12,117 results for 2000, University of Canterbury Library

  • Herschel-ATLAS: properties of dusty massive galaxies at low and high redshifts

    Rowlands, K.; Dunne, L.; Dye, S.; Aragon-Salamanca, A.; Maddox, S.; da Cunha, E.; Smith, D.J.B.; Bourne, N.; Eales, S.; Gomez, H.L.; Smail, I.; Alpaslan, M.; Clark, C.J.R.; Driver, S.; Ibar, E.; Ivison, R.J.; Robotham, A.; Smith, M.W.L.; Valiante, E. (2014)

    Journal Articles
    University of Canterbury Library

    We present a comparison of the physical properties of a rest-frame 250μm selected sample of massive, dusty galaxies from 0 < z < 5.3. Our sample comprises 29 high- redshift submillimetre galaxies (SMGs) from the literature, and 843 dusty galaxies at z < 0.5 from the Herschel -ATLAS, selected to have a similar stellar mass to the SMGs. The z > 1 SMGs have an average SFR of 390+80 −70M⊙yr−1 which is 120 times that of the low-redshift sample matched in stellar mass to the SMGs (SFR= 3.3 ± 0.2M⊙yr−1). The SMGs harbour a substantial mass of dust (1.2+0.3 −0.2×109M⊙), compared to (1.6± 0.1) × 108M⊙ for low-redshift dusty galaxies. At low redshifts the dust luminosity is dominated by the diffuse ISM, whereas a large fraction of the dust luminosity in SMGs originates from star-forming regions. At the same dust mass SMGs are offset towards a higher SFR compared to the low-redshift H-ATLAS galaxies. This is not only due to the higher gas fraction in SMGs but also because they are undergoing a more efficient mode of star formation, which is consistent with their bursty star-formation histories. The offset in SFR between SMGs and low-redshift galaxies is similar to that found in CO studies, suggesting that dust mass is as good a tracer of molecular gas as CO.

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  • Quantifying Spatial and Temporal Deposition of Atmospheric Pollutants in Runoff from Different Pavement Types

    Murphy, Louise Una (2015)

    Doctoral thesis
    University of Canterbury Library

    Urban development leads to increased impermeable landscapes that interrupt the hydrological cycle by creating an impermeable barrier to the natural infiltration of precipitation. Precipitate, unable to infiltrate, flows over impermeable surfaces as sheet runoff, carrying the pollutants from the land with it; thus comprising the quality of the stormwater. The runoff is redirected (frequently untreated) to nearby waterways altering their water quality and quantity, thereby, adversely affecting receiving aquatic ecosystems. Suspended solids and elevated heavy metal concentrations in stormwater are the leading causes of water quality degradation in urban waterways in New Zealand. It is widely reported that vehicles and metal roofs are a major direct source of the key pollutants (total suspended solids (TSS) and heavy metals) in stormwater runoff; however, the contribution of atmospheric deposition, as an indirect source, in stormwater runoff is rarely considered. This is principally due to the many uncertainties and challenges with measuring and managing these pollutants in stormwater runoff. Therefore, a monitoring programme into the dynamics controlling atmospherically derived pollutant build-up and wash-off from urban surfaces was conducted. In particular, this research focused on the spatial and temporal variability of Cu, Zn, Pb, and TSS deposition in different land-use areas; the influence of pavement type on atmospherically-deposited pollutant loads in stormwater; and the contribution of wet deposition and dry deposition to the total deposition loads. Impermeable concrete boards (≈ 1 m2) were deployed for 11 months in different land-use areas (industrial, residential and airside) in Christchurch, New Zealand, to capture spatially distributed atmospheric deposition loads in runoff over varying meteorological conditions. Mixed-effect regression models were developed to explain the influence of different meteorological characteristics on pollutant build-up and wash-off dynamics. Next, impermeable asphalt, permeable asphalt, impermeable concrete, and permeable concrete boards were deployed for two months in a residential land-use area to determine the influence of pavement composition and roughness on pollutant loads in stormwater. Finally, wet deposition samples were analysed in an industrial land-use area for 8 months to monitor the contribution of wet deposition to atmospherically-deposited pollutant loads. All samples were analysed for total and dissolved Cu, Zn, Pb, and TSS. Pavement type: Results showed that both impermeable and permeable concrete were efficient at retaining Cu and Zn. Bitumen leaching from the impermeable asphalt was a significant source of Zn to runoff. However, bitumen leaching from the permeable asphalt did not contain elevated Zn loads. Infiltrate from the permeable asphalt provided little/no removal of Cu and Zn. Impermeable asphalt provided greater retention of TSS and Pb over impermeable concrete because its rougher surface entrapped more particulates. TSS and Pb loads were the lowest from the permeable pavements due to the pavers filtering out particulates. Spatial variability: Results showed that all three land-use areas exhibited similar patterns of varying metal and TSS loads, indicating that atmospherically-deposited metals and TSS had a homogenous distribution within the Christchurch airshed. This suggested that the pollutants originated from a similar source and that the surrounding land-use was not an important factor in determining atmospheric pollutant loads to stormwater runoff. Although, higher pollutant loads were found for the industrial area, this was attributed to local topographic conditions rather than land-use activity. Temporal variability: Results illustrated the importance of antecedent dry days on pollutant build-up. Peak rainfall intensity and rain duration had a significant relationship with TSS and Pb wash-off; rain depth had a significant relationship with Cu and Zn wash-off. This suggested that the pollutant speciation phase plays an important role in surface wash-off. Rain intensity and duration influenced particulate pollutants, whereas, rain depth influenced dissolved pollutants. Additionally, mixed-effect models could predict approximately 53-69% of the variation in airborne pollutant loads in runoff. Deposition pathways: Wet deposition was an important contributor of dissolved Zn to stormwater runoff. However, dry deposition was the greatest source of total Cu, Zn, and Pb loads in stormwater runoff. This is principally due to the low annual rainfall in Christchurch limiting pollutant removal via wet deposition unlike dry deposition, which is continually occurring. Understanding the dynamics of airborne pollutant deposition and their contribution to stormwater pollution could help stormwater managers in strategic decision-making processes such as choice of location and installation of different treatment systems.

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  • A comparative study of mechanized cable harvesting systems in New Zealand

    Nuske, Samuel Ryan (2014)

    Bachelors thesis
    University of Canterbury Library

    Productivity and safety concerns of traditional cable harvesting systems have been the key drivers for increasing levels of mechanisation in New Zealand. The use of grapples in cable yarding could eliminate the need for motor-manual tree fallers and breaker-outs in most situations. A comparative time study was carried out on two mechanised cable harvesting systems utilising grapple carriages in an attempt to better understand the benefits and limitations of each system in different harvest settings. These systems include the Mechanical system which involved a swing yarder operating a mechanical grapple carriage and the Motorised system, which used a tower yarder with a motorised grapple carriage. The Mechanical system took less time to accumulate felled trees but took longer to unhook trees on the landing than the Motorised system. The Mechanical system had a shorter cycle time (2.07 minutes) than the Motorised system (2.32 minutes) and extracted 1.3 tonnes more than the Motorised system per cycle. The Motorised system had shorter cycle times when in horizontal haul distances of less than 90 metres, but had the longest times when the distance exceeded this. Utilisation rates were similar between the two systems, although the main difference in delays between the two systems was the use of surgepiles on the landing by the Motorised system. Both systems were effective, although on average the Mechanical system was more productive, with a productivity of 45 t/SMH, compared to 40 t/SMH for the Motorised system. The Mechanical system was the most productive when extracting mechanically felled and pre-bunched or trees while the Motorised system was the most productive when extracting motor-manually felled trees. Pre-bunching with an excavator was a more cost effective method than handing stems directly to the grapple carriage. Further research of the Mechanical system under more adverse conditions would allow a better overall comparison.

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  • Edaphic zoning and species-site matching to assist re-vegetation of indigenous species at the Styx Mill Reserve

    Campbell, Thornton (2014)

    Bachelors thesis
    University of Canterbury Library

    The Styx Mill Reserve is located in Belfast, Christchurch and is managed by the Christchurch City Council. Who aim to re-establish indigenous vegetation to large proportions of the area. These efforts have been successful in some sections of the Reserve; but large areas of the Reserve remain in grass and other weeds. The purpose of this investigation was to evaluate the presence of 5 hypothesised edaphic1 zones in a 10 ha study area, with a future aim of matching establishment practices to these edaphic sites. Findings indicated that all zones have significantly different vegetation and soil characteristics. Consequentially methods of native re-vegetation must be different in each zone if successful re-establishment of native species is to occur. Based on confirmed edaphic zones and client input, a site matched management plan and species list for one zone was developed. This aimed to increase the health and survival rates of plantings. Site modification followed techniques used at sites with similar conditions that have had successes in establishing woody vegetation. The effect of hydrogel on heath and survival levels was also trialled. To assess species suitability, five species were selected based on their abilities to survive the site conditions. Due to a combination of frost damage and ungulate browse, only totara survived and demonstrated good health scores. The frost factor is difficult to mitigate, hence species affected severely by frost are not recommended. The browse issue is easier to mitigate and it is felt that the two species heavily browsed, but not frosted are likely to be suitable. This resulted in ribbonwood, totara and kōhūhū being recommended. The time period did not allow assessment of the hydrogel treatment. Insufficient trial numbers exist to continue trials assessing future growth and survival rates over a longer time scale.

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  • The effect of plot co-registration error on the strength of regression between LiDAR canopy metrics and total standing volume in a Pinus radiata forest

    Slui, Benjamin Thomas (2014)

    Bachelors thesis
    University of Canterbury Library

    Background: The objective of this study was to verify the effect that plot locational errors, termed plot co-registration errors, have on the strength of regression between LiDAR canopy metrics and the measured total standing volume (TSV) of plots in a Pinus radiata forest. Methods: A 737 hectare plantation of mature Pinus radiata located in Northern Hawkes Bay was selected for the study. This forest had been measured in a pre-harvest inventory and had aerial LiDAR assessment. The location of plots was verified using a survey-grade GPS. Least square linear regression models were developed to predict TSV from LiDAR canopy metrics for a sample of 204 plots. The regression strength, accuracy and bias was compared for models developed using either the actual (verified) or the incorrect (intended) locations for these plots. The change to the LiDAR canopy metrics after the plot co-registration errors was also established. Results: The plot co-registration error in the sample ranged from 0.7 m to 70.3 m, with an average linear spatial error of 10.6 m. The plot co-registration errors substantially reduced the strength of regression between LiDAR canopy metrics and TSV, as the model developed from the actual plot locations had an R2 of 44%, while the model developed from the incorrect plot locations had an R2 of 19%. The greatest reductions in model strength occurred when there was less than a 60% overlap between the plots defined by correct and incorrect locations. Higher plot co-registration errors also caused significant changes to the height and density LiDAR canopy metrics that were used in the regression models. The lower percentile elevation LiDAR metrics were more sensitive to plot co- registration errors, compared to higher percentile metrics. Conclusion: Plot co-registration errors have a significant effect on the strength of regressions formed between TSV and LiDAR canopy metrics. This indicates that accurate measurements of plot locations are necessary to fully utilise LiDAR for inventory purposes in forests of Pinus radiata.

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  • Forest Industry Employees: training, safety and retention

    Muir, Kate Rosemary (2014)

    Bachelors thesis
    University of Canterbury Library

    Forestry employees are the most valuable asset to forest operations. An analysis was completed to determine employee training status, how safe employees feel within their roles and identify major reasons of dissatisfaction. Through the development of job descriptions and person specifications, it was possible to identify the job requirements along with the personal attributes and qualifications required by employers, to ensure employees were capable of undertaking their role. There is an identifiable gap within the level of formal education among employees. Over half (55%) of the employees have lower qualifications than those required to have undertaken further forestry on-job training. A majority of employees’, particularly those in machine operator roles feel safe in their forestry operational roles. A small proportion of employees in breaker out, thin to waste and pruning roles feel unsafe. All employees surveyed except loader operators, felt only moderately safe in their role. The difficult environment associated with forestry was determined to be the major reason for dissatisfaction (52%) among employees, along pay and length of day. Paradoxically, the environment was also a major reason for satisfaction among those surveyed. By identifying the major reasons of dissatisfaction among forestry employees it is possible to improve job satisfaction and employee retention. Training forestry employees needs to be from a more practical aspect. This will lead to increase the number of employees that are trained for the roles they are undertaking, by ensuring they are equipped with adequate knowledge, and have the skill to work safely and to a high quality standard.

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  • Dynamic behaviour of brain and surrogate materials under ballistic impact

    Soltanipour Lazarjan, Milad (2015)

    Doctoral thesis
    University of Canterbury Library

    In the last several decades the number of the fatalities related to criminally inflicted cranial gunshot wounds has increased (Aarabi et al.; Jena et al., 2014; Mota et al., 2003). Back-spattered bloodstain patterns are often important in investigations of cranial gunshot fatalities, particularly when there is a doubt whether the death is suicide or homicide. Back-spatter is the projection of blood and tissue back toward the firearm. However, the mechanism of creation of the backspatter is not understood well. There are several hypotheses, which describe the formation of the backspatter. However, as it is difficult to study the internal mechanics of formation of the backspatter in animal experiments as the head is opaque and sample properties vary from animal to animal. Performing ballistic experiments on human cadavers is rarely not possible for ethical reasons. An alternative is to build a realistic physical 3D model of the human head, which can be used for reconstruction of crime scenes and BPA training purposes. This requires a simulant material for each layer of the human head. In order to build a realistic model of human head, it is necessary to understand the effect of the each layer of the human head to the generation of the back-spatter. Simulant materials offer the possibility of safe, well‐controlled experiments. Suitable simulants must be biologically inert, be stable over some reasonable shelf‐life, and respond to ballistic penetration in the same way as the responding human tissues. Traditionally 10-20% (w/w) gelatine have been used as a simulant for human soft tissues in ballistic experiments. However, 10-20% of gelatine has never been validated as a brain simulant. Moreover, due to the viscoelastic nature of the brain it is not possible to find the exact mechanical properties of the brain at ballistic strain rates. Therefore, in this study several experiments were designed to obtain qualitative and quantitative data using high speed cameras to compare different concentrations of gelatine and new composite material with the bovine and ovine brains. Factors such as the form of the fragmentation, velocity of the ejected material, expansion rate, stopping distance, absorption of kinetic energy and effect of the suction as well as ejection of the air from the wound cavity and its involvement in the generation of the backspatter have been investigated. Furthermore, in this study a new composite material has been developed, which is able to create more realistic form of the fragmentation and expansion rate compared to the all different percentage of the gelatine. The results of this study suggested that none of the concentrations the gelatine used in this study were capable of recreating the form of the damage to the one observed from bovine and ovine brain. The elastic response of the brain tissue is much lower that observed in gelatine samples. None of the simulants reproduced the stopping distance or form of the damage seen in bovine brain. Suction and ejection of the air as a result of creation of the temporary cavity has a direct relation to the elasticity of the material. For example, by reducing the percentage of the gelatine the velocity of the air drawn into the cavity increases however, the reverse scenario can be seen for the ejection of the air. This study showed that elastic response of the brain tissue was not enough to eject the brain and biological materials out of the cranium. However, the intracranial pressure raises as the projectile passes through the head. This pressure has the potential of ejecting the brain and biological material backward and create back-spatter. Finally, the results of this study suggested that for each specific type of experiment, a unique simulant must be designed to meet the requirements for that particular experiment.

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  • Measuring Trust for Crowdsourced Geographic Information

    Severinsen, Jeremy John (2015)

    Masters thesis
    University of Canterbury Library

    In recent years Crowdsourced, or Volunteered, Geographic Information (CGI, VGI), has emerged as a large, up-to-date and easily accessible data source. Primarily attributable to the rise of the Geoweb and widespread use of location enabled technologies, this environment of widespread innovation has repositioned the role of consumers of spatial information. Collaborative and participatory web environments have led to a democratisation of the global mapping process, and resulted in a paradigm shift to the consumer of geographic data also acting as a data producer. With such a large and diverse group of participants actively mapping the globe, the resulting flood of information has become increasingly attractive to authoritative mapping agencies, in order to augment their own spatial data supply chains. The use of CGI would allow these agencies to undertake continuous improvement of their own data and products, adding a dimension of currency that has previously been unattainable due to high associated costs. CGI, however, through its diversity of authorship, presents a quality assurance risk to these agencies should it be included in their authoritative products. Until now, this risk has been insurmountable, with CGI remaining a “Pandora’s Box” which many agencies are reluctant to open. This research presents an algorithmic model that overcomes these issues, by quantifying trust in CGI in order to assess its implied quality. Labeled “VGTrust”, this model assesses information about a data author, its spatial trust, as well as its temporal trust, in order to produce an overall metric that is easy to understand and interpret. The VGTrust model will allow mapping agencies to harness CGI to augment existing datasets, or create new ones, thereby facilitating a targeted quality assurance process and minimizing risk to authoritativeness. This research proposes VGTrust in theory, on the basis of existing examinations of trust issues with CGI. Furthermore, a facilitated case study, “Building Our Footprints” is presented, where VGTrust is deployed to facilitate the capture of a building footprint dataset, the results of which revealing the veracity of the model as a measure to assess trust for these data. Finally, a data structure is proposed in the form of a “geo-molecule”, which allows the full spectrum of trust indicators to be stored a data structure at feature level, allowing the transitivity of this information to travel with each feature following creation. By overcoming the trust issues inherent in CGI, this research will allow the integration of crowdsourced and authoritative data, thereby leveraging the power of the crowd for productive and innovative re-use.

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  • Citizenship education and ‘Bildung’: Learning from “the Norwegian way” : a case study of teaching and learning democracy in a Norwegian junior high school.

    Plew, Elizabeth (2014)

    Masters thesis
    University of Canterbury Library

    How citizenship is taught in schools can have a profound impact on the development of young people’s ability and willingness to participate in public life. In turn, citizen participation has significant consequences for the health of a country’s democracy (Levine, 2003, Torney-Purta and Richardson, 2004, Osler and Starkey, 2006, Chawla, 2009, Hayward, 2012). Many established democracies today struggle with declining youth voter turnout and civic engagement (Levine, 2003, Catt, 2005, Gallego, 2009, Vowles, 2010, Blais and Rubenson, 2013). However Norway differs from many other democracies in that Norwegian students have one of the highest comparative rates of participation in different civic activities at school (Schulz et al., 2010). To help shed light on why Norway has been so effective at engaging young people in civic life, this thesis examined how democracy is taught in a Norwegian junior high school (ungdomsskole). The results of classroom observation, along with interviews with pupils, parents, administrators and teachers, indicate that deeply-held beliefs about the value of democracy underpin teacher practice alongside strong societal and parent support for citizenship education. This in-depth case study highlights the importance of a teaching philosophy based on a Norwegian interpretation of Bildung, an approach to education of the individual through discussion and action, so that individuals come to understand how they can contribute as citizens to the wider Norwegian polity. The case study suggests that the values of Bildung implicitly inform approaches of participatory learning, deliberation and teachers’ relationships with students, in ways which support young people as they in turn learn to value democracy. The research concludes that these experiences help to equip the ungdomsskole students observed in this case study with skills that they can use both immediately and in the future to participate as citizens in democratic processes and decision-making.

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  • CPT Prediction of Soil Behaviour Type, Liquefaction Potential and Ground Settlement in North-West Christchurch

    Van T Veen, Lauren Hannah (2015)

    Masters thesis
    University of Canterbury Library

    As a consequence of the 2010 – 2011 Canterbury earthquake sequence, Christchurch experienced widespread liquefaction, vertical settlement and lateral spreading. These geological processes caused extensive damage to both housing and infrastructure, and increased the need for geotechnical investigation substantially. Cone Penetration Testing (CPT) has become the most common method for liquefaction assessment in Christchurch, and issues have been identified with the soil behaviour type, liquefaction potential and vertical settlement estimates, particularly in the north-western suburbs of Christchurch where soils consist mostly of silts, clayey silts and silty clays. The CPT soil behaviour type often appears to over-estimate the fines content within a soil, while the liquefaction potential and vertical settlement are often calculated higher than those measured after the Canterbury earthquake sequence. To investigate these issues, laboratory work was carried out on three adjacent CPT/borehole pairs from the Groynes Park subdivision in northern Christchurch. Boreholes were logged according to NZGS standards, separated into stratigraphic layers, and laboratory tests were conducted on representative samples. Comparison of these results with the CPT soil behaviour types provided valuable information, where 62% of soils on average were specified by the CPT at the Groynes Park subdivision as finer than what was actually present, 20% of soils on average were specified as coarser than what was actually present, and only 18% of soils on average were correctly classified by the CPT. Hence the CPT soil behaviour type is not accurately describing the stratigraphic profile at the Groynes Park subdivision, and it is understood that this is also the case in much of northwest Christchurch where similar soils are found. The computer software CLiq, by GeoLogismiki, uses assessment parameter constants which are able to be adjusted with each CPT file, in an attempt to make each more accurate. These parameter changes can in some cases substantially alter the results for liquefaction analysis. The sensitivity of the overall assessment method, raising and lowering the water table, lowering the soil behaviour type index, Ic, liquefaction cutoff value, the layer detection option, and the weighting factor option, were analysed by comparison with a set of ‘base settings’. The investigation confirmed that liquefaction analysis results can be very sensitive to the parameters selected, and demonstrated the dependency of the soil behaviour type on the soil behaviour type index, as the tested assessment parameters made very little to no changes to the soil behaviour type plots. The soil behaviour type index, Ic, developed by Robertson and Wride (1998) has been used to define a soil’s behaviour type, which is defined according to a set of numerical boundaries. In addition to this, the liquefaction cutoff point is defined as Ic > 2.6, whereby it is assumed that any soils with an Ic value above this will not liquefy due to clay-like tendencies (Robertson and Wride, 1998). The method has been identified in this thesis as being potentially unsuitable for some areas of Christchurch as it was developed for mostly sandy soils. An alternative methodology involving adjustment of the Robertson and Wride (1998) soil behaviour type boundaries is proposed as follows:  Ic < 1.31 – Gravelly sand to dense sand  1.31 < Ic < 1.90 – Sands: clean sand to silty sand  1.90 < Ic < 2.50 – Sand mixtures: silty sand to sandy silt  2.50 < Ic < 3.20 – Silt mixtures: clayey silt to silty clay  3.20 < Ic < 3.60 – Clays: silty clay to clay  Ic > 3.60 – Organics soils: peats. When the soil behaviour type boundary changes were applied to 15 test sites throughout Christchurch, 67% showed an improved change of soil behaviour type, while the remaining 33% remained unchanged, because they consisted almost entirely of sand. Within these boundary changes, the liquefaction cutoff point was moved from Ic > 2.6 to Ic > 2.5 and altered the liquefaction potential and vertical settlement to more realistic ii values. This confirmed that the overall soil behaviour type boundary changes appear to solve both the soil behaviour type issues and reduce the overestimation of liquefaction potential and vertical settlement. This thesis acts as a starting point towards researching the issues discussed. In particular, future work which would be useful includes investigation of the CLiq assessment parameter adjustments, and those which would be most suitable for use in clay-rich soils such as those in Christchurch. In particular consideration of how the water table can be better assessed when perched layers of water exist, with the limitation that only one elevation can be entered into CLiq. Additionally, a useful investigation would be a comparison of the known liquefaction and settlements from the Canterbury earthquake sequence with the liquefaction and settlement potentials calculated in CLiq for equivalent shaking conditions. This would enable the difference between the two to be accurately defined, and a suitable adjustment applied. Finally, inconsistencies between the Laser-Sizer and Hydrometer should be investigated, as the Laser-Sizer under-estimated the fines content by up to one third of the Hydrometer values.

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  • The Prevalence of Aspiration Pneumonia in Rest Home Residents with Reduced Cough Reflex Sensitivity

    Cossou, Warren (2015)

    Masters thesis
    University of Canterbury Library

    The aim of this study was to determine whether there was an association between a failed test of cough reflex sensitivity and history of chest infection in a general population of rest home residents. One hundred rest home residents from four different levels of care (rest home, hospital, dementia and psycho-geriatric) were recruited and their cough reflex assessed using a solution of 0.6 Mol/L citric acid nebulised and presented via a facemask.Participant’s records were then checked to see if there were any documented episodes of chest infection in the 6 month period prior to cough reflex testing.The results showed that out of 100 participants, 4 failed the cough reflex test. Of the 4 that failed the test, 3 had no documented episodes of chest infections recorded in the 6 month period prior to cough reflex testing. Data was not available for one participant who was deceased by the time of collection of the second data set. As such, there was no direct association demonstrated between a failed cough reflex test and development of chest infection or aspiration pneumonia. The results of the study are unexpected in two ways. Firstly, the relatively low number of participants who failed the cough reflex test is surprising as 72% of the participants for whom a full data set was obtained had neurological conditions that are known predisposing factors for reduced cough reflex sensitivity. Secondly, the finding of no association between a failed cough reflex test and history of recorded chest infection is not consistent with other studies. There is however an established body of research that indicates the causes of aspiration pneumonia are multifactorial and not solely dependent upon aspiration. The characteristics of participants and the implications of the findings are described. The potential use of cough reflex testing as a tool to screen against the risks of silent aspiration in relation to assessment of oro-pharyngeal dysphagia in this frail, elderly population is discussed.

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  • Allosteric Regulation of the First Enzyme in Histidine Biosynthesis

    Livingstone, Emma Kathrine (2015)

    Masters thesis
    University of Canterbury Library

    The ATP-PRTase enzyme catalyses the first committed step of histidine biosynthesis in archaea, bacteria, fungi and plants.1 As the catalyst of an energetically expensive pathway, ATP-PRTase is subject to a sophisticated, multilevel regulatory system.2 There are two families of this enzyme, the long form (HisGL) and the short form (HisGS) that differ in their molecular architecture. A single HisGL chain comprises three domains. Domains I and II house the active site of HisGL while domain III, a regulatory domain, forms the binding site for histidine as an allosteric inhibitor. The long form ATP-PRTase adopts a homo-hexameric quaternary structure.3,4 HisGS comprises a similar catalytic core to HisGL but is devoid of the regulatory domain and associates with a second protein, HisZ, to form a hetero-octameric assembly.5 This thesis explores the allosteric regulation of the short form ATP-PRTase, as well as the functional and evolutionary relationship between the two families. New insight into the mode allosteric inhibition of the short form ATP-PRTase from Lactococcus lactis is reported in chapter two. A conformational change upon histidine binding was revealed by small angle X-ray scattering, illuminating a potential mechanism for the allosteric inhibition of the enzyme. Additionally, characterisation of histidine binding to HisZ by isothermal titration calorimetry, in the presence and absence of HisGS, provided evidence toward the location of the functional allosteric binding site within the HisZ subunit. Chapter three details the extensive effort towards the purification of the short form ATP-PRTase from Neisseria menigitidis, the causative agent of bacterial meningitis. This enzyme is of particular interest as a potential target for novel, potent inhibitors to combat this disease. The attempts to purify the long form ATP-PRTase from E. coli, in order to clarify earlier research on the functional multimeric state of the enzyme, are also discussed. Chapter four reports the investigation of a third ATP-PRTase sequence architecture, in which hisZ and hisGS comprise a single open reading frame, forming a putative fusion enzyme. The engineering of two covalent linkers between HisZ and HisGS from L. lactis and the transfer of the regulatory domain from HisGL to HisGS, is also discussed, in an attempt to delineate the evolutionary pathway of the ATP-PRTase enzymes. Finally, the in vivo activity of each functional and putative ATP-PRTase was assessed by E. coli BW25113∆hisG complementation assays.

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  • Inverse problems in astronomical imaging

    Johnston, Rachel Anne (2000)

    Doctoral thesis
    University of Canterbury Library

    The imaging of astronomical objects is limited by atmospheric turbulence, which consists of layers of varying refractive index surrounding the earth. These refractive index fluctuations are a direct consequence of the warming and cooling of air and water vapour in the atmosphere. Wavefronts entering the atmosphere acquire phase distortions, which when propagated result in amplitude fluctuations known as scintillation. Hence the practical manifestation of the atmosphere is a degradation of the signals passing through it, for example it severely limits the resolution of images captured by ground-based telescopes. A variety of solutions, or inverse problems, have been proposed and trialed in the attempt to obtain the best possible images from astronomical telescopes. An orbiting telescope (for example the Hubble space telescope) is one solution. In this case light is captured before it is distorted by the atmosphere. Less expensive ground-based solutions include the post processing of short exposure images and real-time compensation using adaptive optics, both of which are investigated in this thesis. However, the success of an inverse problem lies in the accurate modelling of the processes that give rise to the corresponding forward problem, in this case the random refractive index fluctuations that characterise the atmosphere. Numerical simulation of atmospheric turbulence is achieved using phase screens in which the assumption of Kolmogorov statistics is often made. A previously presented method for modelling Kolmogorov phase fluctuations over a finite aperture, the midpoint displacement method, is both formalised and improved. This enables the accurate generation of atmospheric speckle images for the development and testing of post processing methods. Another aspect of the forward problem is the accurate simulation of scintillation, resulting from the propagation of phase distorted wavefronts. Commonly used simulation methods achieve this by assuming periodic boundary conditions. A technique for the accurate modelling and simulation of scintillation from an aperiodic Kolmogorov phase screen is presented. The more physically justifiable assumption of smoothness is shown to result in a propagation kernel of finite extent. This allows the phase screen dimensions for an accurate simulation to be determined and truncation can then be used to eliminate the unwanted spectral leakage and diffraction effects usually inherent in the use of finite apertures. Deconvolution methods are popular for the post processing of atmospheric speckle images to compensate for the effects of the atmosphere. Conventional deconvolution algorithms are applied when the distortion is known or well-characterised, whereas, blind deconvolution algorithms are used when the distortion is unknown. Conventional deconvolution techniques are not often directly applied to astronomical imaging problems as the distortion introduced by the atmosphere is unknown. However, their extension to blind deconvolution is straightforward and hence their development is valuable. The ill-conditioning of the deconvolution problem requires the addition of prior information, such as positivity, to enable its solution. It is shown that the conventional deconvolution problem can be reformulated as an equivalent quadratic programming problem. Consequently, an accelerated quadratic programming approach is applied and shown to be an improvement to an existing method used for enforcing positivity in deconvolution applications. The main algorithmic differences of the new method are implementation via the fast Fourier transform (FFT) and guaranteed convergence to the constrained minimum. Blind deconvolution is also an interesting problem that may arise in many fields of research. It is of particular relevance to imaging through turbulence where the point spread function can only be modelled statistically, and direct measurement may be difficult. The extension of the quadratic programming method to blind deconvolution, combined with Tikhonov-Miller regularisation (energy constraints), smoothness constraints, penalty terms and statistical priors produced a series of new algorithms. The performance of these algorithms is illustrated on simulated astronomical speckle images. Ground-based adaptive optics (AO) technologies are an alternative to post processing methods and aim to compensate for the distortion introduced by the atmosphere in real-time. Knowledge of the vertical structure of the atmosphere combined with AO provides the potential for compensation over a wide field of view. However, the continually changing nature of atmospheric turbulence places strict requirements on techniques for determining the turbulence structure. The remote sensing of scintillation data to estimate this information is known as scintillation detection and ranging (SCIDAR). Application of SCIDAR methods to the capture and analysis of experimental data, as demonstrated in this thesis, highlighted a number of problems with the technique. Methods for overcoming these difficulties are discussed and demonstrated. Finally, alternative approaches to the estimation of atmospheric turbulence profiles and a proposed new technique are investigated.

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  • Assessment of the Opportunity of Modern Cable Yarders for Application in New Zealand

    Campbell, Thornton (2016)

    Masters thesis
    University of Canterbury Library

    This study examined the opportunity of implementing modern yarder machinery to increase the productivity and worker safety of cable logging operations within New Zealand. Cable yarding equipment used in New Zealand is generally based on designs from pre-1980 with the majority of the machines built around that time in the Pacific Northwest, USA. New yarder designs have a number of features that may give them an advantage, including being; smaller, quieter, more fuel efficient, safer and more ergonomic to operate. These benefits can be of even greater value as the forest industry transitions from predominantly larger scale commercial plantations, to a significant proportion of woodlot scale operations. Field studies ranging from three to five day of duration were carried out on three new machines believed to have potential in New Zealand; the Active 70 at two locations in the central North Island region of New Zealand, the Koller 602h in the Gisborne region of New Zealand and for comparison the Koller 507 in Austria. The studies focussed on assessing productivity and ergonomic advantages. Productivity was measured with a time and motion study and the potential ergonomic advantages were assessed using choker-setter heart rates and machine noise emissions. The time and motion study found a productivity level for the Active 70 of 23.5m3/SMH with a utilisation rate of 65% at site one and 24.5m3/SMH at a utilisation rate of 76% for site two. The productivity for the Koller 602h was 21.0m3/SMH at an utilisation rate of 55% and 7.9m3/SMH for the Koller 507 at an utilisation rate of 55%. Productivity was deemed to be negatively impacted by poor site conditions for the Active 70 and Koller 507, and utilisation was low for the Koller 602h which was mainly attributed to the lack of crew experience with the new machine. Choker-setter heart rate results showed choker-setters to be working at the level of ‘hard continuous work’ (‘relative heart rate at work’ over 30%, but less than 40%). In this study the motorised carriage used at the first Active 70 study site offered no ergonomic advantages over the traditional North Bend system at the second site. Decibel analysis found that the modern equipment was significantly quieter, resulting in smaller zones in which hearing protection is required. In particular, the Koller K602hrecorded 70dB at 5 meters during operation, well below the 85dB level that is common recognised as the decibel threshold for hearing damage. During these case studies the machines all operated below the average New Zealand productivity rate of 26.3m3/SMH and no clear ergonomic advantage was established for the choker-setters. As such these machines are not likely to out-compete existing machinery choices in either productivity or choker-setter work rate. However, cost-benefit analyses were not possible because of limited information about operating cost and the absence of truly comparable settings. Advantages such as the advanced control systems and lower noise levels, while still achieving respectable productivity figures, indicate that they are viable alternatives for New Zealand cable yarding if applied correctly.

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  • Effective use of Technologies in the Classroom

    White, Annabelle (2016)

    Journal Articles
    University of Canterbury Library

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  • Interdisciplinary Team Teaching to support 21st Century Learning Skills

    Buick, Danielle (2016)

    Journal Articles
    University of Canterbury Library

    There is a need to reimagine education in the New Zealand secondary school context that better supports twenty-first century learning skills. Interdisciplinary team teaching provides a model of change that could enable schools to reimagine how education is delivered, how knowledge is created, and better exemplify and incorporate learning skills relevant to a rapidly developing world. This article explores primarily qualitative data drawn from research addressing interdisciplinary team teaching (ITT) that spans across primary to tertiary settings in a range of contexts. The findings from this research express why it is necessary to reimagine current education systems, the benefits and barriers of ITT, and what enables the successful implementation of ITT. If a school is able to negotiate the barriers and understand what is necessary to make it work then research suggests that ITT can provide a structural, pedagogical, and philosophical change that will enhance learning skills necessary for the twenty-first century world.

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  • Editorial, Volume 2, November 2016

    Astall, Chris; Fastier, Murray; Lewis, Trish; Graham, James (2016)

    Journal Articles
    University of Canterbury Library

    Welcome to the second issue of the Journal of Initial Teacher Inquiry. This journal celebrates inquiry based research as conducted by Initial Teacher Education (ITE) students completing the intensive, one year Master of Teaching and Learning (MTchgLn) course at the University of Canterbury, Christchurch, New Zealand. Our MTchgLn programme whakataukī emphasises the value we place on our ITE students and their learning; Ahakoa he iti, he pounamu - Although it is small, it is greenstone

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  • Mentor and Student Teacher Relationship Factors During Placement

    Bodger, Glenn (2016)

    Journal Articles
    University of Canterbury Library

    This article discusses findings from research concerning the expectations and perceptions of mentor teachers and student teachers (mentees), and how communication may affect this mentor-mentee relationship. The research points to the mentor-mentee relationships as pivotal in the development of student teachers. Findings show that expectations and perceptions of the roles require clarity from both mentor teacher and student teacher perspectives, and with more explicit communication there is an increased likelihood of building positive relationships. It is crucial that communication occurs from the beginning of the mentor-mentee relationship. The research examined also identified significant differences in the messages being communicated between the partners in the mentor-mentee relationship when student teachers are mentored in pairs, as opposed to one on one mentoring. The change in dynamics with paired placements may also lead to a more teaching focussed experience with reduced pressure on the individual student teacher.

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  • The impact of heavy metals on benthic macroinvertebrate communities in Christchurch's urban waterways

    Eden, Jason Scott (2016)

    Masters thesis
    University of Canterbury Library

    The urbanisation of a catchment results in substantial changes to associated waterways. These effects, known as the “urban stream syndrome” can include flashier hydrographs due to stormwater inflows, altered geomorphology, and increased inputs of sediment, nutrients, and toxicants. Metal pollution of rivers and streams is an area of significant concern for management of freshwaters, and urban runoff is recognised as an increasingly relevant source of metals. Heavy metals can to be toxic to aquatic invertebrates, and can impact community structure and abundance. To investigate the influence of heavy metals on macroinvertebrate community composition, I compared invertebrate community composition over a gradient of heavy metal pollution within Christchurch City’s urban waterways. I also investigated the survival of three taxa, the mayfly Deleatidium spp., the caddisfly Pycnocentria spp., and the snail Potamopyrgus antipodarum in short-term in situ mesocosm experiments in six streams of varying metal contamination. CCA analysis identified that sediment bound metals, dissolved metals, and impervious surface area were the three most significant environmental factors explaining invertebrate community structure. Stepwise regression analysis of invertebrate community metrics and indices identified metals bound to the sediment to be among the prevailing factors in explaining invertebrate community composition across my study sites. The results of my mesocosm experiments suggest that heavy metal contamination could be rendering more impacted streams uninhabitable to relatively sensitive taxa (such as Deleatidium and Pycnocentria). However, over the seven day time frame of my mesocosm experiment, conditions in moderately polluted streams did not appear to directly affect survival of Deleatidium significantly more than conditions in streams containing natural populations of the mayfly. Knowledge of relevant stressors is key to the management and rehabilitation of urban streams. My results suggest that heavy metals are likely a key stressor on many invertebrate communities in Christchurch’s urban waterways. While rehabilitation of streams in Christchurch’s heavily urbanised areas can improve attractiveness and societal value, unless stormwater inputs and associated pollutants are mitigated an improvement in biological communities seems unlikely.

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  • Journal of Initial Teacher Inquiry, Volume 2 November 2016 

    Compton, Jessica; Buick, Danielle; Bodger, Glenn; White, Annabelle; Edmunds, Catherine; FitzGerald, Bethan; Reveley, Emma; van Gelder-Horgan, Karen; Wilson, Dan; Dickson, Madeleine; Thomas, Julie; Pavelka, Ariana (2016)

    Journal Articles
    University of Canterbury Library

    Welcome to the second issue of the Journal of Initial Teacher Inquiry. This journal celebrates inquiry based research as conducted by Initial Teacher Education (ITE) students completing the intensive, one year Master of Teaching and Learning (MTchgLn) course at the University of Canterbury, Christchurch, New Zealand. Our MTchgLn programme whakataukī emphasises the value we place on our ITE students and their learning; Ahakoa he iti, he pounamu - Although it is small, it is greenstone.

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