89,483 results

  • Development of a possibilistic method for the evaluation of predictive uncertainty in rainfall-runoff modeling

    Jacquin, AP; Shamseldin, Asaad (2007)

    Journal article
    The University of Auckland Library

    [1] Using a possibilistic approach, this study develops a methodology for the evaluation of predictive uncertainty in rainfall-runoff modeling. The methodology proposed herein can be regarded as a further extension of the well-known generalized likelihood uncertainty estimation (GLUE) methodology. Both methods are based on the equifinality paradigm, under which it is accepted that there may be many model structures and parameter sets (within a given model structure) that are compatible with the knowledge available about the real system. In both methodologies, uncertainty bounds of the model predictions are obtained using Monte Carlo simulations. The essential difference between them is that while in the GLUE methodology the likelihood weights of behavioral simulations are used to obtain prediction quantiles, in the possibilistic methodology the possibility distributions of the model outputs are used to derive the prediction uncertainty bounds. The methodology presented in this study is applied to a conceptual type rainfall-runoff model. Copyright 2007 by the American Geophysical Union.

    View record details
  • The antiresorptive effects of a single dose of zoledronate persist for two years: a randomized, placebo-controlled trial in osteopenic postmenopausal women.

    Grey, Andrew; Bolland, Mark; Wattie, D; Horne, Anne; Gamble, Gregory; Reid, Ian (2009)

    Journal article
    The University of Auckland Library

    Context: Annual iv administration of 5 mg zoledronate decreases fracture risk. The optimal dosing interval of 5 mg zoledronate is not known. Objective: Our objective was to determine the duration of antiresorptive action of a single 5-mg dose of iv zoledronate. Design, Setting, and Participants: We conducted a double-blind, randomized, placebo-controlled trial over 2 yr at an academic research center, in a volunteer sample of 50 postmenopausal women with osteopenia. Intervention: Intervention included 5 mg zoledronate. Main Outcome Measures: Biochemical markers of bone turnover and bone mineral density of the lumbar spine, proximal femur, and total body. Results: Compared with placebo, zoledronate treatment decreased mean levels of each of four markers of bone turnover by at least 38% (range 38???45%) for the duration of the study (P < 0.0001 for each marker). After 2 yr, bone mineral density was higher in the zoledronate group than the placebo group by an average of 5.7% (95% confidence interval = 4.0???7.4) at the lumbar spine, 3.9% (2.2???5.7) at the proximal femur, and 1.7% (0.8???2.5) at the total body (P < 0.0001 for each skeletal site). Between-groups differences in markers of bone turnover and bone mineral density were similar at 12 and 24 months. Mild secondary hyperparathyroidism was present throughout the study in the zoledronate group. Conclusion: The antiresorptive effects of a single 5-mg dose of zoledronate are sustained for at least 2 yr. The magnitudes of the effects on markers of bone turnover and bone mineral density are comparable at 12 and 24 months. Administration of zoledronate at intervals of up to 2 yr may be associated with antifracture efficacy; clinical trials to investigate this possibility are justified.

    View record details
  • Colour mimicry and sexual deception by Tongue orchids (Cryptostylis)

    Gaskett, Anne; Herberstein, ME (2010)

    Journal article
    The University of Auckland Library

    Typically, floral colour attracts pollinators by advertising rewards such as nectar, but how does colour function when pollinators are deceived, unrewarded, and may even suffer fitness costs? Sexually deceptive orchids are pollinated only by male insects fooled into mating with orchid flowers and inadvertently transferring orchid pollinia. Over long distances, sexually deceptive orchids lure pollinators with counterfeit insect sex pheromones, but close-range deception with colour mimicry is a tantalising possibility. Here, for the first time, we analyse the colours of four sexually deceptive Cryptostylis orchid species and the female wasp they mimic (Lissopimpla excelsa, Ichneumonidae), from the perspective of the orchids??? single, shared pollinator, male Lissopimpla excelsa. Despite appearing different to humans, the colours of the orchids and female wasps were effectively identical when mapped into a hymenopteran hexagonal colour space. The orchids and wasps reflected predominantly red-orange wavelengths, but UV was also reflected by raised bumps on two orchid species and by female wasp wings. The orchids??? bright yellow pollinia contrasted significantly with their overall red colour. Orchid deception may therefore involve accurate and species-specific mimicry of wavelengths reflected by female wasps, and potentially, exploitation of insects??? innate attraction to UV and yellow wavelengths. In general, mimicry may be facilitated by exploiting visual vulnerabilities and evolve more readily at the peripheries of sensory perception. Many sexually deceptive orchids are predominantly red, green or white: colours that are all potentially difficult for hymenoptera to detect or distinguish from the background.

    View record details
  • Orchid pollination by sexual deception: pollinator perspectives

    Gaskett, Anne (2011)

    Journal article
    The University of Auckland Library

    The extraordinary taxonomic and morphological diversity of orchids is accompanied by a remarkable range of pollinators and pollination systems. Sexually deceptive orchids are adapted to attract specific male insects that are fooled into attempting to mate with orchid flowers and inadvertently acting as pollinators. This review summarises current knowledge, explores new hypotheses in the literature, and introduces some new approaches to understanding sexual deception from the perspective of the duped pollinator. Four main topics are addressed: (1) global patterns in sexual deception, (2) pollinator identities, mating systems and behaviours, (3) pollinator perception of orchid deceptive signals, and (4) the evolutionary implications of pollinator responses to orchid deception, including potential costs imposed on pollinators by orchids. A global list of known and putative sexually deceptive orchids and their pollinators is provided and methods for incorporating pollinator perspectives into sexual deception research are provided and reviewed. At present, almost all known sexually deceptive orchid taxa are from Australia or Europe. A few sexually deceptive species and genera are reported for New Zealand and South Africa. In Central and Southern America, Asia, and the Pacific many more species are likely to be identified in the future. Despite the great diversity of sexually deceptive orchid genera in Australia, pollination rates reported in the literature are similar between Australian and European species. The typical pollinator of a sexually deceptive orchid is a male insect of a species that is polygynous, monandrous, haplodiploid, and solitary rather than social. Insect behaviours involved in the pollination of sexually deceptive orchids include pre-copulatory gripping of flowers, brief entrapment, mating, and very rarely, ejaculation. Pollinator behaviour varies within and among pollinator species. Deception involving orchid mimicry of insect scent signals is becoming well understood for some species, but visual and tactile signals such as colour, shape, and texture remain neglected. Experimental manipulations that test for function, multi-signal interactions, and pollinator perception of these signals are required. Furthermore, other forms of deception such as exploitation of pollinator sensory biases or mating preferences merit more comprehensive investigation. Application of molecular techniques adapted from model plants and animals is likely to deliver new insights into orchid signalling, and pollinator perception and behaviour. There is little current evidence that sexual deception drives any species-level selection on pollinators. Pollinators do learn to avoid deceptive orchids and their locations, but this is not necessarily a response specific to orchids. Even in systems where evidence suggests that orchids do interfere with pollinator mating opportunities, considerable further research is required to determine whether this is sufficient to impose selection on pollinators or generate antagonistic coevolution or an arms race between orchids and their pollinators. Botanists, taxonomists and chemical ecologists have made remarkable progress in the study of deceptive orchid pollination. Further complementary investigations from entomology and behavioural ecology perspectives should prove fascinating and engender a more complete understanding of the evolution and maintenance of such enigmatic plant-animal interactions.

    View record details
  • Orchid sexual deceit provokes ejaculation

    Gaskett, Anne; Winnick, CG; Herberstein, ME (2008-06)

    Journal article
    The University of Auckland Library

    Sexually deceptive orchids lure pollinators by mimicking female insects. Male insects fooled into gripping or copulating with orchids unwittingly transfer the pollinia. The effect of deception on pollinators has been considered negligible, but we show that pollinators may suffer considerable costs. Insects pollinating Australian tongue orchids (Cryptostylis species) frequently ejaculate and waste copious sperm. The costs of sperm wastage could select for pollinator avoidance of orchids, thereby driving and maintaining sexual deception via antagonistic coevolution or an arms race between pollinator learning and escalating orchid mimicry. However, we also show that orchid species provoking such extreme pollinator behavior have the highest pollination success. How can deception persist, given the costs to pollinators? Sexually???deceptive???orchid pollinators are almost exclusively solitary and haplodiploid species. Therefore, female insects deprived of matings by orchid deception could still produce male offspring, which may even enhance orchid pollination.

    View record details
  • Flood estimation at ungauged sites using artificial neural networks

    Dawson, CW; Abrahart, RJ; Shamseldin, Asaad; Wilby, RL (2006)

    Journal article
    The University of Auckland Library

    Artificial neural networks (ANNs) have been applied within the field of hydrological modelling for over a decade but relatively little attention has been paid to the use of these tools for flood estimation in ungauged catchments. This paper uses data from the Centre for Ecology and Hydrology's Flood Estimation Handbook (FEH) to predict T-year flood events and the index flood (the median of the annual maximum series) for 850 catchments across the UK. When compared with multiple regression models, ANNs provide improved flood estimates that can be used by engineers and hydrologists. Comparisons are also made with the empirical model presented in the FEH and a preliminary study is made of the spatial distribution of ANN residuals, highlighting the influence that geographical factors have on model performance. ?? 2005 Elsevier Ltd All rights reserved.

    View record details
  • Beyond Risk Factors: Towards a Holistic Prevention Paradigm for Children and Young People

    France, AP; Homel, R; Freiberg, K (2010)

    Journal article
    The University of Auckland Library

    Since the mid 1990s early intervention and prevention has become a central feature of public policy across the western world. This development has had a major impact on reconstructing the prevention paradigm in children and youth services. It has been underpinned by the emergence of the science of risk factor analysis (RFA). This paradigm has had mixed success in prevention work but has gained significant political credence and support. While RFA has reshaped prevention approaches it does have methodological and practice limitations. This paper argues for a more holistic approach to prevention policy and social work practice, one that recognises risk but does not allow it to dominate. We explore the growing body of evidence for RFA, outlining both its strengths and weaknesses and show how a more holistic approach can be adopted. We argue that the fundamental focus for analysis and intervention needs to recognise the social and cultural context of developmental pathways, and emphasises needs to be on relations between levels of organisation in a child’s or young person’s developmental process . We draw on the Australian Pathways to Prevention Programme to illustrate how social work can and should be developed to create more holistic approaches to prevention

    View record details
  • Statistical Downscaling of Watershed Precipitation using Gene Expression Programming (GEP)

    Hashmi, MZ; Shamseldin, Asaad; Melville, Bruce (2011)

    Journal article
    The University of Auckland Library

    Investigation of hydrological impacts of climate change at the regional scale requires the use of a downscaling technique. Significant progress has already been made in the development of new statistical downscaling techniques. Statistical downscaling techniques involve the development of relationships between the large scale climatic parameters and local variables. When the local parameter is precipitation, these relationships are often very complex and may not be handled efficiently using linear regression. For this reason, a number of non-linear regression techniques and the use of Artificial Neural Networks (ANNs) was introduced. But due to the complexity and issues related to finding a global solution using ANN-based techniques, the Genetic Programming (GP) based techniques have surfaced as a potential better alternative. Compared to ANNs, GP based techniques can provide simpler and more efficient solutions but they have been rarely used for precipitation downscaling. This paper presents the results of statistical downscaling of precipitation data from the Clutha Watershed in New Zealand using a non-linear regression model developed by the authors using Gene Expression Programming (GEP), a variant of GP. The results show that GEP-based downscaling models can offer very simple and efficient solutions in the case of precipitation downscaling.

    View record details
  • Development of rainfall???runoff models using Takagi???Sugeno fuzzy inference systems

    Jacquin, AP; Shamseldin, Asaad (2006)

    Journal article
    The University of Auckland Library

    This study explores the application of Takagi???Sugeno fuzzy inference systems to rainfall???runoff modelling. The models developed intend to describe the non-linear relationship between rainfall as input and runoff as output to the real system using a system based approach. Two types of fuzzy models are proposed, where the first type is intended to account for the effect of changes in catchment wetness in the rainfall???runoff transformation and the second type incorporates seasonality as a source of non-linearity in this relationship. The models developed are applied to data from six catchments of diverse climatic characteristics. The results of the fuzzy models are compared with those of the Simple Linear Model, the Linear Perturbation Model and the Nearest Neighbour Linear Perturbation Model, which use similar input information. The results of this study indicate that fuzzy inference systems are a suitable alternative to the traditional methods for modelling the non-linear relationship between rainfall and runoff.

    View record details
  • Societal access routes and developmental pathways: putting social structure and young people's voice into the analysis of pathways into and out of crime

    France, Alan; homel, R (2006)

    Journal article
    The University of Auckland Library

    Central to pathways research is the analysis of the social processes involved in human action and the influences that have shaping qualities. At the heart of these social processes are human beings who exercise agency and help construct themselves and their environments. Shaping influences include changing social structures; political ideologies and policy innovations; and changes taking place in the cultural sphere of social life. In studying the actions of individuals within changing social environments it is important to make a distinction between individual developmental pathways and societal access routes. Access routes appear in different forms to different people in terms of accessibility and attractiveness. Understanding this perceptual dimension requires listening to the voices of children and young people.This is illustrated by reference to the work of the United Kingdom (UK) Economic & Social Research Council (ESRC) research network, Pathways Into and Out of Crime, which shows how culture, structure and policy influence young people???s everyday lives and decisions. It also shows that what young people really value is not programs but a supportive relationship with a nonjudgmental adult who is able to help them negotiate their way through difficult circumstances. The focus of prevention efforts should be on changing social arrangements to create opportunities and systems that facilitate the formation of such supportive structures. The

    View record details
  • Risk factor analysis and the youth question

    France, Alan (2008)

    Journal article
    The University of Auckland Library

    This paper is concerned with exploring how in late modernity the 'youth question' is being addressed by public policy and what impact this is having on understandings of childhood and youth. Historically the youth question has been shaped by adult anxieties over youth delinquency and their problems of social integration. In late modernity, this is still the case but new approaches to tackling social problems are emerging. Public policy influenced by the emerging 'science of prevention' has developed new forms of interventions, which are seen in the expansion of risk factor analysis in prevention policy. This paper explores the development of this new approach to the youth question, highlighting its history, its influence and its underlying assumptions. The concluding discussion will show how this area of public policy development is leading to greater levels of regulation and intervention and is widening the net in terms of defining young people as the future problem generation.

    View record details
  • The use of Th1 cytokines, IL-12 and IL-23, to modulate the immune response raised to a DNA vaccine delivered by gene gun.

    Williman, Jonathan; Slobbe, L; Buchan, G; Baird, MA (2006)

    Journal article
    The University of Auckland Library

    Unlike intramuscular injection, gene gun delivery of DNA drives a strong type 2 response. In an effort to counter this, we have genetically fused the type 1 cytokines, IL-12 and IL-23, to the hemagglutinin (HA) gene from influenza APR/8/34, and delivered these DNA constructs to Balb/c mice. Gene gun delivery of the HA gene was able to induce antibody production by all vaccinated mice. Linking of IL-12 caused almost complete suppression of immune responses whereas mice vaccinated with IL-23HA showed long-lived IgG1 antibody levels. Splenocytes from IL-23HA vaccinated mice also tended to produce more IL-5 and IFN?? after restimulation in vitro than splenocytes from HA vaccinated mice. While codelivery of IL-23 did not change the type of immune response it may increase its longevity following vaccination.

    View record details
  • DNA fusion vaccines incorporating IL-23 or RANTES for use in immunization against influenza.

    Williman, Jonathan; Young, SL; Buchan, G; Slobbe, L; Wilson, M; Pang, P; Austyn, J; Preston, S; Baird, MA (2008)

    Journal article
    The University of Auckland Library

    The incorporation of RANTES or IL-23 into DNA vaccines may improve their immunogenicity by the recruitment and activation of dendritic cells. This may also select for a TH1 response counteracting the TH2 response which can predominate when a DNA vaccine is delivered by gene gun. We have immunized mice with various DNA constructs encoding APR/8/34 influenza virus hemagglutinin (HA), either fused to or separate from, IL-23 or RANTES using a gene gun. Those immunized with IL-23/HA fusion constructs and challenged with influenza 27 weeks post-vaccination, tended to have cleared more virus than those vaccinated with HA DNA. Mice immunized with the RANTES/HA fusion construct produced a mixed TH1/TH2 response whereas in HA-vaccinated mice, a TH2 response predominated. Immunization with a plasmid in which HA and RANTES were under the control of separate promoters, failed to generate a mixed TH1/TH2 response suggesting that enhanced antigen uptake via RANTES receptors may contribute to the mixed immune response generated to the fusion construct. Overall these findings provide further evidence that Type 1 cytokines or chemokines, fused to antigen in a DNA vaccine, can influence the nature and the longevity of the immune response and ultimately, its protective capacity.

    View record details
  • Environmental factors in the development of chronic inflammation: A case-control study on risk factors for Crohn's disease within New Zealand

    Han, DY; Fraser, Alan; Dryland, P; Ferguson, Lynnette (2010)

    Journal article
    The University of Auckland Library

    The role of environmental factors in the risk for Crohn's disease (CD), an inflammatory bowel disease (IBD), was investigated in a North Island-based New Zealand case-control cohort. A total of 315 CD patients and 536 controls were recruited through various sources to the Auckland CD Risk Factor Study. As well as demographic characteristics, the self-reported questionnaire included (1) smoking and drinking alcohol, (2) breastfeeding in infancy, (3) early life exposures to allergens and microbes, (4) health conditions lasting 6 months or longer and (5) taking antibiotics and any medications. There was strong evidence for familial associations of the disease, and minor effects of birth order and number of siblings. Being a smoker, especially over a long time period, and exposure to smoking during childhood and adolescence periods increased risk, whereas drinking alcohol at least once per week showed a slight protective effect. Long term use of the oral contraceptive pill increased the risk of developing CD, but breastfeeding and immunisation during infancy showed no significant association. Long term and debilitating illness (lasting 6 months or more), taking antibiotics prior to developing CD, or taking four or more antibiotics or any regular medication in a year during adolescence substantially increased the CD risk. Having a pet during childhood was a protective factor, but regularly feeding an animal was not sufficient to protect. Many of these significant factors are likely to impact on the colonic microflora and/or immune system. We conclude that, in addition to strong evidence for genetic associations, factors likely to impact on immune response or reduce early exposure to microbes provide a main risk factor for CD in this New Zealand population.

    View record details
  • Study protocol for a non-inferiority trial of cytisine versus nicotine replacement therapy in people motivated to stop smoking

    Greenaway, Natalie; Howe, C; Bullen, Christopher; McRobbie, H; Glover, Marewa; Parag, Varsha; Williman, Jonathan; Veale, R; Nosa, Vili; Barnes, Joanne (2011-11-21)

    Journal article
    The University of Auckland Library

    Background Smokers need effective support to maximise the chances of successful quit attempts. Current smoking cessation medications, such as nicotine replacement therapy (NRT), bupropion, nortriptyline or varenicline, have been shown to be effective in clinical trials but are underused by smokers attempting to quit due to adverse effects, contraindications, low acceptability and/or high cost. Cytisine is a low-cost, plant-based alkaloid that has been sold as a smoking cessation aid in Eastern Europe for 50 years. A systematic review of trial evidence suggests that cytisine has a positive impact on both short- and long-term abstinence rates compared to placebo. However, the quality of the evidence is poor and insufficient for licensing purposes in many Western countries. A large, well-conducted placebo-controlled trial (n = 740) of cytisine for smoking cessation has recently been published and confirms the findings of earlier studies, with 12-month continuous abstinence rates of 8.4% in the cytisine group compared to 2.4% in the placebo group (Relative risk = 3.4, 95% confidence intervals 1.7-7.1). No research has yet been undertaken to determine the effectiveness of cytisine relative to that of NRT.

    View record details
  • Alison Shepherd (Nee Sleigh), ARIBA: 'Success of New Zealand Lady Student' Revisited

    Gatley, Julia (2007)

    Journal article
    The University of Auckland Library

    New Zealand women architects have been the subject of comparatively little scholarly reflection to date. This paper makes a contribution to this field by examining the life and career of Alison Shepherd (1898-1972), who grew up in Christchurch, became one of the Architectural Association's "pioneer women students" in the 1920s and is believed to have been the first New Zealand woman to attain RIBA membership. Following her 1928 marriage to fellow AA graduate J. C. (Jock) Shepherd (1896-1979), Alison spent her adult life in Britain. She maintained a career through marriage, motherhood, the Great Depression and the second world war, retiring in 1957. Career highlights include her contribution to the design of the Shakespeare Memorial Theatre at Stratford-upon-Avon (1927-32) and the publication of more than 30 of her line drawings in one of John Summerson's best-known books, Georgian London (1945). More than simply documenting Alison Shepherd's life and work, this paper attempts to assess the impact her gender might have had on her career; to consider the relationships she might have shared with other expatriate New Zealand architects in Britain in the mid-twentieth century; and to locate her career within the broader context of burgeoning British modernism.

    View record details
  • New media practices in India: bridging past and future, markets and development

    Schwittay, Anke (2011)

    Journal article
    The University of Auckland Library

    This article provides a review of the academic and popular literature on new media practices in India, focusing on the country’s youth's use of mobile phones and the Internet, as well as new media prosumption. One particular feature of the Indian case is the confluence of commercial exploitation of new media technologies and their application for development purposes in initiatives that aim to bring these technologies to marginalized segments of the Indian population. Technology usage in turn is shaped by the socioeconomic location of the user, especially in regards to gender and caste. The potential of new media technologies to subvert such social stratifications and associated norms has inspired much public debate, which is often carried out on the Internet, giving rise to an online public sphere. In all of the writings reviewed here, the tension surrounding new media technologies as a meeting place of the old and the new in India is paramount.

    View record details
  • A living lab: corporate delivery of ICTs in rural India

    Schwittay, Anke (2008)

    Journal article
    The University of Auckland Library

    Information and Ccommunication technologies (ICTs) are increasingly seen as essential tools in development projects that can create new sources of income, make governments more transparent and accessible, improve education and health care, and overcome social exclusion and discrimination. To harness these potentials, multinational hi-tech corporations are forming public–private partnerships with governments, development institutions and civil society organisations in the delivery of ICTs to the rural masses. This article analyses the work of the Hewlett-Packard Corporation (HP), in India, where its three-year i-community programme aimed to bring access to ICTs and resulting benefi ts to rural citizens of Andhra Pradesh. I will show that ICTs are not neutral tools of development as conceptualised by practitioners of ICTD, but are commodities produced by corporations with the ultimate aim to increase the corporate bottom line. They are imbued with relations of power that skew ‘partnerships’ and must fulfi l corporate objectives that weaken their potential impact.

    View record details
  • The Financial Inclusion Assemblage: Subjects, Technics, Rationalities

    Schwittay, Anke (2011)

    Journal article
    The University of Auckland Library

    This article introduces financial inclusion as a global assemblage of subjects, technics, and rationalities that aim to develop poor-appropriate financial products and services. Microfinance forms the foundation, but also the boundary of the assemblage, which is premised on the assumption that the 2.7 billion poor people in the world who do not currently have access to formal loan, savings, and insurance products are in need of such offerings. The work of the Institute for Money, Technology and Financial Inclusion at the University of California, Irvine, with its emphasis on ethnographic research into culturally grounded monetary practices and logics, is presented as an alternative to the quantitative, economic, and financial logics that drive the assemblage.

    View record details
  • Thermal limits of portunid crab heart mitochondria: Could more thermo-stable mitochondria advantage invasive species?

    Iftikar, FI; MacDonald, J; Hickey, Anthony (2010)

    Journal article
    The University of Auckland Library

    The distributions of the native crab Ovalipes catharus and the invasive species Charybdis japonica within New Zealand shores may be defined by thermal tolerance. Doppler ultrasound showed that with increasing temperature O. catharus and C. japonica raised their heart rates (p ??? 0.05). However, C. japonica showed greater plasticity in heart beat duration, or contraction rate with increasing temperature, while O. catharus was more inclined to increase heart rate, and already had a shorter more rapid contraction at 19 ??C. Saponin permeabilized heart fibres enabled tests of mitochondrial function in situ and showed that Leak-I respirational flux was highest for O. catharus at all temperatures. C. japonica showed a greater inner mitochondrial membrane integrity which suggests tighter coupling of oxidative phosphorylation. Although Complex I lost function on exposure to 30 ??C in both species, this occurred more rapidly in O. catharus. Complex II function remains stable at high temperature in both species. O. catharus had higher cytochrome c oxidase (CCO) flux at all temperatures compared to C. japonica indicating elevated concentrations of CCO in O. catharus. The scope to increase CCO flux was greater in the more stenothermal O. catharus than in C. japonica. Overall, this study shows substantial differences in heart function and mitochondria between crab species and provides evidence that mitochondrial integrity may limit species survival and potentially future distributions.

    View record details