alternative source of information which could potentially assist the early detection of corporate distress. Despite limitations, this research increases the body of knowledge in these areas, and recommends directions for future research.

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  • Wavefront estimation in astronomical imaging.

    Irwan, Roy (1999)

    Doctoral thesis
    University of Canterbury Library

    The challenge in building astronomical telescopes is to obtain the clearest possible image of a distant star, which should appear as a single point. Extended objects, such as galaxies and planets can be regarded as collections of points. However, turbulence in the atmosphere degrades any optical signal that passes through it. The optical effects of the atmospheric turbulence arise from random inhomogeneities in the temperature distribution of the atmosphere. As a consequence of these temperature inhomogeneities, the index of refraction distribution of the atmosphere is random. Plane waves striking the atmosphere from space objects acquire an aberration as they propagate through the atmosphere. The plane wave's surface of constant phase is no longer planar when intercepted by a,n a.stronornica.l telescope. The prnctica.l consequence of a.tmospheric turbulence is that resolution is generally limited by turbulence rather than by optical design and quality of a telescope. There are a number of approaches to solving this problem, ranging from an orbiting telescope (the Hubble Space Telescope), adaptive optics, and post detection processing. The latter approaches have applications to less expensive ground based telescopes and have been the subject of many years of research. Adaptive optics is a general term for optical components whose characteristics can be modified in real time so as to alter the phase of an incident optical wavefront. An adaptive optics system can be used to correct for atmospheric induced distortions. Before any corrections can be applied, however, some measurement must be made of the phase distortions. It is the aim of this study to estimate the degradation of the wavefronts phase. Two approaches to do so are presented. Firstly, through wavefront sensors, which many adaptive optics systems have been devised from. Among them the Shack-Hartmann sensor is the most commonly used. The sensor requires a subdivision of the receiving pupil by means of sub-apertures, wherein the lowestorder deformation of the wavefront phase is estimated. This linearizes the problem of phase retrieval to solving a linear system of equations. A new analysis is presented which differs from previously published work in the estimation of the noise inherent in the centroid calculation used in this sensor. This analysis is supported by computer simulations. Secondly, the nonlinear approach of phase retrieval is discussed. The problem becomes how to relate the phase and magnitude of the Fourier transform. It is thus necessary to estimate the phase distortion in the instrument solely from measurements made at the image plane of the telescope. The process of phase retrieval is then divided into two distinct steps. The expression for the covariance of the phase distortion using a Kolmogorov model for the turbulence is derived first. This covariance is then employed as part of a formal Bayesian estimate of the phase distortion. It is also shown that phase retrieval can be employed as a robust technique for estimating the wavefront distortion using a lenslet array. The results obtained compare favorably with the alternative approach of phase diversity. Furthermore, the introduction of prior information, in the form of statistical information of the distortion, is shown to considerably enhance the success of the phase retrieval especially for very low light levels. A comparative evaluation shows the superiority of phase retrieval to Shack-Hartmann sensing, only if the local maxima are overcome. The principal drawback of phase retrieval is the relatively long computing time required to find the solution when general-purposed computer is used.

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  • Infinite antichains of matroids with characteristic set {p}

    Oxley, J.; Semple, Charles; Vertigan, D.; Whittle, G. (1999)

    Reports
    University of Canterbury Library

    For each prime p, we construct an infinite antichain of matroids in which each matroid has characteristic set {p}. For p=2, each of the matroids in our antichain is an excluded minor for the class of matroids representable over the rationals.

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  • Interpretation of some Paleocene fluvial sediments from the Upper Pakawau and Kapuni groups, Pakawau Sub-basin, North-West Nelson

    Stark, C.J. (1996)

    Masters thesis
    University of Canterbury Library

    Fifteen key measured sections form the basis for detailed facies analysis of Paleocene upper North Cape Formation (Pakawau Group) and Farewell Formation (Kapuni Group) sediments, northwest Nelson. Based on structural, textural and compositional variations, the sediments were divided into eight lithofacies associations (LAA3, LAA4, LAA5, LAA6, LAA7, LAB1, LAB2 and LAB3). Associations A3 to A7, North Cape Formation, represent a progradational sequence of floodplain (LAA3), lacustrine (LAA4), low energy meander (LAA5 and LAA6), and braided river deposits (LAA7). LAB1, LAB2 and LAB3 are interpreted as meander, gravel dominated and sand dominated braided systems. The conformable boundary between LAA3 and LAA5 on the northwestern side (Moki Point) of the Whanganui Inlet means the transition from an axial system to system flowing perpendicular to the axis of the Pakawau Sub-basin does not represent the contact between the Kapuni Group and Pakawau Group. Progradation of a fluvial system passing through the space between en echelon faults in the west would explain the paleocurrent change from parallel to perpendicular to the main axis of the Pakawau Sub-basin. A higher rate of subsidence toward the north along the Wakamarama Fault is inferred from a lateral northerly-coarsening trend between LAA6 and LAA7. Erosional contact between LAA6 and LAB2 on the northern side of the Whanganui Inlet is interpreted as the upper contact of the North Cape Formation. The absence of fluvial association LAA5-LAA7 on the southern side of the Whanganui Inlet Entrance suggests a period of uplift and subsequent erosion of prior to the deposition of associations LAB1-LAB3 deposits. The preferred explanation for the localized uplift and erosion of fluvial association A deposits is by activation of intrabasin antithetic and synthetic faults. LAB1 is inferred to represent a 'feeder' system associated with LAB2 and LAB3. The basal contact of LAB1 on the southern side of the Whanganui Inlet is thus inferred to represent the boundary between the North Cape and Farewell Formations. The downstream coarsening of LAB2 and LAB3 is best interpreted by coarse grained sediment being fed from active (penecontemporaneous) intrabasin antithetic and synthetic faults and/or the Kahurangi fault in the west. The interpretation of the Wakamarama Fault as a growth fault during the deposition of LAB1, LAB2 and LAB3 is supported by the lack of change in grain size of LAB1 up-section and the fine grained texture of LAB3 at Abel Head. The change in position of the North Cape Formation upper contact results in the recognition of a new lithostratigraphic unit, the Wharariki member, for the fluvial deposits upon LAA3. Also LAB1 is deemed sufficiently structurally, texturally and compositionally distinct to suggest it be called the Whanganui Member of the Farewell Formation. The boundary between association A and association B sediments is interpreted as a type 1 sequence stratigraphic boundary.

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  • Ring laser dynamics.

    King, Benjamin Thomas (1999)

    Doctoral thesis
    University of Canterbury Library

    The departure of the behaviour of large ring laser gyros from the ideal is examined. A detailed description of the experimental operation of large ring lasers is provided along with several new innovations in equipment layout, data collection and especially in data reduction. The limits on gyro performance due to noise are investigated. A review of literature regarding the fundamental limit placed on gyro resolution is provided. This limit is due to spontaneous emission in the gain medium of the laser and it is demonstrated that our ring lasers approach this quantum limit. Two entirely independent methods for evaluating the quantum noise induced linewidth are demonstrated to agree well. One of the methods, which uses a second order autoregressive model, is able to make accurate linewidth estimates in sub-second gate times. A complex model is proposed which accounts for specific observed light scattering phenomena within a ring laser. This model is compared with dual beam data taken from C-I and is able to describe frequency shifts and waveform distortion accurately. The model also performs favourably when describing locking profiles for low rotation rates and externally induced perimeter modulation. When locked to an external signal the ring laser is found to be an extremely sensitive low frequency vibration detector. The commissioning of a very large (14 m perimeter) prototype ring laser gyro, GO, is described along with a comparison with the smaller ( 4 m perimeter) gyros C-I and C-II. This prototype has proven to be an invaluable testing ground for designs and techniques to be used on a proposed high precision 16 m perimeter gyro named the Grossring (G).

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  • The treatment of childhood in the novels of Charlotte and Emily Brontë

    Tan, Elis Peak Neo (1990)

    Masters thesis
    University of Canterbury Library

    In this thesis I have dealt with Charlotte and Emily Bronte's representation of children in their novels, and the significance of childhood as it reflects or suggests the authors' attitudes to morality, character, and society. I have studied what Charlotte and Emily overtly or covertly say about children and the adults that they grow into, as a means of assessing the similarities and differences in the sisters' attitudes, taking into consideration as well, how these attitudes compare with contemporary images of childhood. I have chosen to examine the published novels of Charlotte and Emily, and have used for my research both critical and biographical material written on the Brontes. In chapter one, I introduce both writers vis-a-vis two major influences in Victorian literature, namely, religion and romanticism, comparing the extent to which the sisters are affected by these opposing traditions in their treatment of childhood. Chapters two and three deal separately with Charlotte and Emily and their novels. The final chapter offers a conclusion with regard to the similarities and differences between these authors, including the distinction between their narrative techniques that reflect their differing literary motives. Unlike Charlotte, Emily wrote for personal catharsis and awareness rather than for didactic reasons. While both Brontes reveal their moral attitudes on the question of childhood, Emily, unlike her sister, remains non-judgmental. Also, although both sisters accept harsh reality, Emily seems to do so reluctantly compared to Charlotte who is quite unambiguous about it.

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  • Groundwater contamination in the Heathcote/Woolston area, Christchurch, New Zealand

    Hertel, Ingrid (1998)

    Masters thesis
    University of Canterbury Library

    Christchurch City (population 360,000) depends entirely on an underlying stratified, leaky, confined, artesian aquifer system to provide untreated water for its residents and industries. Concerns have been raised by the Canterbury Regional Council about brackish water entering the aquifer system in a localised area in the south-eastern part of the City (Woolston/Heathcote). Due to the coastal, urban, and geological, setting of the area several possible groundwater contaminant sources exist and needed to be investigated. These include: seawater, urban wastes, thermal groundwater, and connate seawater. A potentiometric survey carried out in the area, combined with water quality sampling, hydrogeological information from previous studies, and previously obtained water quality data, provided the basis for a conceptual model of groundwater contamination. Downward leakage of estuarine water through the confining layer appears to be the dominant contaminant source. In the past, the potential risk of seawater intrusion has been regarded as low for the Christchurch artesian aquifer system. The freshwater/seawater interface was considered to be located 40km offshore where the uppermost confined aquifer intersects with the sea at its submarine outcrop. To enhance the understanding of freshwater and saltwater flow dynamics of the aquifer system, a steady-state crosssectional finite-difference model along the coast of Christchurch has been constructed and calibrated. The modelling indicated that the location of the freshwater/seawater interface is dominated by leakage from the sea through the confining layer and not, as presumed before, by lateral inflow of seawater through the offshore outcrop. Consequently the interface location is to be expected much closer to the shoreline at approximately 3km offshore. Groundwater contamination in a localised area in Christchurch has demonstrated that the uppermost confining layer does not act as an effective barrier towards seawater intrusion where the hydraulic gradient between the sea and the aquifer is directed downward. A groundwater level and quality monitoring network, and a groundwater model specific to the study area, have been constructed to facilitate the future management of the resource. Immediate pumping restrictions are needed on 3 major abstraction wells to increase potentiometric heads that currently sit below sea level. An upward hydraulic gradient between the uppermost aquifer, the estuary, and the confining layer, is essential to protect the aquifer from ongoing downward leakage of saline contaminant sources. Ongoing monitoring of water levels and groundwater quality is recommended. This data will allow more refined modelling of management scenarios.

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  • The conceptual distinction between liabilities and equity : a new approach required

    Crook, Kimberley (1998)

    Masters thesis
    University of Canterbury Library

    This thesis examines the conceptual distinction between liabilities and equity, in the context of business entities, by means of a literature review. It is shown that the conceptual distinction between liabilities and equity requires consideration of the underlying equity theory. Various equity theories are compared, including the entity, proprietary and residual equity theories, which each view liabilities and equity, and the distinction between the two, differently. In addition to these well-known equity theories, another equity theory is presented, that has received little specific attention as an equity theory in the literature, but nevertheless appears to have considerable support. This other theory is termed the noncompulsion equity theory for the purposes of this thesis. Despite the support from the accounting literature, it is shown that the non-compulsion equity theory appears to have little support from either the law or the economics literature. Given that accounting takes place in the wider legal and economic environment, this suggests that the non-compulsion equity theory may not be an appropriate basis for distinguishing between liabilities and equity. A review of the accounting conceptual statements reveals that they are inconsistent in their application of an underlying equity theory, because they use several equity theories rather than one, including the non-compulsion equity theory, which is adopted by the conceptual statements' definitions of liabilities and equity. A closer examination of the non-compulsion equity theory demonstrates that it is based upon inconsistent reasoning and questionable assumptions, suggesting that it is fundamentally flawed. This thesis concludes by rejecting the non-compulsion equity theory as a basis for distinguishing between liabilities and equity, suggesting that a new approach is required. The residual equity theory seems likely to provide a suitable alternative.

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  • Romantic relationships at work and attributions for the occupational success of participants

    McLaren, Elizabeth Sara (1994)

    Masters thesis
    University of Canterbury Library

    The research on romantic relationships at work was extended in two studies. In Study 1, 102 working people provided information about their experience of organisational romance in New Zealand. The results revealed many similarities to the findings of studies conducted in other countries. In Study 2, in an experiment, 144 students completed the Women as Managers Scale and made attributions for the promotion of stimulus managers who were involved in a workplace romance. As hypothesised, female subjects with more positive attitudes toward women in management tended to attribute the promotion of a female manager to internal factors rather than to external factors. Contrary to predictions, female managers were more favourably evaluated than male managers. However, as expected, there was a tendency for women to be more derogated than men for being romantically involved with a high status partner rather than a low status partner. The results were explained in relation to research on sex biases in evaluation. The implications of the findings for women and the management of organisational romance are discussed.

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  • Worker participation and worker privacy : a concern for managers planning office space?

    McMillan, Anna Natasha (1995)

    Masters thesis
    University of Canterbury Library

    Office space planning is a common occurrence in organisations, yet receives little attention in management and organisational theory. One possible explanation is that the physical work environment and its planning does not have a significant effect on worker attitudes and behaviour and therefore is not a priority for management practice. This is the interpretation of some early organisational studies which minimise the value of the physical environment as a management tool (e.g., as a "Hawthorne" effect or a "Hygiene factor"). These findings are thought to have contributed to the lack of attention to the physical work environment, including office space, in management theory and practice. However, the office space planning literature, which draws largely from the field of environmental design, suggests that office space planning should be of concern to managers. This thesis investigates this question. . Two aspects of office space planning were selected in order to explore this issue: office worker participation in planning and office worker privacy. Office worker participation was selected as an aspect of the process of planning and privacy because it was an outcome of planning. The practical application of the research question is investigated by analysing recent office space planning processes and outcomes occurring in seven organisations. Sources of data include the perceptions of office managers, office employees and one design professional gained from interviews, as well as written organisational records and floor plans. Key findings concerning participation included: while all managers interviewed had an ongoing and central role in office space planning, this role was new and they found little guidance available; managers were often not aware of their own decision making capability before they involved office workers in planning; poor liaison with those constructing the environment led to limitations in the way offices could be used; and perceived fairness in allocating space was important to office workers. Key findings on office worker privacy included: workers perceived privacy to be important to work related attitudes and behaviour; not having speech privacy or control over accessibility, distractions and interruptions was reported to effect work efficiency; and private interview rooms tend to be thought of as expansion space by managers in times of organisational change. On the basis of the analysis this study concludes that office space planning is deserving of further attention in management practice, research and theory.

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  • Pollen Dispersal Across the Southern Alps, South Island, New Zealand

    Randall, Paul M. (1990)

    Masters thesis
    University of Canterbury Library

    The aim of this research was to improve the understanding of modern pollen deposition in central South Island in order to interpret Quaternary pollen profiles. This was accomplished by examining the results from a chain of pollen traps (exposed for one year), moss polsters collected along a transect from Westland across the Southern Alps to Canterbury (with and without addition of exotic spores to facilitate 'absolute' counting) and three short peat monoliths. The role of topography, vegetation type and weather patterns were also briefly assessed. The results were analysed by means of principal components and cluster analyses to identify the respective contribution of different pollen taxa. The conclusions are: 1. Trap and polster results are broadly comparable. 2. With exceptions, caused by local effects such as fire and contributions by adjacent vegetation and taxa introduced since 1850, the monolith profiles show little change over the period studied. 3. Forest sites in Westland were dominated by pollen of local podocarps (Dacrydium cupressinum, Prumnopitys) and broadleaved angiosperm species (Metrosideros, Quintinia, Weinmannia). Nothofagus fusca type pollen dominates within the beech forest areas, but drops to about 10% a short distance from the forest edge. Poaceae pollen shows low frequencies in forested sites, but dominates in grass/scrubland areas. 4. Sites above the treeline on the Main Divide shows proportionately high counts of exogenous Podocarpaceae pollen. However, the high counts involve no 'real' increase in regional deposition.

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  • A Constitutive Model For Sandy Soils Based On A Stress-dependent Density Parameter

    Cubrinovski M (1993)

    Theses / Dissertations
    University of Canterbury Library

    The results of drained and undrained hollow cylinder tests on clean sand and sand with fines content of 10-15 % by weight constitute the basis for an investigation of the behaviour of sandy soils. An elastic-plastic constitutive model, which account for the combined influence of density and effective stress in a unique way, is developed. The study addresses many important issues relevant to sandy soil behaviour and represents a unite experimental and theoretical effort to develop a constitutive model for sandy soils comprising balanced features of accuracy, simplicity and versatility. Particular attention in both experimental and theoretical considerations is given to the effects of density and effective stress as well as their combined influence on the sandy soil behaviour. In general, two series of tests are performed, drained torsional shear tests and undrained torsional shear and torsional simple shear tests. Both series include monotonic and cyclic tests. The results of the drained torsional shear tests illustrated the effects of density and mean effective stress on the stress-strain and volume change behaviour of sandy soils and indicated that this behaviour is related to the relative initial state of the soil. The significance of the combined effects of density and effective stress is most profoundly illustrated by the measured identical stress-strain characteristics for quite different initial states including combinations of loose sand at low effective stress and dense sand at high effective stress. Another interesting observation is that stress-strain behaviour for the initial states above the threshold void ratio that indicates zero undrained residual strength, is practically independent of both density and effective stress. Thus, the threshold void ratio associated to zero undrained residual strength indicates the softest drained stress-strain behaviour for a given soil and initial fabric. Based on the experimental evidence obtained from the drained torsional shear tests, a plastic stress-strain relation with density-stress dependent parameters is developed. The parameters of this relation are expressed as functions of an index parameter established in the framework of the steady state of deformation concept. The parameter employed in the relation is the State Index I, which characterizes the sandy soil behaviour by accounting for the combined effects of density and effective stress related to a given initial fabric. The validity and the efficiency of the state index for representing drained sandy soil behaviour over a wide range of densities and effective stresses is assessed. The proposed stress-strain relation is a modified hyperbolic relation with the initial plastic modulus defined as a function of the plastic strain. Thus, it accounts for the greater nonlinearity than that provided by the two-constant hyperbolic relation and improves the accuracy of the stress-strain representation over the entire range of strains. The proposed stress-strain relation is characterized by a single set of coefficients for the entire range of densities and stresses. An elastic-plastic constitutive model is developed in the framework of the incremental theory of plasticity. The model is defined in a stress space that enables to account for the rotation of principal stresses and comprises: very small, in fact, 'point' yield surface with purely kinematic hardening rule; failure surface which incorporates the effects of density, effective stress and initial anisotropy, and which serves as bounding hardening surface and plastic potential; a set of four hardening surfaces in the memory with a rule for evaluation of the current hardening surface based on an assumption for mixed hardening; and plastic potential formulation providing noncoaxial and nonunique flow for all stress states except for those at failure. The accuracy and effectiveness of the elastic-plastic constitutive model is assessed through a comparison of the measured and predicted behaviour of sand in monotonic and cyclic, drained and undrained shear tests. The applicability of the model to seismic response analysis is demonstrated through blind-prediction of a seismic response of level ground model obtained from centrifuge test. Results of the element test simulations and blind-prediction of the response in the centrifuge tests have shown that the model is capable of representing drained and undrained, monotonic and cyclic behaviour with high degree of accuracy. Yet, that can be achieved with a single set of strength and deformation parameters over a wide range of densities and effective stresses.

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  • Torsion points on y²=x⁶+1

    Voloch JF (1997)

    Reports
    University of Canterbury Library

    Let C be the curve y²=x⁶+1 of genus 2 over a field of characteristic zero. Consider C embedded in its Jacobian J by sending one of the points at infinity on C to the origin of J. In this brief note we show that the points of C whose image on J are torsion are precisely the two points at infinity and the six points with y=0.

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  • Curves that change genus can have arbitrarily many rational points

    Voloch JF (1995)

    Reports
    University of Canterbury Library

    A singular curve over a non-perfect field K may not have a smooth model over K. Those are said to "change genus". If K is a global field of positive characteristic and C/K a curve that change genus, then C(K) is known to be finite. The purpose of this note is to give examples of curves with fixed relative genus, defined over K for which #C(K) is arbitrarily large. The motivation for considering this problem comes from the work of Caporaso et al. [CHM], where they show that a conjecture of Lang implies that, for a number field K, #C(K) can be bounded in terms of g and K only for all curves C/K of genus g > 1.

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  • "A colour line affair" : race, imperialism and rugby football contacts between New Zealand and South Africa to 1950.

    Buckley, Mike (1996)

    Masters thesis
    University of Canterbury Library

    This thesis is an attempt to construct an alternative tradition of New Zealand and South African rugby football contacts to 1950. It examines the wider social conditions of such contacts, unlike the existing plethora of rugby-centred chronicles of matches, tours, and sporting personalities. Rugby tours between New Zealand and South Africa before 1950 raised questions over the relationship between sport, race and imperialism. The manner that rugby reflected the divergent racial traditions in both societies thus challenges the cliche that sport is separate from wider social and political considerations. The thesis consists of an introduction, conclusion and four chapters. The chapters correlate with the New Zealand and South African rugby exchanges of 1921, 1928, 1937, and 1949. They are dominated by the themes of race relations and sporting imperialism, which form the context of the tours. Research is based on New Zealand newspaper sources; contextual material is derived from secondary sources.

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