96,019 results

  • An Exact Method for Computing the Frustration Index in Signed Networks Using Binary Programming

    Arefkashfi, Seyedsamin; Mason, Andrew; Wilson, Mark (2016-11-28)

    Report
    The University of Auckland Library

    Computing the frustration index of a signed graph is a key to solving problems in different fields of research including social networks, physics, material science, and biology. In social networks the frustration index determines network distance from a state of structural balance. Although the definition of frustration index goes back to 1960, an exact algorithmic computation method has not yet been proposed. The main reason seems to be the complexity of computing the frustration index which is closely related to well-known NP-hard problems such as MAXCUT. New quadratic and linear binary programming models are developed to compute the frustration index exactly. Using the Gurobi solver, we evaluate the frustration index on real-world and synthetic datasets. The synthetic data involves Erd??s-R??nyi networks, Barab??si-Albert networks, and specially structured random graphs. We also use well-known datasets from the sociology literature, such as signed networks inferred from students' choice and rejection as well as datasets from the biology literature including gene regulatory networks. We also provide some results on the frustration index of a political network of countries over time. The results show that exact values of the frustration index can be efficiently computed using our suggested optimisation models. We find that most real-world social networks and some biological networks exhibit a relatively low level of frustration which indicates that they are close to balanced.

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  • An 18,000 year-long eruptive record from Volc??n Chait??n, northwestern Patagonia: Paleoenvironmental and hazard-assessment implications

    Alloway, Brent; Pearce, NJG; Moreno, PI; Villarosa, G; Jara, I; De Pol-Holz, R; Outes, V (2017-07-15)

    Journal article
    The University of Auckland Library

    The 2008 eruption of Volc??n Chait??n (VCha) in northwestern Patagonia was the first explosive rhyolitic eruption to have occurred within a century and provided an unprecedented scientific opportunity to examine all facets of the eruption ranging from magma rheology/ascent rates to ash-fall effects on biota and infrastructure. Up to very recently it was thought that the latest eruption prior to the 2008 event occurred c. 9750 cal. a BP. Although a number of researchers have recognised additional eruptive products, but their stratigraphy, age, and geochemical attributes have not been systematically described and/or recorded. In this study, we provide a detailed examination of andic cover-beds and tephra-bearing lake sequences located both proximally and distally to VCha, which record a series of hitherto unknown rhyolitic eruptive products and place all previous observations firmly within a coherent stratigraphic framework. Through major- and trace-element glass shard geochemistry we are able to confidently verify eruptive source. A total of 20 discrete tephra beds are recognised, with at least 10 having widespread areal distributions and/or depositional imprints broadly comparable to, or greater than, the 2008-tephra event. This record indicates that VCha has been continuously but intermittently active as far back as the end of the Last Glacial Maximum (c. 18,000 cal a BP) with two dominant, genetically related magma types and an intermediary ???mixed??? type. Before this the eruptive record has been largely obscured and/or erased by widespread Andean piedmont glaciation. However, based on the tempo of VCha activity over the last c. 18,000 years, older VCha eruptives can be anticipated to occur as well as future hazardous explosive events. The new eruptive inventory will ultimately be useful for correlating equivalent-aged sequences and refining long-term eruptive tempo as well as corresponding temporal changes in magmatic evolution.

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  • Tsunami runup and tide-gauge observations from the 14 November 2016 M7.8 Kaik??ura earthquake, New Zealand

    Power, W; Clark, K; King, DN; Borrero, J; Howarth, J; Lane, EM; Goring, D; Goff, J; Chagu??-Goff, C; Williams, J; Reid, C; Whittaker, Colin; Mueller, C; Williams, S; Hughes, MW; Hoyle, J; Bind, J; Strong, D; Litchfield, N; Benson, A (2017-07)

    Journal article
    The University of Auckland Library

    The 2016 Mw 7.8 Kaik??ura earthquake was one of the largest earthquakes in New Zealand???s historical record, and it generated the most significant local source tsunami to affect New Zealand since 1947. There are many unusual features of this earthquake from a tsunami perspective: the epicentre was well inland of the coast, multiple faults were involved in the rupture, and the greatest tsunami damage to residential property was far from the source. In this paper, we summarise the tectonic setting and the historical and geological evidence for past tsunamis on this coast, then present tsunami tide gauge and runup field observations of the tsunami that followed the Kaik??ura earthquake. For the size of the tsunami, as inferred from the measured heights, the impact of this event was relatively modest, and we discuss the reasons for this which include: the state of the tide at the time of the earthquake, the degree of co-seismic uplift, and the nature of the coastal environment in the tsunami source region.

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  • Effect of panretinal photocoagulation on corneal sensation and the corneal subbasal nerve plexus in diabetes mellitus

    Misra, Stuti; Ahn, HN; Craig, Jennifer; Pradhan, M; Patel, Dipika; McGhee, Charles (2013-07-02)

    Journal article
    The University of Auckland Library

    PURPOSE: To assess the effects of panretinal photocoagulation (PRP) for diabetic retinopathy (DR) on the human corneal subbasal nerve plexus (SBNP) and to investigate correlations between corneal subbasal nerve (SBN) density, corneal sensitivity, and diabetic peripheral neuropathy. METHODS: Thirty-eight subjects with at least a 10-year history of diabetes mellitus (DM) or DR were included. Subjects were assigned to a PRP group (n = 19), having undergone a treatment of retinopathy in at least one eye or a non-PRP group (n = 19), with no history of PRP. The Michigan Neuropathy Screening Instrument (MNSI) was administered to enable quantification of neuropathic symptoms. Laser scanning in vivo confocal microscopy was performed to capture images of the corneal SBNP to allow determination of SBNP density. Central corneal sensitivity (CST) was evaluated by noncontact aesthesiometry and peripheral vibration perception threshold was measured with a biothesiometer. RESULTS: Mean SBNP densities were 12.27 ?? 4.28 mm/mm??) in the PRP group and 12.75 ?? 3.59 mm/mm?? in the non-PRP group. There were no significant differences in SBNP density (P = 0.71), CST (P = 0.84), MNSI score (P = 0.19), and biothesiometry (P = 0.77) between the PRP and non-PRP groups. When data from both groups (n = 38) were combined, corneal sensitivity was modestly correlated with SBNP density (r = 0.30, P = 0.06), and peripheral biothesiometry (r = 0.26, P = 0.11). CONCLUSIONS: In DM correlation of corneal sensitivity, SBNP density, and peripheral biothesiometry may have a potential role in estimating the severity of peripheral neuropathy. Corneal SBNP density and sensitivity appear to be unaffected by PRP laser treatment compared with non-PRP diabetic eyes.

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  • Interocular Comparison by In Vivo Confocal Microscopy of the 2-Dimensional Architecture of the Normal Human Corneal Subbasal Nerve Plexus

    Misra, Stuti; Craig, Jennifer; McGhee, Charles; Patel, Dipika (2012-12)

    Journal article
    The University of Auckland Library

    PURPOSE: To investigate the configuration of the living human corneal subbasal nerve plexus in paired eyes of normal subjects using in vivo confocal microscopy. METHODS: Laser scanning in vivo confocal microscopy was performed on both corneas of healthy human subjects, and a grid fixation pattern facilitated examination of consistent areas of central to midperipheral cornea. Macromedia/Adobe Freehand 10 was used to manually arrange images into contiguous montages. The subbasal nerve density and overall patterns were analyzed. RESULTS: Both eyes of 6 subjects (3 women and 3 men, aged between 25 and 36 years) were examined. In all subjects, the subbasal nerve plexus exhibited a clockwise whorl configuration inferior to the central cornea. The mean subbasal nerve density at the whorl was 39.17 ?? 4.95 mm/mm and 41.36 ?? 4.19 mm/mm in the right and left eyes, respectively. There was no significant difference in the nerve density between the eyes (P = 0.61). Bland and Altman analysis confirmed high intraobserver repeatability and moderate interobserver repeatability. CONCLUSIONS: This study reveals the marked similarities between the corneal subbasal nerve plexus configuration in the right and left eyes of the living human cornea, highlighting that the typical mirror-image symmetry in corneal topographic patterns is not obeyed in respect to corneal innervation and that a clockwise orientation of the subbasal plexus is typically encountered. There was no statistical difference in the subbasal nerve density between the eyes.

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  • Stratigraphy, age and correlation of middle Pleistocene silicic tephras in the Auckland region, New Zealand: A prolific distal record of Taupo Volcanic Zone volcanism

    Alloway, Brent; Westgate, J; Pillans, B; Pearce, N; Newnham, R; Byrami, M; Aarburg, S (2004)

    Journal article
    The University of Auckland Library

    Coastal sections in the Auckland region reveal highly carbonaceous and/or highly weathered clay???dominated cover???bed successions with numerous discrete distal volcanic ash (tephra) layers, fluvially reworked siliciclastic (tephric) deposits, and two widely distributed pyroclastic density current (PDC) deposits generated from explosive silicic volcanism within the Taupo Volcanic Zone (TVZ). The younger of the two PDC deposits (informally named Waiuku tephra) is glass???isothermal plateau fission???track (ITPFT) dated at 1.00 ?? 0.03 Ma and occurs in a normal polarity interval interpreted as the Jaramillo Subchron. Waiuku tephra is correlated with Unit E sourced from the Mangakino Volcanic Centre of the TVZ. Waiuku tephra can be subdivided into two distinctive units enabling unequivocal field correlation: a lower stratified unit (dominantly pyroclastic surge with fall component) and an upper massive to weakly stratified unit (pyroclastic flow). At many sites in south Auckland, Waiuku tephra retains basal ???surge???like??? beds (<1.4 m thickness). This provides clear evidence for primary emplacement and is an exceptional feature considering the c. 200 km this PDC has travelled from its TVZ source area. However, at many other Auckland sites, Waiuku tephra displays transitional sedimentary characteristics indicating lateral transformation from hot, gas???supported flow/surge into water???supported mass flow and hyperconcentrated flow (HCF) deposits. The older PDC deposit is dated at 1.21 ?? 0.09 Ma, is enveloped by tephras that are ITPFT???dated at 1.14 ?? 0.06 Ma (above) and 1.21 ?? 0.06 Ma (below), respectively, and occurs below a short normal polarity interval (Cobb Mountain Subchron) at c. 1.19 Ma. This PDC deposit, correlated with Ongatiti Ignimbrite sourced from the Mangakino Volcanic Centre of TVZ, has laterally transformed from a gas???supported, fine???grained pyroclastic flow deposit at Oruarangi, Port Waikato, into a water???supported volcaniclastic mass flow deposit farther north at Glenbrook Beach. The occurrence of Ongatiti Ignimbrite in Auckland significantly extends its northward distribution. Large numbers of post??? and pre???Ongatiti rhyolitic tephra layers, ranging in age from c. 1.31 to 0.53 Ma, are also recognised in the region, with some up to 0.5 m in compacted fallout thickness. Although some tephras can be attributed to known TVZ eruptions (e.g., Ahuroa/Unit D), many have yet to be identified in proximal source areas and remain uncorrelated. However, some can be reliably correlated to tephra layers occurring in marine to nearshore sequences of Wanganui Basin and deep???sea cores retrieved east of North Island. The identification of previously unrecognised mid???Pleistocene TVZ???sourced tephra deposits in the Auckland region, and their correlation to the offshore marine record, represent an advance in the construction of a higher resolution history for the TVZ where, close to eruptive source, the record is fragmentary and obscured by deep burial, or erosion, or both.

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  • The conservation status of New Zealand Hymenoptera

    Ward, Darren; Early, JW; Schnitzler, F-R; Hitchmough, RA; Stringer, IAN (2012-06)

    Journal article
    The University of Auckland Library

    Two species of New Zealand Hymenoptera, a colletid bee Leioproctus nunui and a gasteruptiid Gasteruption scintillans, are considered Threatened: both are ranked Nationally Critical. Twenty taxa are At Risk, comprising two taxa that are Declining with the remainder classified as Naturally Uncommon. A further 47 taxa are Data Deficient, and 669 known species are either Not Threatened or Introduced and Naturalised.

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  • DNA barcoding and the taxonomy of Microgastrinae wasps (Hymenoptera, Braconidae): Impacts after 8 years and nearly 20000 sequences

    Smith, MA; Fernandez-Triana, JL; Eveleigh, E; Gomez, J; Guclu, C; Hallwachs, W; Hebert, PDN; Hrcek, J; Huber, JT; Janzen, D; Mason, PG; Miller, S; Quicke, DLJ; Rodriguez, JJ; Rougerie, R; Shaw, MR; Varkonyi, G; Ward, Darren; Whitfield, JB; Zaldivar-Riveron, A (2013-03)

    Journal article
    The University of Auckland Library

    Microgastrine wasps are among the most species-rich and numerous parasitoids of caterpillars (Lepidoptera). They are often host-specific and thus are extensively used in biological control efforts and figure prominently in trophic webs. However, their extraordinary diversity coupled with the occurrence of many cryptic species produces a significant taxonomic impediment. We present and release the results of 8 years (2004???2011) of DNA barcoding microgastrine wasps. Currently they are the best represented group of parasitoid Hymenoptera in the Barcode of Life Data System (BOLD), a massive barcode storage and analysis data management site for the International Barcoding of Life (iBOL) program. There are records from more than 20 000 specimens from 75 countries, including 50 genera (90% of the known total) and more than 1700 species (as indicated by Barcode Index Numbers and 2% MOTU). We briefly discuss the importance of this DNA data set and its collateral information for future research in: (1) discovery of cryptic species and description of new taxa; (2) estimating species numbers in biodiversity inventories; (3) clarification of generic boundaries; (4) biological control programmes; (5) molecular studies of host-parasitoid biology and ecology; (6) evaluation of shifts in species distribution and phenology; and (7) fostering collaboration at national, regional and world levels. The integration of DNA barcoding with traditional morphology-based taxonomy, host records, and other data has substantially improved the accuracy of microgastrine wasp identifications and will significantly accelerate further studies on this group of parasitoids.

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  • Bronchiectasis exacerbation study on azithromycin and amoxycillin-clavulanate for respiratory exacerbations in children (BEST-2): Study protocol for a randomized controlled trial

    Chang, AB; Grimwood, K; Wilson, AC; van Asperen, PP; Byrnes, Catherine; O'Grady, K-AF; Sloots, TP; Robertson, CF; Torzillo, PJ; McCallum, GB; Masters, IB; Buntain, HM; Mackay, IM; Ungerer, J; Tuppin, J; Morris, PS (2013-02-20)

    Journal article
    The University of Auckland Library

    Background: Bronchiectasis unrelated to cystic fibrosis (CF) is being increasingly recognized in children and adults globally, both in resource-poor and in affluent countries. However, high-quality evidence to inform management is scarce. Oral amoxycillin-clavulanate is often the first antibiotic chosen for non-severe respiratory exacerbations, because of the antibiotic-susceptibility patterns detected in the respiratory pathogens commonly associated with bronchiectasis. Azithromycin has a prolonged half-life, and with its unique anti-bacterial, immunomodulatory, and anti-inflammatory properties, presents an attractive alternative. Our proposed study will test the hypothesis that oral azithromycin is non-inferior (within a 20% margin) to amoxycillin-clavulanate at achieving resolution of non-severe respiratory exacerbations by day 21 of treatment in children with non-CF bronchiectasis.Methods: This will be a multicenter, randomized, double-blind, double-dummy, placebo-controlled, parallel group trial involving six Australian and New Zealand centers. In total, 170 eligible children will be stratified by site and bronchiectasis etiology, and randomized (allocation concealed) to receive: 1) azithromycin (5 mg/kg daily) with placebo amoxycillin-clavulanate or 2) amoxycillin-clavulanate (22.5 mg/kg twice daily) with placebo azithromycin for 21 days as treatment for non-severe respiratory exacerbations. Clinical data and a parent-proxy cough-specific quality of life (PC-QOL) score will be obtained at baseline, at the start and resolution of exacerbations, and on day 21. In most children, blood and deep-nasal swabs will also be collected at the same time points. The primary outcome is the proportion of children whose exacerbations have resolved at day 21. The main secondary outcome is the PC-QOL score. Other outcomes are: time to next exacerbation; requirement for hospitalization; duration of exacerbation, and spirometry data. Descriptive viral and bacteriological data from nasal samples and blood inflammatory markers will be reported where available.Discussion: Currently, there are no published randomized controlled trials (RCT) to underpin effective, evidence-based management of acute respiratory exacerbations in children with non-CF bronchiectasis. To help address this information gap, we are conducting two RCTs. The first (bronchiectasis exacerbation study; BEST-1) evaluates the efficacy of azithromycin and amoxycillin-clavulanate compared with placebo, and the second RCT (BEST-2), described here, is designed to determine if azithromycin is non-inferior to amoxycillin-clavulanate in achieving symptom resolution by day 21 of treatment in children with acute respiratory exacerbations.Trial registration: Australia and New Zealand Clinical Trials Register (ANZCTR) number http://ACTRN12612000010897. http://www.anzctr.org.au/trial_view.aspx?id=347879. ?? 2013 Chang et al; licensee BioMed Central Ltd.

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  • Antibiotics for bronchiectasis exacerbations in children: rationale and study protocol for a randomised placebo-controlled trial

    Chang, AB; Grimwood, K; Robertson, CF; Wilson, AC; van Asperen, PP; O'Grady, K-AF; Sloots, TP; Torzillo, PJ; Bailey, EJ; McCallum, GB; Masters, IB; Byrnes, Catherine; Chatfield, MD; Buntain, HM; Mackay, IM; Morris, PS (2012-08-31)

    Journal article
    The University of Auckland Library

    Background: Despite bronchiectasis being increasingly recognised as an important cause of chronic respiratory morbidity in both indigenous and non-indigenous settings globally, high quality evidence to inform management is scarce. It is assumed that antibiotics are efficacious for all bronchiectasis exacerbations, but not all practitioners agree. Inadequately treated exacerbations may risk lung function deterioration. Our study tests the hypothesis that both oral azithromycin and amoxicillin-clavulanic acid are superior to placebo at improving resolution rates of respiratory exacerbations by day 14 in children with bronchiectasis unrelated to cystic fibrosis.Methods: We are conducting a bronchiectasis exacerbation study (BEST), which is a multicentre, randomised, double-blind, double-dummy, placebo-controlled, parallel group trial, in five centres (Brisbane, Perth, Darwin, Melbourne, Auckland). In the component of BEST presented here, 189 children fulfilling inclusion criteria are randomised (allocation-concealed) to receive amoxicillin-clavulanic acid (22.5 mg/kg twice daily) with placebo-azithromycin; azithromycin (5 mg/kg daily) with placebo-amoxicillin-clavulanic acid; or placebo-azithromycin with placebo-amoxicillin-clavulanic acid for 14 days. Clinical data and a paediatric cough-specific quality of life score are obtained at baseline, at the start and resolution of exacerbations, and at day 14. In most children, blood and deep nasal swabs are also collected at the same time points. The primary outcome is the proportion of children whose exacerbations have resolved at day 14. The main secondary outcome is the paediatric cough-specific quality of life score. Other outcomes are time to next exacerbation; requirement for hospitalisation; duration of exacerbation; and spirometry data. Descriptive viral and bacteriological data from nasal samples and blood markers will also be reported.Discussion: Effective, evidence-based management of exacerbations in people with bronchiectasis is clinically important. Yet, there are few randomised controlled trials (RCTs) in the neglected area of non-cystic fibrosis bronchiectasis. Indeed, no published RCTs addressing the treatment of bronchiectasis exacerbations in children exist. Our multicentre, double-blind RCT is designed to determine if azithromycin and amoxicillin-clavulanic acid, compared with placebo, improve symptom resolution on day 14 in children with acute respiratory exacerbations. Our planned assessment of the predictors of antibiotic response, the role of antibiotic-resistant respiratory pathogens, and whether early treatment with antibiotics affects duration and time to the next exacerbation, are also all novel.Trial registration: Australia and New Zealand Clinical Trials Register (ANZCTR) number ACTRN12612000011886.

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  • Microbial community structure in the gut of the New Zealand insect Auckland tree weta (Hemideina thoracica)

    Waite, David; Dsouza, M; Biswas, Kristi; Ward, Darren; Deines, P; Taylor, Michael (2015-05)

    Journal article
    The University of Auckland Library

    The endemic New Zealand weta is an enigmatic insect. Although the insect is well known by its distinctive name, considerable size, and morphology, many basic aspects of weta biology remain unknown. Here, we employed cultivation-independent enumeration techniques and rRNA gene sequencing to investigate the gut microbiota of the Auckland tree weta (Hemideina thoracica). Fluorescence in situ hybridisation performed on different sections of the gut revealed a bacterial communi ty of fluctuating density, while rRNA gene-targeted amplicon pyrosequencing revealed the presence of a microbial community containing high bacterial diversity, but an apparent absence of archaea. Bacteria were further studied using full-length 16S rRNA gene sequences, with statistical testing of bacterial community membership against publicly available termite- and cockroach-derived sequences, revealing that the weta gut microbiota is similar to that of cockroaches. These data represent the first analysis of the weta microbiota and provide initial insights into the potential function of these microorganisms.

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  • Long-term antidepressant use: Patient perspectives of benefits and adverse effects

    Cartwright, Patricia; Gibson, Kerry; Read, J; Cowan, O; Dehar, T (2016)

    Journal article
    The University of Auckland Library

    Long-term antidepressant treatment has increased and there is evidence of adverse effects; however, little is known about patients' experiences and views of this form of treatment. This study used mixed methods to examine patients' views and experiences of long-term antidepressant treatment, including benefits and concerns. Data from 180 patients, who were long-term users of antidepressants (3-15 years), were extracted from an anonymous online survey of patients' experiences of antidepressants in New Zealand. Participants had completed rating scales about the effectiveness of antidepressants, levels of depression before and during antidepressant use, quality of life, and perceived adverse effects. Two open-ended questions allowed participants to comment on personal experiences. The majority (89.4%) reported that antidepressants had improved their depression although 30% reported moderate-to-severe depression on antidepressants. Common adverse effects included withdrawal effects (73.5%), sexual problems (71.8%), and weight gain (65.3%). Adverse emotional effects, such as feeling emotionally numb (64.5%) and addicted (43%), were also common. While the majority of patients were pleased with the benefits of antidepressant treatment, many were concerned about these adverse effects. Some expressed a need for more information about long-term risks and increased information and support to discontinue.

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  • Reported outcomes of lower limb orthopaedic surgery in children and adolescents with cerebral palsy: A mapping review

    Wilson, Nichola; Chong, J; Mackey, AH; Stott, Ngaire (2014-09)

    Journal article
    The University of Auckland Library

    AIM: Lower limb surgery is often performed in ambulatory children with cerebral palsy (CP) to improve walking ability. This mapping review reports on outcome measures used in the published literature to assess surgical results, determine range and frequency of use, and map each measure to the International Classification of Functioning, Disability and Health. METHOD: A mapped review of literature published between 1990 and 2011 was carried out to identify papers reporting the outcomes of lower limb orthopaedic surgery in ambulatory children with CP, aged 0 to 20 years. RESULTS: A total of 229 published papers met the inclusion criteria. Thirty-two outcome measures with known psychometric properties were reported in the 229 papers. Twenty measures assess impairments in body structure and function and were used in 91% of studies. Ten measures assess restrictions in activity and participation and were used in 9% of papers. Two measures assessed quality of life. Since 1997, 29% of papers have used the Gross Motor Function Classification System to describe participants. INTERPRETATION: The body of literature evaluating outcomes of lower limb orthopaedic surgery in CP is small but increasing. There is a need to develop a suite of outcome measures that better reflect outcomes across the International Classification of Functioning, Disability and Health, including activity and participation.

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  • ???Ka hoki a Kupe???? The political career of Matiu Rata, 1963???1979

    McDowell, Tiopira (2015)

    Journal article
    The University of Auckland Library

    This article charts the political career of the Honourable Matiu Rata, R??tana???Labour MP and member for Northern M??ori between 1963 and 1979. Rata???s career is worthy of closer inspection, as it marks an important phase in the history of M??ori engagement with parliament and represents one of the high points of M??ori political achievement. To explain the twists and turns that came to typify the life of this complex and unpredictable figure we must look to his background and his early career. Understanding Rata???s personality and his dynamic politics in these early years is crucial to understanding the dramatic decision he made to leave the Labour Party in 1979. A greater awareness of the historical context and of the trend of politicians, historians and the media consistently undervaluing M??ori politicians helps to explain why Rata was able to pursue his goals where others had faltered, and why he was underestimated by his colleagues. Far more needs to be known about the politics, personality and career of this significant and influential M??ori politician and leader. Understanding his career in turn explains much about M??ori political engagement and the limitations of M??ori parliamentary representation.

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  • No effect of a whey growth factor extract during resistance training on strength, body composition, or hypertrophic gene expression in resistance-trained young men

    Dale, MJ; Coates, AM; Howe, PRC; Tomkinson, GR; Haren, MT; Brown, A; Caldow, M; Cameron-Smith, David; Buckley, JD (2017-06)

    Journal article
    The University of Auckland Library

    Growth factors can be isolated from bovine milk to form a whey growth factor extract (WGFE). This study examined whether WGFE promoted activation of the AKT/mTOR pathway enabling increased lean tissue mass and strength in resistance trained men. Forty six men with >6 months of resistance training (RT) experience performed 12 weeks of RT. Participants consumed 20 g/day of whey protein and were randomised to receive either 1.6 g WGFE/day (WGFE; n = 22) or 1.6 g cellulose/day (control, CONT; n = 24). The primary outcome was leg press one-repetition maximum (LP1-RM) which was assessed at baseline, 6 and 12 weeks. At baseline and 12 weeks body composition was assessed by dual energy x-ray absorptiometry, and muscle protein synthesis and gene expression were assessed (vastus lateralis biopsy) in a sub-sample (WGFE n = 10, CONT n = 10) pre- and 3 hr post-training. RT increased LP1-RM (+34.9%) and lean tissue mass (+2.3%; p < 0.05) with no difference between treatments (p > 0.48, treatment x time). Post-exercise P70s6k phosphorylation increased acutely, FOXO3a phosphorylation was unaltered. There were no differences in kinase signalling or gene expression between treatments. Compared with CONT, WGFE did not result in greater increases in lean tissue mass or strength in experienced resistance trained men.

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  • The relative importance of proactive behaviors and outcomes for predicting newcomer learning, well-being, and work engagement

    Cooper Thomas, Helena; Paterson, Nicole L; Stadler, Matthias J; Saks, Alan M (2014-06)

    Journal article
    The University of Auckland Library

    New employees can accelerate and optimize their socialization by behaving proactively, although the key behaviors vary across studies. Recent research suggests that newcomer proactive behaviors influence socialization through the mediating effect of corresponding proactive outcomes. This may partly explain differences across studies, along with possible variations in the relative importance of specific proactive behaviors. This study investigates further the mediating role of proactive outcomes, and the relative importance of different proactive behaviors and proactive outcomes in predicting newcomer learning, well-being, and work engagement. Based on a sample of 176 temporary agency workers, support for the mediating role of proactive outcomes was found, although some proactive behaviors were effective in their own right. Relative importance analyses revealed that different proactive behaviors were important for different socialization criteria. Practical and theoretical implications of these findings are discussed.

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  • Computer modelling integrated with micro-CT and material testing provides additional insight to evaluate bone treatments: Application to a beta-glycan derived whey protein mice model

    Sreenivasan, D; Tu, PT; Dickinson, Michelle; Watson, Maureen; Blais, A; Das, Rajarshi; Cornish, Jillian; Fernandez, Justin (2016-01)

    Journal article
    The University of Auckland Library

    The primary aim of this study was to evaluate the influence of a whey protein diet on computationally predicted mechanical strength of murine bones in both trabecular and cortical regions of the femur. There was no significant influence on mechanical strength in cortical bone observed with increasing whey protein treatment, consistent with cortical tissue mineral density (TMD) and bone volume changes observed. Trabecular bone showed a significant decline in strength with increasing whey protein treatment when nanoindentation derived Young??s moduli were used in the model. When microindentation, micro-CT phantom density or normalised Young??s moduli were included in the model a non-significant decline in strength was exhibited. These results for trabecular bone were consistent with both trabecular bone mineral density (BMD) and micro-CT indices obtained independently. The secondary aim of this study was to characterise the influence of different sources of Young??s moduli on computational prediction. This study aimed to quantify the predicted mechanical strength in 3D from these sources and evaluate if trends and conclusions remained consistent. For cortical bone, predicted mechanical strength behaviour was consistent across all sources of Young??s moduli. There was no difference in treatment trend observed when Young??s moduli were normalised. In contrast, trabecular strength due to whey protein treatment significantly reduced when material properties from nanoindentation were introduced. Other material property sources were not significant but emphasised the strength trend over normalised material properties. This shows strength at the trabecular level was attributed to both changes in bone architecture and material properties.

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  • Water use characteristics of a bamboo species (Bambusa blumeana) in the Philippines

    Dierick, D; H??lscher, D; Schwendenmann, Luitgard (2010-12-15)

    Journal article
    The University of Auckland Library

    We studied water use in a common bamboo species (Bambusa blumeana J.A. and J.H. Schultes) in the Philippines with the aim to (1) estimate bamboo water use and its dependence on environmental factors, (2) evaluate internal water storage and water dynamics and (3) compare water use characteristics of this bamboo species with those of co-occurring tree species. Two thermal sap flow methods were applied and complemented with a deuterium tracing experiment. Sap flow measured using the stem heat balance method (SHB) was in agreement with simultaneous flow measurements from thermal dissipation probes (TDP) which were used for long term measurements in this study. Maximal sap flux densities measured at the culm base using the TDP method were up to 25.7 g cm???2 h???1, but can be 2???3 times higher at other positions along the culm due to changes in the culm wall cross-section. Maximal water use rates of bamboo culms were on average 12 kg d???1, corresponding to a maximal transpiration rate of 1.4 mm d???1 at the clump level. These values are in line with those of co-occurring tree species, but bamboo tends to limit water use more under reduced soil water availability than most co-occurring tree species. Deuterium added to the transpiration stream at the culm base travelled upwards more slowly than in trees, leading to maximal deuterium levels in the canopy at the 3rd or 6th day after labelling, whereas this was the 1st or 2nd day for trees. This may indicate higher water storage capacities in bamboo relative to its water use rates, although diurnal patterns of sap flux density did not support this interpretation.

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  • Production lead-time hedging and coordination in prefabricated construction supply chain management

    Zhai, Y; Zhong, Runyang; Li, Z; Huang, GQ (2016-09-14)

    Journal article
    The University of Auckland Library

    This paper studies a coordination scheme to solve a production lead-time hedging (PLTH) issue in the prefabricated construction supply chain management. To mitigate tardiness delivery owing to prefab production uncertainty, the project contractor (PC) prefers to inform the prefab factory (PF) an earlier due date which is termed as PLTH strategy. However, this strategy forces the PF to compress its production process. A balance must be optimised through the proposed PLTH coordination scheme. It includes a PLTH-related cost term, i.e. crashing money (charged by the PF to the PC) and a constant transfer term. Three models with different power structures are considered. Firstly, two Stackelberg games with alternative decision-making sequences and an equal power model are discussed to obtain the optimal PLTH amount and crashing money. Later on, a cost-sharing term is used to fairly allocate the system surplus. It is observed that this coordination scheme reduces the PLTH amount and ensures win???win coordination for both parties. Some interesting managerial implications are also obtained from comparison analysis and numerical studies.

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  • The Effects of Maternal Under-Nutrition and a Post-Natal High Fat Diet on Lens Growth, Transparency and Oxidative Defense Systems in Rat Offspring

    Jayaratne, SK; Donaldson, Paul; Vickers, Mark; Lim, Julie (2017-04)

    Journal article
    The University of Auckland Library

    A poor early life nutrition environment is well established to result in a range of cardiometabolic disorders in offspring in later life. These effects can be exacerbated via exposure to an obesogenic dietary environment. To date, the effect of maternal diet and/or a post-natal obesogenic nutritional environment on key characteristics related to lens growth and oxidative stress has not been undertaken. The present study, therefore, examined the characteristics and oxidative status of the lens.Using a model of moderate maternal under-nutrition, rat dams were fed either a control diet (100% ad libitum, CON) or undernourished throughout pregnancy (50% of ad libitum intake, UN) and offspring fed either a control (5% fat, C) or high fat (30% fat, HF) diet post-weaning, resulting in four nutritional groups; CON-C, CON-HF, UN-C, and UN-HF. Offspring lenses were extracted at 160 days of age, weighed, imaged under dark and bright field microscopy, and then dissected into cortical and core fractions for biochemical analyses of oxidative stress markers.Our findings reveal that lenses from all groups were transparent. However, gender specific changes were evident at the biochemical level with increased oxidative stress detected in the cortex and core of female but not male UN-C lenses, and in the cortex of male but not female CON-HF lenses. The greatest increase in oxidative stress was detected in the UN-HF group in the cortex and core regions of the lens and for both genders.These findings show that oxidative stress is exacerbated in the lens as a result of a combination of altered pre-natal and post-natal diet. This demonstrates a novel interaction between the two developmental windows and warrants further investigations toward devising appropriate nutritional strategies for minimizing oxidative stress in the lens.

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