286 results for ResearchCommons@Waikato, Modify

  • Investigating diet as the source of tetrodotoxin in Pleurobranchaea maculata

    Khor, Serena; Wood, Susanna A.; Salvitti, Lauren R.; Taylor, David I.; Adamson, Janet E.; McNabb, Paul; Cary, S. Craig (2014)

    Journal article
    University of Waikato

    The origin of tetrodotoxin (TTX) is highly debated; researchers have postulated either an endogenous or exogenous source with the host accumulating TTX symbiotically or via food chain transmission. The aim of this study was to determine whether the grey side-gilled sea slug (Pleurobranchaea maculata) could obtain TTX from a dietary source, and to attempt to identify this source through environmental surveys. Eighteen non-toxic P. maculata were maintained in aquariums and twelve were fed a TTX-containing diet. Three P. maculata were harvested after 1 h, 24 h, 17 days and 39 days and TTX concentrations in their stomach, gonad, mantle and remaining tissue/fluids determined using liquid chromatography-mass spectrometry. Tetrodotoxin was detected in all organs/tissue after 1 h with an average uptake of 32%. This decreased throughout the experiment (21%, 15% and 9%, respectively). Benthic surveys at sites with dense populations of toxic P. maculata detected very low or no TTX in other organisms. This study demonstrates that P. maculata can accumulate TTX through their diet. However, based on the absence of an identifiable TTX source in the environment, in concert with the extremely high TTX concentrations and short life spans of P. maculata, it is unlikely to be the sole TTX source for this species.

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  • Whole genome sequencing of Mycobacterium tuberculosis reveals slow growth and low mutation rates during latent infections in humans

    Colangeli, Roberto; Arcus, Vickery L.; Cursons, Raymond T.; Ruthe, Ali; Karalus, Noel; Coley, Kathy; Manning, Shannon D.; Kim, Soyeon; Marchiano, Emily; Alland, David (2014)

    Journal article
    University of Waikato

    Very little is known about the growth and mutation rates of Mycobacterium tuberculosis during latent infection in humans. However, studies in rhesus macaques have suggested that latent infections have mutation rates that are higher than that observed during active tuberculosis disease. Elevated mutation rates are presumed risk factors for the development of drug resistance. Therefore, the investigation of mutation rates during human latency is of high importance. We performed whole genome mutation analysis of M. tuberculosis isolates from a multi-decade tuberculosis outbreak of the New Zealand Rangipo strain. We used epidemiological and phylogenetic analysis to identify four cases of tuberculosis acquired from the same index case. Two of the tuberculosis cases occurred within two years of exposure and were classified as recently transmitted tuberculosis. Two other cases occurred more than 20 years after exposure and were classified as reactivation of latent M. tuberculosis infections. Mutation rates were compared between the two recently transmitted pairs versus the two latent pairs. Mean mutation rates assuming 20 hour generation times were 5.5X10⁻¹⁰ mutations/bp/generation for recently transmitted tuberculosis and 7.3X10⁻¹¹ mutations/bp/generation for latent tuberculosis. Generation time versus mutation rate curves were also significantly higher for recently transmitted tuberculosis across all replication rates (p = 0.006). Assuming identical replication and mutation rates among all isolates in the final two years before disease reactivation, the u20hr mutation rate attributable to the remaining latent period was 1.6×10⁻¹¹ mutations/bp/generation, or approximately 30 fold less than that calculated during the two years immediately before disease. Mutations attributable to oxidative stress as might be caused by bacterial exposure to the host immune system were not increased in latent infections. In conclusion, we did not find any evidence to suggest elevated mutation rates during tuberculosis latency in humans, unlike the situation in rhesus macaques.

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  • Technology education in New Zealand

    Jones, Alister; Moreland, Judy (2002)

    Journal article
    University of Waikato

    Technology in New Zealand schools is a new area of learning that is now compulsory for all students (years 1–10). Technology education policy was first developed in 1992 (Jones & Carr, 1993). Since then there has been a sustained research and development focus to inform the structure of the curriculum, its subsequent national implementation, and classroom practice. This article discusses the structure of the technology curriculum, programs that were developed to inform teachers of the curriculum and its content, and strategies to enhance the classroom practice of technology.

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  • Technology education in New Zealand

    Forret, Michael; Jones, Alister; Moreland, Judy (2002)

    Journal article
    University of Waikato

    Technology is one of the seven essential learning areas included to achieve the knowledge and understanding that all New Zealanders need to acquire (Ministry of Education, 1993). Responsibility for the implementation of these curricula rests with schools which have flexibility in making implementation decisions. Within the national curriculum framework, all curriculum statements must reflect the principles of the national curriculum framework, specify clear learning outcomes against which students’ achievements can be assessed, have learning outcomes or objectives defined over eight progressive levels, and be grouped in a number of strands. The national curriculum framework’s principles relate to learning and achievement, development of school programs, and aspects of social justice and equity.

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  • High-resolution coproecology: Using coprolites to reconstruct the habits and habitats of New Zealand’s extinct upland Moa (Megalapteryx didinus)

    Wood, Jamie R.; Wilmshurst, Janet M.; Wagstaff, Steven J.; Worthy, Trevor H.; Rawlence, Nicolas J.; Cooper, Alan (2012)

    Journal article
    University of Waikato

    Knowledge about the diet and ecology of extinct herbivores has important implications for understanding the evolution of plant defence structures, establishing the influences of herbivory on past plant community structure and composition, and identifying pollination and seed dispersal syndromes. The flightless ratite moa (Aves: Dinornithiformes) were New Zealand's largest herbivores prior to their extinction soon after initial human settlement. Here we contribute to the knowledge of moa diet and ecology by reporting the results of a multidisciplinary study of 35 coprolites from a subalpine cave (Euphrates Cave) on the South Island of New Zealand. Ancient DNA analysis and radiocarbon dating revealed the coprolites were deposited by the extinct upland moa (Megalapteryx didinus), and span from at least 6,368±31 until 694±30 ¹⁴C years BP; the approximate time of their extinction. Using pollen, plant macrofossil, and ancient DNA analyses, we identified at least 67 plant taxa from the coprolites, including the first evidence that moa fed on the nectar-rich flowers of New Zealand flax (Phormium) and tree fuchsia (Fuchsia excorticata). The plant assemblage from the coprolites reflects a highly-generalist feeding ecology for upland moa, including browsing and grazing across the full range of locally available habitats (spanning southern beech (Nothofagus) forest to tussock (Chionochloa) grassland). Intact seeds in the coprolites indicate that upland moa may have been important dispersal agents for several plant taxa. Plant taxa with putative anti-browse adaptations were also identified in the coprolites. Clusters of coprolites (based on pollen assemblages, moa haplotypes, and radiocarbon dates), probably reflect specimens deposited at the same time by individual birds, and reveal the necessity of suitably large sample sizes in coprolite studies to overcome potential biases in diet interpretation.

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  • Does Socrates vindicate the coherence theory of truth?

    Deane, Warren (2011)

    Journal article
    University of Waikato

    Within Plato's Socratic Dialogues we routinely observe the character of Socrates employing a formal, yet largely unexplained method of investigation into the beliefs that his interlocutors hold as true. Socrates even goes so far as to claim there will be discord within them their whole life should they not be able refute one of his controversial and counter-intuitive revealed truths. With the beliefs under investigation striking to the core of how one should live a good life, this paper seeks to investigate whether Socrates' formal method justifies him in making the claims he does. After exposing the methodology of his technique, we turn to investigate the theory of truth that the method represents, seeking to ascertain a greater understanding of what truth means to Socrates when he makes the claim that a belief is true.

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  • Growth in densely populated Asia: implications for primary product exporters

    Anderson, Kym; Strutt, Anna (2013)

    Journal article
    University of Waikato

    Economic growth and integration in Asia is rapidly increasing the global economic importance of the region. To the extent that this growth continues and is strongest in natural resource-poor Asian economies, it will add to global demand for imports of primary products, to the benefit of (especially nearby) resource-abundant countries. How will global production, consumption and trade patterns change by 2030 in the course of such economic developments and structural changes? We address this question using the GTAP model and Version 8.1 of the 2007 GTAP database, together with supplementary data from a range of sources, to support projections of the global economy from 2007 to 2030 under various scenarios. Factor endowments and real gross domestic product are assumed to grow at exogenous rates, and trade-related policies are kept unchanged to generate a core baseline, which is compared with an alternative slower growth scenario. We also consider the impact of several policy changes aimed at increasing China's agricultural self-sufficiency relative to the 2030 baseline. Policy implications for countries of the Asia-Pacific region are drawn out in the final section.

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  • Retention and intentions of professional accountants

    Twiname, Linda J.; Samujh, Helen; Van Lamoen, Nils Karel (2012-06-30)

    Conference item
    University of Waikato

    This paper enhances understanding of factors underlying professional accountants’ high turnover rates. Various researchers, institutions and government bodies have identified accountants’ retention is of concern. However, traditional explanations, such as job satisfaction and organizational commitment, do not sufficiently account for the turnover rates observed in the accounting profession. A New Zealand (NZ) sample of professional accountants enabled us to identify a range of factor. Intentions to stay were very low, 50% of accountants expected to leave their current employer within 3 years of the survey date. Satisfaction with two core job characteristics, feedback and skill variety, in addition to work life balance (WLB) accounted for 65% of the variance of overall job satisfaction. WLB, or at least a lack of access to flexible work arrangements was strongly indicated as the primary consideration when choosing to remain with the present employer.

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  • Exploring the IT usage in SMEs from New Zealand, Columbia and Chile using action-research methodology

    Cataldo, Alejandro; Sepúlveda, Marcos; McQueen, Robert J. (2012)

    Journal article
    University of Waikato

    The theory on the adoption and use of information technology (IT) in small and medium enterprises (SMEs) is abundant. However, methodologically speaking, action-research (AR) has been little explored as a method of construction of this theory, despite the use of this methodology could improve understanding of how SMEs use IT. Therefore, we researched the use of IT in SMEs using a methodology adapted from AR. The methodology was tested in companies from New Zealand, Colombia and Chile. The use of this methodology was well evaluated by the top management of SMEs, in fact, the recommendations coming from the analysis were well received by the management of participants. These results are auspicious regarding the use of AR in SMEs and could help encourage other researchers to use this methodology, which remains little used in information systems research.

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  • Dataset for: Southern Hemisphere bog persists as a strong carbon sink during droughts

    Goodrich, Jordan Paul; Campbell, David I.; Schipper, Louis A. (2017)

    Unclassified
    University of Waikato

    Main article is available online at https://hdl.handle.net/10289/11373

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  • History and development of cooperative business in New Zealand: A case study of Allied Farmers Limited

    Reddy, Krishna; Locke, Stuart (2013)

    Journal article
    University of Waikato

    Cooperatives have been a feature of New Zealand agricultural scene since late 19th century. Although cooperatives did arise in a greater degree in the agricultural sector in New Zealand, evidence show that it has been not too different to that found in other jurisdictions. Using a case study methodology, this study analyses the history and development of cooperative business and explores the establishment and demise of Allied Farmers Limited in New Zealand. Using agency-theoretical perspective and hubris it is argued that Allied Finance Limited’s expansion was of concern from the start and was most likely to cause financial crisis. The evidence supports the view that the managerial overconfidence was the key factors leading to the demise of Allied Farmers Company Limited.

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  • Corporate governance – Performance relationship in microfinance institutions (MFIs)

    Thrikawala, Sujani Sudhara; Locke, Stuart; Reddy, Krishna (2013)

    Journal article
    University of Waikato

    The relationship between governance and the performance of microfinance institutions (MFIs) is discussed in this paper. MFI performance encompasses both financial performance and outreach. Good governance in terms of strengthening stewardship, achievement of MFIs’ primary objectives and promoting further development of the industry have been asserted as key elements in the literature pertaining to MFI performance. Similarly, several cases concerning poor governance have been analysed. Good corporate governance has become more important due to the demand for transparency and accountability of funds utilised in microfinance activities. Further, MFIs need to have a solid governance framework to minimise the possibilities of management failures which may jeopardise the efficacious application of received funds from governments and donors. In prior studies, the nature of corporate governance practised by MFIs is less understood and no substantive work using multiple MFI outcomes over a number of years has been undertaken. The concerns raised in reviews of individual MFIs and normative discussions of what should constitute best practice do point to the need for better understanding of the nature of corporate governance practised by the MFIs and also, to understand the nature of the relationship that exists between institutional success and corporate governance especially for developing countries. This study therefore identifies and provides a framework for undertaking corporate governance research relating to MFIs.

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  • Considerations for sustainable tourism development in developing countries: Perspectives from the South Pacific

    Panakera, Charlie; Willson, Gregory Brian; Ryan, Chris; Liu, Ge (2011)

    Journal article
    University of Waikato

    Nations of the South Pacific face a number of major challenges with respect to sustainable tourism development. Much of the literature presents overtly pessimistic conceptualisations of South Pacific nations as environmentally vulnerable and economically dependent. This paper argues that the narrative concerning sustainable tourism development in the South Pacific is incomplete and the predominant narrative viewing the South Pacific nations as economically and environmentally vulnerable is too simplistic. Additionally, this paper challenges the narrative that high or mass levels of tourism within the South Pacific cannot be sustainable. Based on experience derived from operational experience and consultancy, this paper provides insights into the challenges and possibilities for sustainable tourism development in the South Pacific.

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  • Watch, listen and learn: Observing children’s social conduct through their communication

    Bateman, Amanda (2011)

    Journal article
    University of Waikato

    This paper argues for the use of conversation analysis (CA) and membership categorisation analysis (MCA) (Sacks, 1992) to investigate children’s social conduct. A majority of prior research in this area has tended to focus on limited theoretical perspectives situated in developmental psychology, resulting in a dichotomous presentation of either prosocial or antisocial behaviour (see Bateman & Church, 2008 for an overview). Although the use of predefined categories “antisocial” and “prosocial” may be helpful for the organisation of data, there is a concern that these pre-defined classifications lead to children themselves being categorised as either consistently prosocial or antisocial (for example Nelson & Crick, 1999). This view encourages stigma and the labeling of children rather than offering further insight into children’s social worlds (Bateman & Church, 2008). This problem represents a shortfall in information regarding the complexity of peer interactions and how they are locally managed by the children themselves, disregarding the range of social competencies engaged in by the participants. Therefore a shift in theoretical approach is argued for here as this informs of how social order is produced through verbal and non-verbal communications between the participants themselves (Butler, Fitzgerald & Gardner, 2009; Sacks, 1992a; 1992b;). Analyzing children’s social conduct through observing their communication offers an innovative, theoretical shift which is becoming more valued in many different areas of early childhood and particularly for the study of social relationships in education. This paper will outline the concept of communication as perceived from an ethnomethodological (EM) perspective, provide a background to EM and conversation analysis (CA), discuss some findings from research and then discuss the practical application of these findings for practice.

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  • The Structure of the Oligomerization Domain of Lsr2 from Mycobacterium tuberculosis Reveals a Mechanism for Chromosome Organization and Protection

    Summers, Emma Louise; Meindl, Kathrin; Usón, Isabel; Mitra, Alok K.; Radjainia, Mazdak; Colangeli, Roberto; Alland, David; Arcus, Vickery L. (2012)

    Journal article
    University of Waikato

    Lsr2 is a small DNA-binding protein present in mycobacteria and related actinobacteria that regulates gene expression and influences the organization of bacterial chromatin. Lsr2 is a dimer that binds to AT-rich regions of chromosomal DNA and physically protects DNA from damage by reactive oxygen intermediates (ROI). A recent structure of the C-terminal DNA-binding domain of Lsr2 provides a rationale for its interaction with the minor groove of DNA, its preference for AT-rich tracts, and its similarity to other bacterial nucleoid-associated DNA-binding domains. In contrast, the details of Lsr2 dimerization (and oligomerization) via its N-terminal domain, and the mechanism of Lsr2-mediated chromosomal cross-linking and protection is unknown. We have solved the structure of the N-terminal domain of Lsr2 (N-Lsr2) at 1.73 Å resolution using crystallographic ab initio approaches. The structure shows an intimate dimer of two ß-ß-a motifs with no close homologues in the structural databases. The organization of individual N-Lsr2 dimers in the crystal also reveals a mechanism for oligomerization. Proteolytic removal of three N-terminal residues from Lsr2 results in the formation of an anti-parallel β-sheet between neighboring molecules and the formation of linear chains of N-Lsr2. Oligomerization can be artificially induced using low concentrations of trypsin and the arrangement of N-Lsr2 into long chains is observed in both monoclinic and hexagonal crystallographic space groups. In solution, oligomerization of N-Lsr2 is also observed following treatment with trypsin. A change in chromosomal topology after the addition of trypsin to full-length Lsr2-DNA complexes and protection of DNA towards DNAse digestion can be observed using electron microscopy and electrophoresis. These results suggest a mechanism for oligomerization of Lsr2 via protease-activation leading to chromosome compaction and protection, and concomitant down-regulation of large numbers of genes. This mechanism is likely to be relevant under conditions of stress where cellular proteases are known to be upregulated.

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  • Technical note: A significance test for data-sparse zones in scatter plots

    Vetrova, V. V.; Bardsley, W. Earl (2012)

    Journal article
    University of Waikato

    Data-sparse zones in scatter plots of hydrological variables can be of interest in various contexts. For example, a well-defined data-sparse zone may indicate inhibition of one variable by another. It is of interest therefore to determine whether data-sparse regions in scatter plots are of sufficient extent to be beyond random chance. We consider the specific situation of data-sparse regions defined by a linear internal boundary within a scatter plot defined over a rectangular region. An Excel VBA macro is provided for carrying out a randomisation-based significance test of the data-sparse region, taking into account both the within-region number of data points and the extent of the region. Example applications are given with respect to a rainfall time series from Israel and also to validation scatter plots from a seasonal forecasting model for lake inflows in New Zealand.

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  • Tetrodotoxin Concentrations in Pleurobranchaea maculata: Temporal, Spatial and Individual Variability from New Zealand Populations

    Wood, Susanna A.; Taylor, David I.; McNabb, Paul; Walker, Jarrod; Adamson, Janet E.; Cary, S. Craig (2012)

    Journal article
    University of Waikato

    Tetrodotoxin (TTX) is a potent neurotoxin that has been identified in a range of phylogenetically unrelated marine and terrestrial organisms. Tetrodotoxin was recently detected in New Zealand in Pleurobranchaea maculata (the grey side-gilled sea slug). From June 2010 to June 2011 wild specimens were collected from 10 locations around New Zealand. At one site (Narrow Neck Beach, Auckland) up to 10 individuals were collected monthly for 6 months. Attempts were also made to rear P. maculata in captivity. Tetrodotoxin was detected in samples from eight of the ten sites. The highest average (368.7 mg kg⁻¹) and maximum (1414.0 mg kg⁻¹) concentrations were measured in samples from Illiomama Rock (Auckland). Of the toxic populations tested there was significant variability in TTX concentrations among individuals, with the highest difference (62 fold) measured at Illiomama Rock. Tetrodotoxin concentrations in samples from Narrow Neck Beach varied temporally, ranging from an average of 184 mg kg⁻¹ in June 2010 to 17.5 mg kg⁻¹ by December 2010. There was no correlation between TTX levels and mass. The highest levels correspond with the egg laying season (June–August) and this, in concert with the detection of high levels of TTX in eggs and early larval stages, suggests that TTX may have a defensive function in P. maculata. Only one larva was successfully reared to full maturation and no TTX was detected.

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  • Increased Inter-Colony Fusion Rates Are Associated with Reduced COI Haplotype Diversity in an Invasive Colonial Ascidian Didemnum vexillum

    Smith, Kirsty Fiona; Stefaniak, Lauren; Saito, Yasunori; Gemmill, Chrissen E.C.; Cary, S. Craig; Fidler, Andrew E. (2012)

    Journal article
    University of Waikato

    Considerable progress in our understanding of the population genetic changes associated with biological invasions has been made over the past decade. Using selectively neutral loci, it has been established that reductions in genetic diversity, reflecting founder effects, have occurred during the establishment of some invasive populations. However, some colonial organisms may actually gain an ecological advantage from reduced genetic diversity because of the associated reduction in inter-colony conflict. Here we report population genetic analyses, along with colony fusion experiments, for a highly invasive colonial ascidian, Didemnum vexillum. Analyses based on mitochondrial cytochrome oxidase I (COI) partial coding sequences revealed two distinct D. vexillum clades. One COI clade appears to be restricted to the probable native region (i.e., north-west Pacific Ocean), while the other clade is present in widely dispersed temperate coastal waters around the world. This clade structure was supported by 18S ribosomal DNA (rDNA) sequence data, which revealed a one base-pair difference between the two clades. Recently established populations of D. vexillum in New Zealand displayed greatly reduced COI genetic diversity when compared with D. vexillum in Japan. In association with this reduction in genetic diversity was a significantly higher inter-colony fusion rate between randomly paired New Zealand D. vexillum colonies (80%, standard deviation ±18%) when compared with colonies found in Japan (27%, standard deviation ±15%). The results of this study add to growing evidence that for colonial organisms reductions in population level genetic diversity may alter colony interaction dynamics and enhance the invasive potential of newly colonizing species.

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  • Reduced Cortisol and Metabolic Responses of Thin Ewes to an Acute Cold Challenge in Mid-Pregnancy: Implications for Animal Physiology and Welfare

    Verbeek, Else; Oliver, Mark Hope; Waas, Joseph R.; McLeay, Lance M.; Blache, Dominique; Matthews, Lindsay R. (2012)

    Journal article
    University of Waikato

    Background: Low food availability leading to reductions in Body Condition Score (BCS; 0 indicates emaciation and 5 obesity) in sheep often coincides with low temperatures associated with the onset of winter in New Zealand. The ability to adapt to reductions in environmental temperature may be impaired in animals with low BCS, in particular during pregnancy when metabolic demand is higher. Here we assess whether BCS affects a pregnant animal’s ability to cope with cold challenges. Methods: Eighteen pregnant ewes with a BCS of 2.760.1 were fed to attain low (LBC: BCS2.360.1), medium (MBC: BCS3.260.2) or high BCS (HBC: BCS3.660.2). Shorn ewes were exposed to a 6-h acute cold challenge in a climate-controlled room (wet and windy conditions, 4.460.1uC) in mid-pregnancy. Blood samples were collected during the BCS change phase, acute cold challenge and recovery phase. Results: During the BCS change phase, plasma glucose and leptin concentrations declined while free fatty acids (FFA) increased in LBC compared to MBC (P,0.01, P,0.01 and P,0.05, respectively) and HBC ewes (P,0.05, P,0.01 and P,0.01, respectively). During the cold challenge, plasma cortisol concentrations were lower in LBC than MBC (P,0.05) and HBC ewes (P,0.05), and FFA and insulin concentrations were lower in LBC than HBC ewes (P,0.05 and P,0.001, respectively). Leptin concentrations declined in MBC and HBC ewes while remaining unchanged in LBC ewes (P,0.01). Glucose concentrations and internal body temperature (Tcore) increased in all treatments, although peak Tcore tended to be higher in HBC ewes (P,0.1). During the recovery phase, T4 concentrations were lower in LBC ewes (P,0.05). Conclusion: Even though all ewes were able to increase Tcore and mobilize glucose, low BCS animals had considerably reduced cortisol and metabolic responses to a cold challenge in mid-pregnancy, suggesting that their ability to adapt to cold challenges through some of the expected pathways was reduced.

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  • Understanding and ameliorating non-linear phase and amplitude responses in AMCW Lidar

    Godbaz, John Peter; Cree, Michael J.; Dorrington, Adrian A. (2012)

    Journal article
    University of Waikato

    Amplitude modulated continuous wave (AMCW) lidar systems commonly suffer from non-linear phase and amplitude responses due to a number of known factors such as aliasing and multipath inteference. In order to produce useful range and intensity information it is necessary to remove these perturbations from the measurements. We review the known causes of non-linearity, namely aliasing, temporal variation in correlation waveform shape and mixed pixels/multipath inteference. We also introduce other sources of non-linearity, including crosstalk, modulation waveform envelope decay and non-circularly symmetric noise statistics, that have been ignored in the literature. An experimental study is conducted to evaluate techniques for mitigation of non-linearity, and it is found that harmonic cancellation provides a significant improvement in phase and amplitude linearity.

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