5,605 results for 2013

  • Synthesis and in vitro and in vivo evaluation of antimalarial polyamines

    Liew, Lydia; Pearce, Allison; Kaiser, M; Copp, Brent (2013-11)

    Journal article
    The University of Auckland Library

    We recently reported that 1,14-diphenylacetamide derivatives of spermine exhibit potent nM in vitro growth inhibition properties of Plasmodium falciparum. In an effort to expand the structure-activity relationship of this compound class towards malaria, we have prepared and biologically tested a library that includes benzamide and 3-phenylpropanamide 'capping acid' groups, and polyamines that include spermine (PA3-4-3) and chain extended analogues PA3-8-3 and PA3-12-3. 2-Hydroxy and 2,5-dimethoxy analogues were typically found to exhibit the most potent activity towards the dual drug resistant strain K1 of P. falciparum with IC50's in the range of 1.3-9.5 nM, and selectivity indices (SI) of 42,300 to 4880. In vivo evaluation of three analogues against Plasmodium berghei was undertaken, with one demonstrating a modest 27.9% reduction in parasitaemia.

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  • The unfulfilled pedagogical promise of the dialogic in writing: Intertextual writing instruction for diverse settings

    Jesson, Rebecca; Parr, Judith; McNaughton, Stuart (2013)

    Book item
    The University of Auckland Library

    In this chapter, the authors use writing as a site to consider the intersection between culture and effective pedagogy. They identify the general principles surrounding pedagogy, which is considered to be culturally responsive, and then examine the research to consider these principles specifically with regard to the teaching of writing in linguistically and culturally diverse contexts. The chapter explores ways to incorporate deliberately the general principles of culturally responsive pedagogy in the teaching of writing. It also offers a view of writing and writing instruction as dialogic, with the aim of incorporating students' existing knowledge and practices. By considering students' intertextual histories as a key resource for writing, the chapter considers that there is potential to develop instruction that is contingent upon and responsive to students' various experiences with texts.

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  • Effects of supercritical carbon dioxide processing on optical crystallinity and in vitro release of progesterone and Gelucire 44/14 solid and semi-solid dispersions

    Falconer, James; Wen, Jingyuan; Zargar-Shoshtari, S; Chen, John; Farid, Mohammed; Young, S; Alany, Raid (2013)

    Journal article
    The University of Auckland Library

    The aim of this study was to determine the effect of supercritical carbon dioxide (SC-CO2) on the crystallinity and drug release of Gelucire 44/14-based endogenous progesterone (PGN) dispersion systems. The light scattering from PGN crystals incorporated in Gelucire 44/14 was imaged using optical microscopy. In vitro dissolution was used to determine the release kinetics of PGN, Gelucire 44/14, incorporated by a supercritical fluid (SCF) method. Release profiles were evaluated according to zero-order, first-order, Higuchi, Krosmeyer-Peppas, and dual first-order models. The dual first-order release model illustrated two distinct release rates: an initial rapid release followed by a slow diffusion of PGN from the dispersion systems. The dual first-order release model adds a new tool to the elucidation of release mechanisms from lipid and micelle-forming-based dispersion systems, where parallel processes contribute to drug release.

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  • Classroom assessment in writing

    Parr, Judith (2013)

    Book item
    The University of Auckland Library

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  • Evaluation as a double-edged sword: Building schools??? evaluative capability while evaluating their efforts in raising achievement

    Parr, Judith; Timperley, Helen (2013)

    Book item
    The University of Auckland Library

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  • High purity distillation column: Simulation and optimization

    Udugama, IA; Kirkpatrick, Robert; Yu, Wei; Young, Brent (2013)

    Conference item
    The University of Auckland Library

    Distillation columns with a high-purity product (down to 7 ppm) have been studied. A steady state model is developed using a commercial process simulator. The model is validated against industrial data. Based on the model, three major optimal operational changes are identified. These are, lowering the location of the feed and side draw streams, increasing the pressure at the top of the distillation column and changing the configuration of the products draw. It is estimated that these three changes will increase the throughput of each column by 5%. The validated model is also used to quantify the effects on key internal column parameters such as the flooding factor, in the event of significant changes to product purity and throughput.

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  • Reduced crowding and poor contour detection in schizophrenia are consistent with weak surround inhibition

    Robol, V; Tibber, MS; Anderson, EJ; Bobin, T; Carlin, P; Shergill, SS; Dakin, Steven (2013-04-09)

    Journal article
    The University of Auckland Library

    Background Detection of visual contours (strings of small oriented elements) is markedly poor in schizophrenia. This has previously been attributed to an inability to group local information across space into a global percept. Here, we show that this failure actually originates from a combination of poor encoding of local orientation and abnormal processing of visual context. Methods We measured the ability of observers with schizophrenia to localise contours embedded in backgrounds of differently oriented elements (either randomly oriented, near-parallel or near-perpendicular to the contour). In addition, we measured patients??? ability to process local orientation information (i.e., report the orientation of an individual element) for both isolated and crowded elements (i.e., presented with nearby distractors). Results While patients are poor at detecting contours amongst randomly oriented elements, they are proportionally less disrupted (compared to unaffected controls) when contour and surrounding elements have similar orientations (near-parallel condition). In addition, patients are poor at reporting the orientation of an individual element but, again, are less prone to interference from nearby distractors, a phenomenon known as visual crowding. Conclusions We suggest that patients??? poor performance at contour perception arises not as a consequence of an ???integration deficit??? but from a combination of reduced sensitivity to local orientation and abnormalities in contextual processing. We propose that this is a consequence of abnormal gain control, a phenomenon that has been implicated in orientation-selectivity as well as surround suppression.

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  • Orientation-crowding within contours

    Glen, JC; Dakin, Steven (2013-07)

    Journal article
    The University of Auckland Library

    We examined how crowding (the breakdown of object recognition in the periphery caused by interference from "clutter") depends on the global arrangement of target and distracting flanker elements. Specifically we probed orientation discrimination using a near-vertical target Gabor flanked by two vertical distractor Gabors (one above and one below the target). By applying variable (opposite-sign) horizontal offsets to the positions of the two flankers we arranged the elements so that on some trials they formed contours with the target and on others they did not. While the presence of flankers generally elevated orientation discrimination thresholds for the target we observe maximal crowding not when flanker and targets were co-aligned but when a small spatial offset was applied to flanker location, so that contours formed between flanker and targets only when the target orientation was cued. We also report that observers' orientation judgments are biased, with target orientation appearing either attracted or repulsed by the global/contour orientation. A second experiment reveals that the sign of this effect is dependent both on observer and on eccentricity. In general, the magnitude of repulsion is reduced with eccentricity but whether this becomes attraction (of element orientation to contour orientation) is dependent on observer.We note however that across observers and eccentricities, the magnitude of repulsion correlates positively with the amount of release from crowding observed with co-aligned targets and flankers, supporting the notion of fluctuating bias as the basis for elevated crowding within contours.

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  • A template for change? De-risking the transition to CDIO

    Robinson, K; Friedrich, Heide; Kirkpatrick, Robert; Nicholas, C; Rowe, G (2013)

    Journal article
    The University of Auckland Library

    This paper provides a case study on how an established, mature engineering faculty, with a large population of students can make the successful, high risk, step change transition towards the delivery of CDIO objectives: ???Graduating engineers who can conceive-design-implement-operate complex value-added engineering systems in a modern team-based environment??? (Crawley et al, 2011). The successful results of the project demonstrated the effectiveness of the systems thinking and CDIO approach, and endorsed this as the basis for a major change strategy. Not only did it demonstrate the quality of all the students on the course, their potential and commitment to engineering, but it also demonstrated willingness of the faculty to take a risk and to embrace change. The project scenario opened up an otherwise overlooked teaching resource: that of practitioner lecturers with many years of experience of implementation and operation of major projects. These skills were essential to the scoping, design, planning and implementation of the project as well as giving the backdrop of best practice from industry. Auckland???s experience of introducing a major step change may be used as a template for other universities who may wish to follow Auckland???s example. This project shows the value of a hearts and minds approach to change as it brought together students, staff and best practice under a multidisciplinary systems thinking and CDIO approach; all united in the interests of reconstructing Christchurch.

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  • Scheduling tree-shaped task graphs to minimize memory and makespan

    Marchal, L; Sinnen, Oliver; Vivien, F (2013)

    Conference item
    The University of Auckland Library

    This paper investigates the execution of tree-shaped task graphs using multiple processors. Each edge of such a tree represents a large IO file. A task can only be executed if all input and output files fit into memory, and a file can only be removed from memory after it has been consumed. Such trees arise, for instance, in the multifrontal method of sparse matrix factorization. The maximum amount of memory needed depends on the execution order of the tasks. With one processor the objective of the tree traversal is to minimize the required memory. This problem was well studied and optimal polynomial algorithms were proposed. Here, we extend the problem by considering multiple processors, which is of obvious interest in the application area of matrix factorization. With the multiple processors comes the additional objective to minimize the time needed to traverse the tree, i.e., to minimize the make span. Not surprisingly, this problem proves to be much harder than the sequential one. We study the computational complexity of this problem and provide an inapproximability result even for unit weight trees. Several heuristics are proposed, each with a different optimization focus, and they are analyzed in an extensive experimental evaluation using realistic trees.

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  • Happiness, subjective well-being and quality of life

    Medvedev, Oleg; Landhuis, E (2013-06-08)

    Conference item
    The University of Auckland Library

    Existing definitions of happiness, subjective well-being, and quality of life suggest conceptual overlap between these constructs. The current paper addresses the call for empirical data initiated by Camfield & Skevington (2008) in order to verify these relationships. In the study 180 university students completed the Oxford Happiness Questionnaire, the World Health Organisation Quality of Life Questionnaire, the Satisfaction with Life and the Positive and Negative Affect Scales. The results show that all well-being measures have high loadings on the single well-being factor that explains 83% of variance in both the Oxford Happiness Questionnaire and the psychological domain of Quality of Life. Strong correlations were found between happiness, psychological and health domains of quality of life, life satisfaction, and positive affect. Together these data suggest a general well-being factor that can be measured using different approaches and support interchangeable use of terms happiness, subjective well-being and psychological well-being.

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  • Flexible hierarchy ray tracing on FPGAs

    Collinson, S; Sinnen, Oliver (2013)

    Conference item
    The University of Auckland Library

    Rendering programs use ray tracing to artificially create photo-realistic scenes that would otherwise be too dangerous, too costly or physically impossible to fabricate. Acceleration of the rendering process can be achieved through spatial or object hierarchy structures, which aim to restrict the number of expensive ray-object intersection calculations along a ray path by trading them for traversal of the structure. With extensive inherent parallelism, ray tracing benefits from GPU acceleration but may also benefit from the more flexible control flow and memory architecture available with FPGAs. We present a flexible FPGA based ray tracing platform capable of traversing varying widths and types of acceleration hierarchies to evaluate their efficiency. The platform consists of four main controllers for communication, traversal, intersection and memory. The platform interfaces with LuxRays, an open-source C++ renderer, over PCIexpress to transfer data for computation to onboard memory. We implement a configuration of the platform at 250MHz on our target device that shows promising results compared to CPU and GPU renders.

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  • Pyjama: OpenMP-like implementation for Java, with GUI extensions

    Vikas; Giacaman, Nasser; Sinnen, Oliver (2013)

    Conference item
    The University of Auckland Library

    Incremental parallelism is an uncomplicated and expressive parallelisation practice and has led to wide adoption of OpenMP. However, the OpenMP specification does not present a binding for the Java language and the OpenMP threading model finds limited use for GUI (Graphical User Interface) application development. Our research strives towards supporting OpenMP-like directives to simplify parallelism for Java and address the limitations of the OpenMP model in the development of interactive applications. We present a compiler-runtime system for OpenMP-like directives in Java, enhanced with GUI-aware mechanisms. This paper describes the compiler and the runtime. We introduce GUI-aware directives and propose methods for incremental concurrency. We present and discuss the performance of programs written using our system by comparing them with previous attempts and traditional ways of parallelisation, using the parallel Java Grande Forum (JGF) benchmarks and a fractal-generation application with a GUI.

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  • Hardware acceleration of biomedical models with OpenCMISS and CellML

    Yu, Ting; Bradley, Christopher; Sinnen, Oliver (2013)

    Conference item
    The University of Auckland Library

    OpenCMISS is a mathematical modeling environment designed to solve field based equations and link subcellular and tissue-level biophysical processes to organ-level processes. It employs a general purpose parallel design, in particular distributed memory, for its computations. CellML is a mark up language based on XML that is designed to encode lumped parameter biophysically based systems of ordinary differential equations and nonlinear algebraic equations. OpenCMISS allows CellML models to be evaluated and integrated into models at various spatial and temporal scales. With good inherent parallelism, hardware acceleration based on FPGAs has a great potential to increase the computational performance and to reduce the energy consumption of computations with CellML models integrated in OpenCMISS. However, with several hundred CellML models, manual hardware implementation for each CellML model is complex and time consuming. The advantages of FPGA designs will only be realised if there is a general solution or a tool to automatically convert CellML models into hardware description languages such as VHDL. In this paper we describe the architecture for the FPGA hardware implementation of CellML models and evaluate the first results related to performance and resource usage based on a variety of criteria.

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  • Using OpenMP under Android

    Vikas, ST; Giacaman, Nasser; Sinnen, Oliver (2013)

    Conference item
    The University of Auckland Library

    The majority of software authored for the mobile platforms are GUI-based applications. With the advent of multi-core processors for the mobile platforms, these interactive applications need to employ sophisticated programming constructs for parallelism-concurrency, in order to leverage the potential of these platforms. An OpenMP-like, easy to use programming construct, can be an ideal way to add productivity. However, such as environment needs to be adapted to object-oriented needs and should be designed with an awareness of the interactive applications. Also, OpenMP does not provide a binding that target these platforms. This paper presents a compiler-runtime system for Android that presents OpenMP-like directives and GUI-aware enhancements.

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  • The outlook for control of New Zealand???s most abundant, widespread and damaging invertebrate pests: Social wasps

    Lester, PJ; Beggs, Jacqueline; Brown, BL; Edwards, ED; Gorenteman, R; Toft, RJ; Twidle, A; Ward, Darren (2013)

    Journal article
    The University of Auckland Library

    Invasive social wasps (Vespula germanica and V. vulgaris) are probably the most damaging, widespread invertebrate pests in New Zealand. In large areas of beech forests they can attain a biomass as great as, or greater than, the combined biomasses of birds, rodents and stoats. Wasps are effective and voracious predators and pose a significant risk to human health. Here, we highlight the scale and diversity of wasp impacts and the opportunities to develop cost effective landscape-scale tools for wasp control. Toxic baits can be extremely effective for wasp control, though the most effective pesticide (fipronil) is currently not commercially available for wasp control within New Zealand. Significant progress has been made to enhance lures for toxin delivery, including the use of synthetic lures. Biological control could offer the possibility of controlling wasps over huge areas at reasonable cost, though previous releases of biocontrol agents have not been successful. Avenues for further biological control work, such as the use of pathogens or parasitoids, are encouraged. We believe it is necessary and strategic to develop a suite of control tools. We urge government and the public to take action to control the wasp problem and to designate one agency as having the prime responsibility for doing this. Given that wasps are harming our natural heritage and inhibiting or adversely affecting people???s enjoyment of natural areas, we look to the natural resource sector to drive research and implement solutions. This includes Department of Conservation, Ministry of Primary Industry and Councils.

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  • Welded indicatives: The spatial constructions of John Panting

    Smith, John (2013)

    Journal article
    The University of Auckland Library

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  • A new investigative approach to understanding heat migration pathways within the shallow subsurface at Orakei Korako, New Zealand

    Lynne, Bridget; Smith, GJ (2013)

    Conference item
    The University of Auckland Library

    A heat flow survey of Orakei Korako, located within the Taupo Volcanic Zone, New Zealand was undertaken in 2012 using the new multi-technique approach of sinter analyses, infrared imaging, downhole temperature measurements, Ground Penetrating Radar and surface heat loss calculations. The survey established sites of elevated temperature, not only at the surface but also in the shallow subsurface ( < 5 m depth). Sinter mineralogy and morphology identified acidic steam condensate, post-depositional overprinting at sites of elevated temperature in the subsurface, and unaltered sinter at the surface even though there were elevated subsurface temperatures. Ground Penetrating Radar (GPR) imaged strong amplitude reflections over unaltered sinter deposits and weak amplitude reflections where the sinter had been altered via acidic steam condensate. GPR also imaged subsurface conduits for ascending steam, which were confirmed by measured downhole temperatures of > 90??C. Infrared imaging of individual sites within the geothermal field and heat loss calculations of accessible hot springs and pools provided further information on the heat flow at Orakei Korako. This new multi-method approach identified areas of heat in the subsurface where there is no present-day evidence of heat at the surface, and areas of sustained heat in the subsurface as evidenced by the high level of acidic steam condensate overprinting of surface sinter deposits. Repeated surveys will identify if the surface and shallow subsurface heat flow mapped in 2012 shifts around Orakei Korako, and map areas of the field that are heating up or cooling down with time.

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  • Examination of core from drillhole OKM3 on the western bank of Orakei Korako geothermal field

    Purnomo, MJ; Lynne, Bridget; Zarrouk, Sadiq; Boseley, C (2013)

    Conference item
    The University of Auckland Library

    The present-day surface activity at Orakei Korako dominantly occurs on the eastern side of the Lake Ohakuri with only minor surface activity on the western bank. A 30m deep drill hole (OKM3) was drilled on the western bank to monitor the shallow groundwater level. Continuous core was recovered providing the first core from the western side of Lake Ohakuri, as previously reported cored drillholes are located on the eastern side of Lake Ohakuri. Examination of OKM3 core involved identifying the lithology and stratigraphy which consists of pyroclastic rocks of Taupo Pumice alluvium and Akatarewa breccias. At 22 m depth a thin (~10 cm) siliceous sinter horizon is present, indicating historic surface discharge of alkali chloride thermal water. X-Ray Diffraction (XRD), petrographic microscopy, Scanning Electron Microscopy (SEM) and Energy-Dispersive X-Ray Spectroscopy (EDS) were used to examine hydrothermal alteration within the core. Hydrothermal alteration minerals identified include zeolites (mordenite and clinoptilolite). These zeolites are common alteration products of pyroclastic rocks and infer low temperature alteration (~220??C) alteration, was identified at 27-28 m depth. The location of the drill site is on an uplifted block of the Emerald fault and this relict alteration indicates temperatures >220 ??C where at depth at some stage in the past. These findings reveal low temperature hydrothermal alteration has taken place in the shallow environment (<30 m depth) on the western side of Lake Ohakuri. However, historically, high temperature geothermal fluid occurred at depth in this area. Presently, no thermal activity occurs at the surface. The identification of relict high temperature zone and a previously unknown siliceous sinter horizon at 22 m depth indicates historic flow of alkali chloride fluids at surface and high temperature fluid at depth was more widespread than that of today.

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  • Numerical Evaluation of Forces on Piled Bridge Foundations in Laterally Spreading Soil

    McGann CR (2013)

    Theses / Dissertations
    University of Canterbury Library

    The response of piled bridge foundations to liquefaction-induced lateral soil deformation is an important design consideration in seismically active regions. Recent research and case history data suggest that three-dimensional deformation of the approach embankment can significantly influence the loads placed on the embedded foundations during a flow failure or lateral spreading event. For example, the 2010 Maule earthquake in Chile caused widespread lateral spreading in the soil surrounding the Mataquito river bridge, however, only insignificant structural damage was observed in the bridge itself. The discrepancy between the amount of soil deformation and structural damage suggests that design procedures for this load case that do not make adequate consideration for 3D soil deformation mechanisms may lead to overly conservative and expensive design solutions. Finite element models of the Mataquito river bridge are created using the OpenSees computational framework to investigate the reduction in foundation loads during lateral spreading implied by the minimal structural damage at the site. These models include beam on nonlinear Winkler foundation models, dynamic effective stress models of the bridge-foundation-soil system in plane strain, and 3D models of the southern bridge abutment, approach embankment, and surrounding soil. This numerical work focuses on the development of efficient element formulations and appropriate mesh configurations to minimize computational effort, and seeks to frame the load reduction mechanisms in the context of a simplified analysis procedure for the lateral spreading load case. The results of the numerical models for the Mataquito bridge, along with a parameter study conducted using a second set of 3D finite element models, indicate that consideration for the 3D geometry of the bridge site results in tangible reductions in foundation bending demands and abutment displacements compared to those returned by a plane strain description of the problem. This reduction increases as the depth of the liquefiable layer and the effective width of the approach embankment are decreased. An approach is proposed to estimate the reductions in abutment displacement and associated foundation bending demands for a given site geometry, and an existing simplified analysis procedure is modified to better consider the findings of this work.

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