285 results for Conference poster

  • Te Punga and the Net Generation

    Wilkinson, Elizabeth; Sutton, Megan (2006)

    Conference poster
    The University of Auckland Library

    Our existing Voyager catalogue tutorial was text-heavy and decontextualised— detached from student experience, youth culture and the research process. The aim was to create a student-centred tutorial, applying sound learning principles, providing relevant contexts for first year students and using Net Gen modes to convey the information.

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  • Approximated Ground Truth for Stereo and Motion Analysis on Real-World Sequences (Poster)

    Liu, Zhifeng; Klette, Reinhard (2009)

    Conference poster
    The University of Auckland Library

    Conference details: The 3rd Pacific-Rim Symposium on Image and Video Technology (PSIVT2009) Tokyo, Japan, January 13th—16th, 2009 http://psivt2009.nii.ac.jp/ We approximate ground truth for real-world stereo sequences and demonstrate its use for the performance analysis of a few selected stereo matching and optic flow techniques. Basically we assume zero roll and constant tilt of an ego-vehicle (for about 10 seconds) driving on a planar road.

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  • Inclusion of a Second-Order Prior into Semi-Global Matching. (2009)

    Hermann, Simon; Klette, Reinhard; Destenfanis, Eduardo (2009)

    Conference poster
    The University of Auckland Library

    Conference details: The 3rd Pacific-Rim Symposium on Image and Video Technology (PSIVT2009) Tokyo, Japan, January 13th—16th, 2009 http://psivt2009.nii.ac.jp/ We consider different parameter settings for SGM, suggest to include a second order prior into the smoothness term of the energy function, and propose and test a new cost function. Some preprocessing (edge images) proves to be of value for improving SGM stereo results on real-world data.

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  • Recovery Rate of Clustering Algorithms. (2009)

    Li, Fajie; Klette, Reinhard (2009)

    Conference poster
    The University of Auckland Library

    Conference details: The 3rd Pacific-Rim Symposium on Image and Video Technology (PSIVT2009) Tokyo, Japan, January 13th—16th, 2009 http://psivt2009.nii.ac.jp/ We provide a simple and general way for defining the recovery rate of clustering algorithms using a given family of old clusters for evaluating the performance when calculating a family of new clusters. The recovery rate may be calculated by using an approximate and efficient algorithm.

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  • Effects of complex milk lipid components on neurodevelopment in vitro

    Lim, JH; Hodgkinson, S; Dragunow, M; Norris, C; Vickers, M (2010-11)

    Conference poster
    The University of Auckland Library

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  • Afferent axonal pathfinding in developing chicken rhomboencephalon

    Kubke, Maria; Wild, JM (2008)

    Conference poster
    The University of Auckland Library

    The developing hindbrain of vertebrates i organized in a series of rhombomeres, each giving rise to specifi c nuclei. The role of this segmentation has been extensively studied with respect to the origin of motor nuclei. The development of afferent innervation, however, has received little attention. Afferent axons enter the brainstem prior to the migration of their central targets and must therefore navigate in the absence of target derived information. Since the target nuclei for each afferent component originates within discrete rhombomeric boundaries, it is possible that the same positional information that is used by neuronal progenitors to defi ne their fi nal fate, may be available to afferent axons to direct them through their initial growth. This study was aimed at determining the normal sequence that characterises the growth of afferent axons in the hindbrain within the context of the site of origin and of the organisation of second order sensory neurons within specifi c rhombomere boundaries. Afferent axons were labelled at different embryonic ages using fl uorescent lipophilic dyes. Crystals of DiI and/or DiO were placed on specifi c exposed nerves or nerve branches of fi xed embryos. Embryos were incubated at 30 C for 18 hrs, after which the hindbrains were dissected, cleared in glycerol and analysed as whole-mount preparations with confocal microscopy. Afferent axons formed a series of fascicles that extended longitudinally along the alar plate, beyond the rhombomeric boundaries that give rise to their target nuclei. At early stages, the degree of organization and segregation of afferent axons did not appear to refl ect the adult patterns. Thus, it appears that the appropriate pathfi nding and fi nal segregation of the afferent components involves an initial profuse growth into the hindbrain, and that proper afferent patterning involves axon retraction and may require the initiation of migration if the central targets towards their fi nal position.

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  • Bronchoconstriction and the MBNW: Insights from anatomical lung modelling.

    Mitchell, Jennine; Tawahi MH (2010-11-30)

    Conference poster
    The University of Auckland Library

    Bronchoconstriction and the MBNW: Insights from anatomical lung modelling. Jennine Mitchell and Dr Merryn Tawhai Auckland Bioengineering institute The multiple breath nitrogen washout (MBNW) is a global test of lung function that produces two indices Sacin and Scond that are reflective of ventilation heterogeneity arising at the level of acinus and between more spatially disparate regions of the lung respectively. An important application of the MBNW is in the study of asthma. Ventilation defects have been noted to occur in imaging studies of asthma. These regional ventilation defects have not previously been considered in relation to the MBNW indices. Scond is purported to be related to the state of conducting airways however no modelling studies exist which directly link the airway state to Scond. In this work regional ventilation defects have been simulated in an anatomically based human lung model and theoretically linked to the MBNW indices Sacin and Scond. Ventilation is simualted to the level of the acinus in a model in which acinar ventilation is considered independent of ventialtion in other acini. As previously indicated in modelling studies a high degree of constriction is required to produce a ventilation defect. The relationship between the degree of constriction in airways leading to the defect and the Scond index is however highly non-linear and shows a sharp decrease at very high levels of constriction. Ventilation defects potentially cause non-communication of gas trapped in the ventilation defects with the mouth. This may alter the calculation of FRC if nitrogen dilution is used to calculate FRC. As the indices are dependent on the phase III slope for each breath being normalised by FRC this alters MBNW results. The index Scond is not be able to be explained simply in terms of increased time constants due to increased resistance in the main conducting airway tree. The model indicates that the Scond index is more complex than current MBNW theory indicates and cannot be simply explained in terms of a longer time constant due to constriction in the conducting airway tree resulting in increased late emptying of poorly ventilated regions.

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  • Using stream biofilm microbial communities as indicators of freshwater ecosystem health

    Lewis, Gillian; Ancion, PY; Lear, G; Roberts, K; Washington, V (2010-08-23)

    Conference poster
    The University of Auckland Library

    Stream biofilms are a complex aggregation of microorganisms embedded in a polymer matrix and cover almost every surface in freshwater environments. Because of their sedentary way of life, microorganisms associated with biofilms are affected by past and present environmental conditions and therefore constitute a potential integrative indicator of stream health. A wide range of experiments was conducted in both flow chamber microcosms and natural stream environments to investigate the main drivers of microbial community structure and composition and evaluate the potential use of biofilms as a bio-indicator of freshwater ecosystem health. Using community fingerprinting techniques such as terminal-Restriction Fragment Length Polymorphism and Automated Ribosomal Intergenic Spacer Analysis as well as 16S rRNA gene clone libraries we investigated variations occurring in biofilm bacterial and ciliate protozoan communities. Initial experiments conducted in flow chamber microcosms showed that significant differences in microbial community structure could be detected within only a few days of exposure to common water contaminants and remained detectable weeks after transfer to uncontaminated water. Further research investigating biofilm of more than 60 stream sites variously impacted by urbanization revealed a strong separation between rural and urban streams and confirmed the potential use of stream biofilm as a bio-indicator of stream health. Environmental monitoring techniques developed in this project were then successfully tested to investigate the efficacy of an enclosed stormwater treatment system, where traditional biological indicators such as macro-benthic invertebrates were not available. We are now extending our research to 300 different streams in order to define a general Bacterial Community Index characterising stream ecosystem health based on the structure of biofilm bacterial communities.

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  • A Variant of Adaptive Mean Shift-Based Clustering

    Li, Fajie; Klette, Reinhard (2008)

    Conference poster
    The University of Auckland Library

    Conference Details: ICONIP 2008 - 15th International Conference on Neural Information. Processing of the Asia-Pacific Neural Network Assembly November 25-28, 2008, Auckland, New Zealand We are interested in clustering sets of highly overlapping clusters. For example, given is an observed set of stars (considered to be a set of points); how to find (recover) clusters which are the contributing galaxies of the observed union of those clusters? Below we propose a modification of an adaptive mean shift-based clustering algorithm (called Algorithm 1) proposed in 2003 by B. Geogescu, I. Shimsoni and P. Meer

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  • Impact of PCV7 on antibiotic susceptibiity of nasophayngeal Streptococcus pneumoniae in South Auckland children

    Sekikawa, E; Trenholme, A; Taylor, S; Lennon, Diana; McBride, C; Best, Emma (2011-03-17)

    Conference poster
    The University of Auckland Library

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  • Cell proliferative and radioprotective properties of bioactive Salvia sclareoides extracts

    Ruivo, D; Oliveira, Maria; Rauter, AP; Justino, J; Goulart, M (2008-11)

    Conference poster
    The University of Auckland Library

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  • Cardiac response to weak electrical shocks challenges the functional syncytium paradigm

    Caldwell, Bryan; Trew, Mark; Pertsov, AM (2015-04-11)

    Conference poster
    The University of Auckland Library

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  • Institutional Collaboration around Institutional Repositories

    Hayes, Leonie; Stevenson, Alison; Mason, Ingrid; Scott, Anne; Kennedy, Peter (2007)

    Conference poster
    The University of Auckland Library

    Three New Zealand universities have been collaborating on a project to provide open, web-based, access to research outputs through the creation of institutional repositories using the DSpace software. This poster will therefore address the theme of eResearch with particular focus on the benefits of active collaboration, intra-university, inter-university and international, in this area of activity. New Zealand has a small population of 4 million, an innovative and resourceful academic community, a newly implemented research funding model, based on performance (PBRF) and a readiness to stay competitive with the rest of the world. Institutional Repositories in New Zealand are in their infancy but a considerable body of experience already exists overseas which we can draw upon if we work in partnership with those institutions who have already implemented institutional repositories. Funding is limited but by sharing resources and working collaboratively each institution can make substantial progress towards the creation of individual repositories. This poster reports on the joint project between the University of Auckland, the University of Canterbury and Victoria University of Wellington. The three partners have been funded by the New Zealand Tertiary Education Commission to make available, via the Internet for access by Open Archives Initiative (OAI) compliant search engines, research outputs created by staff and students of the three partner institutions. This poster will present information on the work to: • Establish DSpace repositories in partner institutions that conform to the OAI-PMH standard. • Contribute to the development of linkages with the Australian DEST funded information infrastructure projects, i.e. ADT, APSR and ARROW projects. • Identify methods for increasing academic understanding of, and promoting contributions to, digital repositories the content of which is then available to enhance teaching and learning, as well as research. • Provide digital materials, either through the deposit of “born digital” material or through digitisation of material already available in print, that contribute to the developing digital content landscape as envisaged in the NZ Digital Strategy • Contribute to national research resource discovery service to be established by the National Library of New Zealand. Ensure that the content in the project repositories is visible for harvesting by global OAI-compliant search engines such as Google Scholar, OAIster, etc. Collaborate with other IR projects and communicate the lessons learned to the wider tertiary and research communities of New Zealand

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  • CellML: Cellml.org, Tools and Community

    Lawson J.; Lloyd C.; Noble P.; Hunter P.; Nielsen P. (2007)

    Conference poster
    The University of Auckland Library

    Poster presented at ICSB2007 The purpose of CellML is to store and exchange computer-based mathematical models of as wide a range of scale and subject as posssible. For example, biochemical signalling and metabolic systems can be embedded in electrophysiological models of excitable cells in CellML. The CellML language is an open standard based on the XML markup language and is being developed by the Bioengineering Institute at the University of Auckland and affiliated research groups [1]. The majority of computational biology publications aim to discuss their model but often fail to provide a comprehensive set of instructions for recreating the model, or include errors preventing reproduction of published model outputs. Publishing a paper with a link to a CellML model facilitates the wide distribution and recreation of that model, and additionally forces the modeller to carefully consider matters such as unit consistency. The CellML specification and application programming interfaces (API) are driven by a core team, but a growing international community is involved in work related to CellML. A community website (www.cellml.org) has been set up as a focal point for the community and also functions as a model repository. A number of groups are developing software tools for CellML and using the language for research in computational biology. A repository of almost 300 unique CellML models is available at www.cellml.org/models: these are computational models from peer-reviewed publications that have been coded into CellML. These models are undergoing an active curation process based on the MIRIAM standard, proposed by the international biological modelling community [2]. This process includes provision of comprehensive documentation, annotation with citation and model author metadata, maintenance of file modification histories, and correspondence with model authors to ensure that models define all required initial conditions and parameters. The CellML community strongly supports collaboration with other groups to continue to set standards for curation and distribution of biological models. A number of free / open source software tools for developing and simulating CellML models are available, including Physiome CellML Environment (PCEnv) and Cellular Open Resource (COR). Other modelling environments such as JSim and Virtual Cell also support the CellML format. Information on further tools such as validators, debuggers and simulation specific packages can be found at www.cellml.org/tools. In the near future, models in the cellml.org model repository will be completely annotated with ontologies such as BioPaX and references to databases such as UniProt. Models will be broken down into the components from which they are comprised, and these components will themselves be curated, providing a toolbox of standardised computational parts from which new models can be created, in an in silico analogy to the MIT Registry of Standard Biological parts (http://parts.mit.edu/registry/index.php/Main_Page). An API has recently been developed for software tools to allow interaction between CellML and SVG diagrams of models, such as biochemical pathway schematics, and work is also underway to standardise graphical representations of CellML models. For more information, please join the CellML community mailing list at http://www.cellml.org/mailman/listinfo/cellml-discussion. 1.) Cuellar, A.A., Lloyd, C. M., Nielsen, P. F., Bullivant, D. P., Nickerson, D. P., Hunter, P. J. "An Overview of CellML 1.1, a Biological Model Description Language" Simulation, 2003, 79, No. 12, 740-747 2.) Le Novere, N., Finney, A., Hucka, M., Bhalla, U.S., Campagne, F., Collado-Vides, J., Crampin, E.J., Halstead, M., Klipp, E., Mendes, P., Nielsen, P., Sauro, H., Shapiro, B., Snoep, J.L., Spence, H.D., Wanner, B.L. "Minium information requested in the annotation of biochemical models (MIRIAM)" Nature Biotechnology, 2005, 23 1509-1515

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  • Mechanisms Of Differences In Ventilation Distribution In The Upright, Supine, And Prone Postures

    Tawhai, Merryn; Hedges, Kerry (2011-05-13)

    Conference poster
    The University of Auckland Library

    Rationale: Measurements of ventilation distribution using various imaging modalities have suggested that the distribution of ventilation in the supine and prone postures is less evidently gravitational than when the lung is upright, and with some studies showing little difference between ventilation distributions in the prone and supine lung. This is despite the concurrent observations of a significant gradient in tissue density when supine, and a typically smaller - or absent - tissue density gradient prone. In this study we use a computational model of lung tissue elasticity coupled to air-flow to study the relationship between posture, density distribution, and ventilation. Methods: An imaging-based geometric model of the lung and airway tree that was developed in a separate study was used here. Flow in the airways was simulated using a one-dimensional fluid dynamics model that includes flow-dependent airway resistance and coupling to tissue elasticity at the airway walls and at the acini. A finite deformation elasticity model was used to predict the effect of gravity on tissue deformation, and the non-linear elasticity of each acinar tissue unit during simulated breathing. The upright lung volume was defined from pulmonary function testing; the supine and prone volumes were assumed to be the same, and equal to the supine air volume as calculated from the subject's computed tomography imaging acquired at FRC. Tissue density and ventilation at each of the ~32,000 distributed acini in the model were averaged within iso-gravitational slices of 10 mm thickness. Results: The gradient of tissue density predicted by the model was markedly larger in supine than in upright or prone. Ratios of the maximum to minimum slice density were 1.95, 1.51, and 1.39 for supine, prone, and upright, respectively. Ventilation in the upright model increased on average towards the dependent tissue, whereas ventilation in supine and prone was decreased in the most dependent and non-dependent regions. The ratios of maximum to minimum slice ventilation were 1.09, 1.03, and 1.31 for supine, prone, and upright, respectively. Conclusions: A lack of gravitational distribution of ventilation in the supine and prone postures compared with upright is predicted on the basis of the smaller size of the horizontal lung and a shift of the dependent tissue to a less-compliant region of the sigmoidal pressure-volume curve at its lower asymptote. This is the same mechanism that results in early filling of the non-dependent tissue when inhaling from residual volume.

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  • The use of whole community bacterial indicators to monitor ecological health, function and variability within stream biofilms

    Lear, Gavin; Boothroyd, IK; Lewis, Gillian (2009-08-30)

    Conference poster
    The University of Auckland Library

    This study describes the extent of variability in biofilm bacterial community structure across a broad range of spatial and temporal scales and assesses whether this may be used as an indicator of stream ecological health and function. A community DNA fingerprinting technique (Automated Ribosomal Intergenic Spacer Analysis - ARISA) was used to examine the structure of bacterial communities within freshwater stream biofilms. When compared with macrobenthic invertebrate community assemblages using multi-dimensional scaling techniques, similar broad-scale trends in population structure were revealed between organisms at these different trophic levels. For both communities, spatial variability in community structure was greater between streams than within each site, or compared to temporal variability measured over 1 year. Distance-based redundancy analysis of both bacterial ARISA and macroinvertebrate data estimated that the largest cause of variation in community structure was due to differences in catchment land-use, rather than any single water quality parameter (e.g. ph or ammoniacal nitrogen). Multidimensional scaling of ARISA data also revealed significant differences in community structure between urban, and less impacted stream sites, providing evidence that whole-bacterial communities could be used as an indicator of freshwater ecological health, analogous to the way that macroinvertebrate communities have been used for many years. In conclusion, we propose the analysis of whole bacterial communities as a cost-effective, high throughput alternative indicator of freshwater ecological health.

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  • Human Adenovirus ecology in environmental waters in New Zealand

    Dong, Yimin; Lewis, Gillian (2008-08-17)

    Conference poster
    The University of Auckland Library

    A major New Zealand study of pathogen occurrence in surface freshwaters identified occurrence of human adenovirus in 30% of sites and samples by qualitative PCR based methods. The source or nature of these viruses was not clear from the study and raises important questions in both viral ecology and human health protection. The aim of this study was to begin to unravel these questions by (i) development of specific quantitative analysis methods for adenoviruses in water and (ii) to target identifiable groups of adenovirus associated with human respiratory or gastrointestinal infections. These quantitative group specific real time PCR methods were tested in drinking water, recreational water, river water and wastewater. Adenovirus was detected in all primary wastewater samples tested (n=10) at high genome copy number (1.87 x104 to 4.6 x106 per litre) and in 33% (n=15) of the river water and 11% (n=27) of the treated drinking water samples. In addition, adenovirus was detected in 5 of the 6 estuarine recreational water samples (17 to 1190 virus genome copies per litre). DNA sequence analysis suggested that human adenovirus group C (respiratory infection associated) were most commonly associated with river, recreational and drinking water. Group F adenovirus (gastroenteritis associated viruses) were found to dominate in most wastewater (5 - 100 % total adenovirus) but were not detected in surface waters. This study suggests that the ecology of specific groups or types of adenovirus is sufficiently different, external to the host, to have important implications for human health risk assessment.

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  • Delayed Cerebral Post-arteriole Dilation is Consistent with Observations at Multiple Spatial and Temporal Scales: Evidence from Mathematical Modelling

    Barrett, MJP; Tawhai, MH; Suresh, Vinod (2011-05-25)

    Conference poster
    The University of Auckland Library

    Background and aims: Observations from different neurovascular imaging modalities provide conflicting evidence about the presence and/or extent of volume changes in post-arteriole blood vessels. At the level of individual vessels, two-photon imaging during functional activation shows a rapid increase in arteriolar diameter, but little or no increase in capillaries or venules 1 . In contrast, 'bulk' measurements of flow-volume relationships show large increases in arterial volume 2 , and smaller - but still significant - increases in venous volume 3 . Here, we reconcile these competing observations using a dynamic, biophysically based mathematical model of the hemodynamic response. Methods: We use the widely known Windkessel model that represents blood flow as analogous to electrical current, and networks of blood vessels as analogous to electrical resistances and capacitances. The model also includes a novel description of vascular compliance, viscoelastic effects, and stimulus-driven vasodilation. Experimental observations at progressively more detailed scales are used to constrain and validate the model, following a 'top down' approach. In addition, we test the assumption that post-arteriole vessels do not dilate, and use the model to predict observations at progressively more aggregated scales, following a 'bottom up' approach. Results: Model predictions of the total, arterial, and venous steady state flow-volume relationships agree well with experimental observations, as do predictions of transient changes in flow and volume during functional activation. The model also predicts rapid arteriole dilation during activation. Interestingly, this is accompanied by slow increases in capillary and venule diameter that - for brief stimulation - are near indistinguishable from baseline noise. When assuming no dilation of capillaries or venules, there are only minor differences between the model predictions at the single vessel scale. However, predictions at more aggregated scales are qualitatively and quantitatively different from experimental observations. Conclusions: The model presented here is able to reproduce the main features of experimental observations over a range of spatial and temporal scales. These results suggest that arterial dilation represents the majority of regional cerebral blood volume increases during functional activation, especially during brief stimulation. However, passive dilation in capillaries and venules may be increasingly significant during extended stimulation. This is an important consideration when interpreting or comparing results from neurovascular imaging modalities, such as optical methods and magnetic resonance imaging.

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  • Effect of light regimes on the utilisation of an exogenous carbon source by freshwater biofilm communities

    Lear, Gavin; Lewis, Gillian (2007-06-23)

    Conference poster
    The University of Auckland Library

    Biofilms are a major source of ‘in stream’ primary production, exhibiting high population density, and being an important source of carbon for microbial heterotrophs. Changing patterns of land-use within freshwater catchment areas may greatly impact on stream biofilm microbial community structure, which in turn may influence the speed and extent with which full ecosystem recovery may occur. This study reports how freshwater biofilm communities respond to additions of acetate, used as a proxy for organic matter, the primary source of carbon within shaded forests and headwater streams. The use of [ 13C] acetate and subsequent isolation of 13C-labelled nucleic acids from the metabolically active fraction of the bacterial community enabled substrate assimilating organisms to be identified. In addition, biofilms were exposed to varied levels of incident light to assess the relative contribution of phototrophic and heterotrophic nutrition.

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  • Ecosystem responses to multiple-stressor gradients: Nutrient and sediment addition to experimental stream channels

    Wagenhoff, A; Matthaei, CD; Lear, Gavin; Lewis, Gillian; Townsend, CR (2009-05-16)

    Conference poster
    The University of Auckland Library

    Agricultural land use can strongly affect stream ecosystems by increasing levels of nutrients and fine sediment cover on the streambed. Knowledge of patterns in ecological responses along gradients of these two stressors will help define thresholds of harm. Leaf breakdown rates, algal and bacterial communities are directly and/or indirectly influenced by nutrient supply and fine sediment cover. To investigate the effects of stressor gradients and their interactions on these biological response parameters, we designed a full-factorial experiment in circular stream-side channels with eight levels each of nutrients (36 to 6900 μg·l-1 DIN, 1.4 to 450 μg·l-1 DRP) and fine sediment (0 to 100 % cover). Algal biomass, bacterial diversity and leaf pack decomposition were determined after three weeks of exposure to both stressors. Algal biomass was significantly higher in channels with lower levels of fine sediment. Bacterial diversity generally increased with increasing nutrient concentrations up to an intermediate nutrient level but then decreased again with the exception of reaching the highest diversity overall at the top nutrient level. Thus, increased levels of nutrients and fine sediment caused major changes to the algal and bacterial communities. In turn, these changes affect other food-web components as well as ecosystem functioning, including decomposition.

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