80,754 results

  • Complex Recombination Patterns Arising during Geminivirus Coinfections Preserve and Demarcate Biologically Important Intra-Genome Interaction Networks

    Martin, D.P.; Lefeuvre, P.; Varsani, A.; Hoareau, M.; Semegni, J.Y.; Dijoux, B.; Vincent, C.; Reynaud, B.; Lett, J-M. (2011)

    Journal Articles
    University of Canterbury Library

    Genetic recombination is an important process during the evolution of many virus species and occurs particularly frequently amongst begomoviruses in the single stranded DNA virus family, Geminiviridae. As in many other recombining viruses it is apparent that non-random recombination breakpoint distributions observable within begomovirus genomes sampled from nature are the product of variations both in basal recombination rates across genomes and in the over-all viability of different recombinant genomes. Whereas factors influencing basal recombination rates might include local degrees of sequence similarity between recombining genomes, nucleic acid secondary structures and genomic sensitivity to nuclease attack or breakage, the viability of recombinant genomes could be influenced by the degree to which their co-evolved protein-protein and protein-nucleotide and nucleotide-nucleotide interactions are disreputable by recombination. Here we investigate patterns of recombination that occur over 120 day long experimental infections of tomato plants with the begomoviruses Tomato yellow leaf curl virus and Tomato leaf curl Comoros virus. We show that patterns of sequence exchange between these viruses can be extraordinarily complex and present clear evidence that factors such as local degrees of sequence similarity but not genomic secondary structure strongly influence where recombination breakpoints occur. It is also apparent from our experiment that over-all patterns of recombination are strongly influenced by selection against individual recombinants displaying disrupted intra-genomic interactions such as those required for proper protein and nucleic acid folding. Crucially, we find that selection favoring the preservation of co-evolved longer-range proteinprotein and protein DNA interactions is so strong that its imprint can even be used to identify the exact sequence tracts involved in these interactions.

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  • Earthquakes, Trees, and the 'New Normal'

    Morgenroth, J. (2011)

    Conference Contributions - Other
    University of Canterbury Library

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  • Development of Passive Treatment Systems for Treating Acid Mine Drainage at Stockton Mine

    McCauley, C.; O'Sullivan, A.D.; Weber, P.; Trumm, D. (2008)

    Conference Contributions - Published
    University of Canterbury Library

    Acid mine drainage (AMD) at Stockton Coal Mine is generated from the oxidation of pyrite in carbonaceous mudstones exposed during surface mining. Acidity production causes metals such as Fe and Al to leach from overburden materials including feldspars. Water chemistry and flow were monitored at numerous AMD seeps at Stockton. Manchester Seep, which daylights at the toe of an overburden embankment, was identified as a suitable research site for trialling passive-treatment systems designed to neutralize acidity and sequester metals in AMD. Median dissolved metal concentrations from the Manchester seep were; 62.9 mg/L Fe, 32.5 mg/L Al, 0.0514 mg/L Cu, 0.175 mg/L Ni, 0.993 mg/L Zn and 0.00109 mg/L Cd. Treatment of this water is achieved downstream by the Mangatini fine limestone dosing plant, however in the interest of assessing other technologies this work investigated the use of bioreactors to assess the potential of passive treatment technologies to treat the Manchester Seep AMD. Geotechnical parameters, including hydraulic conductivity, were measured for various mixtures of organic and alkaline waste products suitable for use as bioreactor media. Seven mesocosm-scale bioreactors were fed aerated Manchester Seep AMD in a laboratory set-up for nearly four months. Bioreactors incorporating mussel shells performed better than limestone and were capable of sequestering >0.80 mol metals/m3 substrate/day (or neutralising acidity at rates >66 g CaCO3/m2/day) while removing >98.2% of all metals. Tracer studies were conducted on two bioreactor systems containing the same substrate composition but different reactor shapes. Results will be applied to reactor models to better ascertain the relationship between reactor hydraulics and treatment performance. Pilot-scale passive systems incorporating three treatment stages were designed and are currently being installed to treat a portion of Manchester Seep AMD on site. The first stage consists of a sedimentation basin to remove sediment. The second stage includes three bioreactors in parallel to test treatment effectiveness of different substrate mixtures, depths and hydraulic configurations. Data derived from the mesocosm lab study were used to optimise these designs. The final treatment stage consists of three different aerobic wetland configurations, also operated in parallel, to compare their effectiveness at providing oxygenation and tertiary treatment of metals (primarily Fe) from bioreactor effluent.

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  • A landscape approach to assess impacts of hydrological changes to vegetation communities of the Tonle Sap Floodplain

    Arias, M.E.; Cochrane, T.A.; Caruso, B.; Killeen, T.; Kummu, M. (2011)

    Conference Contributions - Published
    University of Canterbury Library

    The Tonle Sap is South East Asia’s largest lake and Cambodia’s most important fishery. The hydrology of the Tonle Sap is directly linked to water levels of the Mekong River, which will experience major alterations as a response to hydropower development, irrigation, and climate change. This paper proposes a landscape approach to understand the impacts of hydrological alteration on the floodplain’s terrestrial vegetation. A land cover map, a digital elevation map and historical water records were used to create histograms of water depth for key vegetation communities. These histograms were used to create maps of vegetation coverage probability for future scenarios of hydrological changes. Selected scenarios of water resources development and climate change were used to demonstrate how vegetation could shift within the floodplain. This approach generated satisfactory results for land cover classes that extend over large portions of the floodplain such as wet season rice, abandoned fields, flooded shrubland and open lake.

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  • Digital transmission: Spectrally efficient techniques

    Henderson, Brian Gordon (1984)

    Doctoral thesis
    University of Canterbury Library

    Spectrally efficient methods of digital transmission are studied, with particular emphasis on vestigial sideband (VSB) signalling. A general overview of digital transmission techniques gives a basis for more detailed studies into the areas of interest. Alternative methods of generating and detecting VSB are covered, offering possible ways of simplifying system implementation. A method of synchronizing VSB is proposed and analysed, giving a simple solution to the synchronization problem. VSB, as a spectrally efficient signalling format, is shown to be suitable for transmission over nonlinear channels; its performance comparing favourably with alternative systems. A new method of attaining spectrally efficient transmission is analysed. This combines VSB and quadrature modulation to obtain a signal with double the spectral efficiency of VSB. With suitable decoding this increased spectral efficiency is obtained at the expense of only a small sacrifice in power efficiency.

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  • Positioning in Media Dialogue: Negotiating Roles in the News Interview by Elda Weizman

    Matheson, D. (2010)

    Journal Articles
    University of Canterbury Library

    This book is a series of analyses of how interviewers and interviewees position themselves and each other in Israeli television news interviews, all based on interviews from the early evening current affairs show, ‘Erev Xadash’ in the early 1990s. There is a lot of convincing, not to mention enjoyable, close analysis of moments of verbal sparring in Israeli televised politics that will add to understanding of the news interview and of institutional talk in general. Weizman brings together insights from across the discourse analytic literature to tease out aspects of the relations between participants and the textual strategies through which those relations are negotiated. The chapters exploring the use of irony and terms of address in what Weizman terms the ‘challenge-saturated environments’ of Israeli news interviews make particularly interesting reading. It is here that the book’s conclusions are concentrated – for example, that interviewees rarely make ironic statements at the expense of the interviewer, and more often at the expense of third parties, while interviewers are more likely to target political figures they are interviewing, but rarely others.

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  • A note on James K. Baxter’s late poem ‘A Pair of Sandals’

    Millar, P.; Sharp, I. (2001)

    Unclassified
    University of Canterbury Library

    In his introduction the editor writes: 'I have also included “A Pair of Sandals” by James K. Baxter. This is a bit cheeky, since “A Pair of Sandals” clearly wasn’t written in 2001. Baxter died in 1972. But the poem was published for the first time in a 2001 selection of Baxter’s work edited by Paul Millar. I wanted to salute the excellent work Millar has done in retrieving Baxter’s more fugitive poems and making them accessible to contemporary readers.'

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  • A Note on the Probability of Winning a Lottery when the Number of Competitors is a Binomial Random Variable

    Hogan, S.; Meriluoto, L. (2010)

    Discussion / Working Papers
    University of Canterbury Library

    RePEc Working Paper: 48/2010

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  • Evaluation of Tangible User Interfaces for Desktop AR

    Dünser, A.; Looser, J.; Grasset, R.; Seichter, H.; Billinghurst, M. (2010)

    Conference Contributions - Published
    University of Canterbury Library

    In this work we evaluated the usability of tangible user interaction for traditional desktop augmented reality environments. More specifically, we compared physical sliders and tracked paddles, and traditional mouse input for a system control task. While task accuracy was the same for all interfaces, mouse input performed the fastest and input with a tracked paddle the slowest. Performance with the physical sliders fell between those two. We present these results along with various findings from user comments, and discuss how they may influence the design of future desktop AR systems.

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  • Does tenure review in New Zealand’s South Island give rise to rents?

    Brower, A.; Meguire, P. (2010)

    Discussion / Working Papers
    University of Canterbury Library

    RePEc Working Paper: No. 49/2010 Supporting paper for poster presented at the 2010 meeting of the New Zealand Association of Economists.

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  • Cliometrics and Time Series Econometrics: Some Theory and Applications

    Greasley, D.; Oxley, L. (2010)

    Discussion / Working Papers
    University of Canterbury Library

    RePEc Working Paper Series: No: 56/2010

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  • To use constructed-response questions, or not to use constructed-response questions? that is the question

    Hickson, S.; Reed, W.R.; Sander, N. (2010)

    Discussion / Working Papers
    University of Canterbury Library

    RePEc Working Paper Series: No. 69/2010

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  • Comment on 'Promises and Partnership'

    Deck, C.; Servatka, M.; Tucker, S. (2011)

    Discussion / Working Papers
    University of Canterbury Library

    RePEc Working Paper Series: No. 14/2011

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  • Analyzing Fixed-event Forecast Revisions

    Franses, P.H.; Chang, C.L.; McAleer, M. (2011)

    Discussion / Working Papers
    University of Canterbury Library

    RePEc Working Paper Series: No. 25/2011

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  • Risk Management of Risk Under the Basel Accord: A Bayesian Approach to Forecasting Value-at-Risk of VIX Futures

    Casarin, R.; Chang, C.L.; Jiménez-Martín, J.; McAleer, M.; Pérez-Amara, T. (2011)

    Discussion / Working Papers
    University of Canterbury Library

    RePEc Working Papers Series: No. 26/2011

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  • GFC-Robust Risk Management Under the Basel Accord Using Extreme Value Methodologies

    Santos, P.S.; Jiménez-Martín, J.; Michael McAleer, M.; Amaral, T. (2011)

    Discussion / Working Papers
    University of Canterbury Library

    RePEc Working Paper Series: No. 28/2011

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  • Teachers’ fleeting encounters in online professional development communities blended with strong school communities of practice

    Mackey, J. (2010)

    Conference Contributions - Other
    University of Canterbury Library

    The intersections between virtual and physical communities provide an important but largely unfamiliar, undefined and overlooked context in which to examine teachers’ professional learning. Recent work in this field, for example Finlay (2008) and Slaouti (2007), signals the need to better understand the ways teachers blend formal online study with the situated learning which occurs within everyday participation in communities of practice. As Laferriere, Lamon and Chan (2006) state “despite much enthusiasm given to the use of technology in education, the potential of e-learning in transforming teacher learning is neither sufficiently explored nor well understood.” Research focusing on the intersections between work and study, and particularly the role of online learning for professional development, represents an area of growing interest. This is true not only in teacher education but in the wider field of professional learning, development and support (Stacey & Gerbic, 2009; Maor & Volet, 2007). This study examines teacher learning supported by elective study in a graduate diploma in information and communication technology programme offered by a New Zealand university. Participants were predominantly studying part-time while working in schools.

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  • Mental health services for older people: a critical appraisal of the literature. New Zealand Health Technology Assessment Report Vol. 7(2)

    Ahuriri-Driscoll, A.; Rasmussen, P.; Day, P (2004)

    Reports
    University of Canterbury Library

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  • Saving irrigation water by accounting for windbreaks

    de Vries, T.T.; Cochrane, T.A.; Galtier, A. (2010)

    Conference Contributions - Published
    University of Canterbury Library

    Water for irrigation in the Canterbury region of New Zealand is becoming an increasingly precious commodity as it is in many other areas of the world. Adequate use of this resource will define the economical and environmental future of the region. Current irrigation systems, even under best management practices, over-apply water, as they do not account for spatial variability of crop water needs in fields. Over-application of water is wasteful and has environmental and economical repercussions. Water requirements are determined by crop evapotranspiration (ET). Key factors affecting ET in Canterbury are wind and solar radiation. Both of these are significantly affected by windbreaks, resulting in variability in ET and water requirements across a field. Understanding the variability in ET caused by windbreaks will enable for the correct application of water through precision irrigation systems. A theoretical model was developed to estimate savings in irrigation by accounting for windbreaks in the Canterbury region. Windbreaks reduce evapotranspiration and therefore crops/pasture behind windbreaks needs less water than those in other parts of the field. Results for a case study in Canterbury show that windbreaks can potentially reduce the annual on-farm water consumption by 10 to 20%, while still maintaining ideal crop/pasture yields. In the short term, the application of precision irrigation systems in fields with windbreaks can have farm level benefits of improved water use and reduced nitrogen/phosphorus leaching. In the long term this could translate directly into cost savings because of a potential decrease in energy used for irrigation (running pumps, etc.).

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  • New Zealand-China Relations: Common Points and Differences

    Brady, A-M. (2008)

    Journal Articles
    University of Canterbury Library

    The 35th anniversary of New Zealand establishing diplomatic relations with the People’s Republic of China (PRC) fell on 22 December 2007. This anniversary was marked by high-powered celebrations in both Beijing and Wellington. Yet, it should not be forgotten that New Zealand-China relations stretch much longer than the 35 years of formal relations with the PRC. There is a saying in Chinese, “when drinking water, think of its source” (yin shui si yuan), and in this paper I will survey some of the historical sources of New Zealand’s current close interest in, and involvement with, China. New Zealand has long had an extensive and complex relationship with China. The diversity of these long-term connections has resulted in an unusually high level of awareness of China and its people in New Zealand, and a strong interest in expanding the relationship still further. Another saying is also useful as a framework for understanding New Zealand-China relations: “seek common points; face up to differences.” China’s rising dominance in the Asia-Pacific region in recent years has brought about a significant readjustment in New Zealand’s foreign policy, one which the New Zealand population appears ill-prepared to adjust to and which poses a number of challenges for the future. In the second half of the paper, I will discuss some of the points New Zealand has in common with China, along with some of the differences.

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