407 results for Undergraduate

  • Caesarean Delivery on Maternal Request: A New Zealand Perspective

    Dwight, Emily May (2017)

    Undergraduate thesis
    University of Otago

    In many countries, including New Zealand, the caesarean delivery rate far exceeds the current WHO recommendation of 10-15% of live births. This is causing concern amongst a number of parties. One of the explanations for the rate increasing so quickly and to such an extent is Caesarean Delivery on Maternal Request (CDMR). There have been no studies conducted on CDMR in a New Zealand context to date. This qualitative study explored the perceptions of a group of New Zealand obstetricians’ and midwives’ on CDMR. The information was obtained via 12 face-to-face semi-structured interviews. The maternity providers were asked if they had ever encountered requests, whether they believed that it was ever reasonable to accede to a request for a caesarean section in a low-risk pregnancy, and whether there was a place for these procedures in the public healthcare system. An ethical analysis followed thematic analysis of the data. The ethical justification for the interviewee’s responses was analysed in the light of the four principles of biomedical ethics as articulated by Beauchamp and Childress; autonomy, beneficence, non-maleficence and justice. The results of this study show that there is no standardized approach to CDMR in New Zealand, raising concerns about equity of access. For this reason the development and implementation of a national care pathway for CDMR is commendable.

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  • Modulation of DNA methylation by L-ascorbate and 5-aza-2’-deoxycytidine in murine embryonic stem cells

    Bridgman, Luke David (2017)

    Undergraduate thesis
    University of Otago

    Cytosine methylation, normally found on cytosine residues adjacent to guanine (i.e., a CpG dinucleotide), is one means by which long-term gene repression occurs. Immediately after semi-conservative DNA replication, CpG dinucleotides on the replicated daughter strand are unmethylated, giving the “hemimethylated” state, where one DNA strand is methylated and one unmethylated. Hemimethylation is usually corrected through complementary methylation by Dnmt1 maintenance methyltransferase, but oxidative stress can inhibit Dnmt1, and so replicated DNA will remain hemimethylated. The Morison laboratory had new evidence that this aberrant hemimethylated DNA is “corrected” by the Tet family of enzymes, which actively catalyse the conversion of parent strand 5-mC to 5-carboxylcytosine (5-cC), that is subsequently replaced with cytosine by base excision repair. This study developed a murine embryonic stem cell model through which the molecular basis of active demethylation could be investigated. It was hypothesised that Tet family enzymes actively demethylate DNA, following oxidative stress-mediated inhibition of Dnmt1; i.e., after the generation of hemimethylated DNA. To model oxidative stress-induced hemimethylation the Dnmt1 inhibitor decitabine was used. The effect of ascorbate on Tet activity, both alone and in conjunction with decitabine was also assessed. Ascorbate increases Tet activity by increasing regeneration of Fe2+, whilst decitabine (5-aza-2’-deoxycytidine) inhibits Dnmt1 by binding and sequestering it. We hypothesise that when Tet is activated using ascorbate and Dnmt1 is inhibited by decitabine the proportion of unmethylated DNA should increase, due to the creation of hemimethylated DNA by decitabine and the upregulation of Tet activity by ascorbate. To perform this research, murine embryonic stem (ES) cells were maintained and manipulated in cell culture. Cell lines were synchronised to G1 by thymidine block. ES cells received differential treatments: control culture, + decitabine, + ascorbate, and + decitabine / + ascorbate. Samples were extracted at 2, 4 and 6 hours post-release from thymidine synchronisation. Hairpin linkers were used to maintain the connection between complementary DNA strands throughout PCR amplification, allowing comparison of parent-daughter strand methylation to identify hemimethylated sequences. Hairpin linkers were synthesised for three highly methylated genes: Asz1, Ckt2 and Kcnv2. Two next-generation sequencing libraries were prepared, containing 144 and 288 samples respectively, and sequenced using the high-throughput Illumina MiSeq platform. Bisulfite-converted sequences were aligned using BiQ Analyzer HT software, and methylation symmetry in complementary DNA strands determined using RStudio. Methylation proportions were averaged and/or correlated with results for each replicate, and plotted. This project identified that ascorbate induced marked demethylation in ES cells, whilst decitabine caused large increases in hemimethylation, but no increase in demethylation. When decitabine was added in conjunction with ascorbate, increasing demethylation was observed. These findings demonstrate that decitabine has the potential to induce marked hemimethylation, even in wild-type cells, in ascorbate-deficient culture. There was also evidence to suggest that in the presence of hemimethylated target sequence, ascorbate is necessary to allow Tet activity. This was seen in Tet-Triple knockout ES cells, where ascorbate failed to induce demethylation. Overall, the results support the hypothesis that hemimethylated DNA has the potential to induce Tet enzyme activity.

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  • The role of anti-Müllerian hormone in the brain’s response to steroid hormones

    Sirisomboonwong, Korawan Erika (2017)

    Undergraduate thesis
    University of Otago

    Many sexual dimorphisms that exist in the brain develop in the postnatal period. For males, this is when testosterone levels are minimal and anti-Müllerian hormone (AMH) is elevated. Testosterone requires the enzyme aromatase to undergo conversion to oestradiol to exert masculinising effects on the brain. Hence, the effect of AMH on aromatase was investigated. Transgenic mice for the Type 2 AMH receptor (AMHR2) were used, with male AMHR2-/- mice compared to male and female AMHR2+/+ mice. Experimental groups included perinatal, pre-pubescent and adult mice to assess different hormonal environments. In situ hybridisation was utilised to assess the presence of aromatase. Radioactive in situ hybridisation showed that at 2 days old, there was a wide variation of aromatase expression within each genotype group. There were also similar levels of aromatase between the male AMHR2+/+ and AMHR2-/- mice. This indicates that the role of AMH is independent from aromatase. To confirm this, larger sample sizes would be used so statistical analysis could be performed. Location of AMH intracellular signalling molecules could be identified and genomic RNA studies could be used to assess the effect AMH has on neurons.

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  • Nanopore Sequencing of RNA from Breast Cancer Genes

    de Jong, Lucy Clair (2016)

    Undergraduate thesis
    University of Otago

    Abnormal mRNA splicing can disrupt gene function and influence the course of disease. Analysis of abnormal splicing is an important part of determining whether a particular genetic variant found in the population is pathogenic or not. However, to correctly identify abnormal splicing, we must first understand what is normal. This project assessed the isoforms of the genes BRCA1 and BARD1, which are particularly relevant to the onset of breast cancer. BRCA1 is a tumour suppressor gene implicated in breast cancer onset. BARD1 codes for a protein that interacts with BRCA1 and produces a smaller mRNA transcript. Normal exon skipping events have been identified for both BRCA1 and BARD1, however, current methods are unable to reliably identify full transcripts. This has resulted in knowledge of individual exon skipping events but often does not tell us whether multiple events occur in the same transcript. The MinION nanopore sequencer (Oxford Nanopore Technologies), uses a nanopore to produce long-read, single molecule sequences. This has great potential for identifying multiple long isoforms, which is not practical using current technologies. The aim of this project was to examine the ability of the MinION to identify mRNA splicing patterns of transcripts derived from BRCA1 and BARD1. All mRNA from a normal lymphoblastoid cell line was converted to cDNA and targeted genes of interest were amplified by polymerase chain reaction (PCR). All potential isoforms generated from BRCA1 and BARD1 were then pooled and analysed using the MinION sequencer. After trialling many different analysis methods, the read data was analysed using the BLAST-like Alignment Tool (BLAT) with two outputs, a tabular and a graphical format. The tabular format grouped reads into potential isoforms, while the graphical format allowed visualisation of these isoforms and identified the exon/intron boundaries. Using both these formats 34 BRCA1 isoforms and 39 BARD1 isoforms were identified, 24 and 17 of which were potential novel isoforms respectively. Two of these novel isoforms from the BRCA1 dataset (Δ10-17 and Δ11q21) were further verified using Sanger sequencing. This was a proof of principle research project that demonstrated the potential use of the MinION nanopore sequencer for successful characterisation of multiple mRNA isoforms. This research has successfully identified a number of novel isoforms from the BRCA1 and BARD1 genes using the MinION sequencing device.

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  • The effect of Mepitel Film on skin reaction severity in patients undergoing radiation therapy for head and neck cancer: a feasibility study

    Wooding, Hayley (2017)

    Undergraduate thesis
    University of Otago

    Radiation skin reactions are a common side effect of radiation therapy and can be distressing and painful for patients. Head and neck cancer patients receive a high dose of radiation to the skin and are therefore at high risk of acute skin toxicity. There have been many clinical trials investigating topical agents to reduce or prevent these reactions but the evidence to date is lacking and many centres still base their practice on anecdotal evidence. Recently clinical trials in breast cancer patients have shown that using Mepitel Film® (Mölnlycke Health Care AB, Gothenburg, Sweden) reduced skin reaction severity and stopped the development of moist desquamation when used prophylactically (from the first day of radiation therapy). Mepitel Film and other soft silicone dressings that adhere very closely to the folds of the skin, have been hypothesized to decrease skin reaction severity by stopping friction by clothing and allow the radiation damaged skin to repair itself. The aim of this randomised controlled feasibility study in this thesis was to investigate whether Mepitel Film dressings were superior to Sorbolene cream in reducing or managing radiation-induced skin reactions in patients with head and neck cancer Head and neck cancer patients are prescribed a higher dose than breast cancer patients, have an uneven surface for the Mepitel Film to adhere to and have complex non-homogenous dose distributions, This means that testing the effect of Mepitel Film in this cohort would be challenging. Despite this, it was hypothesised that Mepitel Film was superior to standard Sorbolene cream in decreasing the severity of acute radiation-induced skin reaction in patients receiving radiation therapy for head and neck cancer. In order to test this hypothesis a randomised, controlled, multi-centre, international, open label intra-patient feasibility study was conducted in New Zealand and China. This thesis analyses a subset of 12 patients recruited at the Canterbury Regional Cancer and Haematology Service (CRCHS) at Christchurch Public Hospital. For the first six patients, the study area was chosen as the area of first erythema which was divided into equal halves. Each half was randomised to either Mepitel Film or Sorbolene cream. Mepitel Film was applied as soon as erythema was visible (management protocol). For the next six patients, the study area was chosen at the planning stage to include an area of relatively uniform high dose (>40Gy). This area was divided into two equal halves; one half was randomised to Mepitel Film the other half to Sorbolene cream. Mepitel Film was applied from day one of radiation therapy treatment (prophylactic protocol). Sorbolene cream was applied twice a day by the patient. The Modified Radiation-induced Skin Reaction Assessment Scale (RISRAS) and the Modified Radiation Therapy Oncology Group (RTOG) skin toxicity score were used to assess skin reaction severity three times a week. Patients also filled out the New Zealand validated Distress screening tool once a week and completed exit questionnaires at the end of the follow-up period. Thermoluminescent dosimeters (TLDs) were used to measure the actual dose to the skin underneath Mepitel Film and the control cream for all patients. When results of all 12 patients were combined, there was a statistically significant decrease in skin reaction severity in favour of Mepitel Film of 29% for combined scores, of 15% for researcher scores and of 49% for patients’ scores (p= 0.001, 0.002 and 0.004 respectively). The difference in peak RISRAS score between skin covered with Mepitel Film and control skin covered in cream was also significantly lower (p=0.02). The results were disappointing compared to those reported by the breast cancer trial where skin reaction severity was reduced by more than 90% when Mepitel Film was used prophylactically. Several factors may explain the lack of effectiveness of the Mepitel Film in this patient cohort. Dose to the skin was significantly higher in head and neck cancer patients and Mepitel Film did not adhere well to skin with heavy beard stubble, which meant Mepitel Film needed to be replaced almost daily for the first few weeks of radiation therapy. The latter may also explain why there was no difference in the Mepitel Film effect between the skin of patients on the management protocol and those on the prophylactic protocol which should have had the strongest skin protective effect. In addition, compared with skin covering the breast area, skin in the neck area may be “tougher” and less likely to benefit from “friction protection”. The results suggest that Mepitel Film does reduce skin reaction severity in head and neck cancer patients but the increase in skin folds, beard growth and high skin dose mean that the protective effects of Mepitel Film are limited, particularly in men with heavy beard growth. Mepitel Film appeared to be more effective in women but there were too few women in this trial to perform a statistically meaningful analysis. Future research should include clinical studies in different cohorts of head and neck patients, such as in women and men with less beard growth.

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  • Predictors of Referral Delay and Treatment Response to Intravitreal Bevacizumab for Wet Age-Related Macular Degeneration

    Ang, Wee Choen (Sebastian) (2017)

    Undergraduate thesis
    University of Otago

    Background: Recent years have seen anti-vascular endothelial growth factor (VEGF) agents revolutionize the treatment of wet age-related macular degeneration (AMD). To ensure optimal outcomes for this time-sensitive disease, current guidelines recommend that patients should be seen in clinic within two weeks of referral and treated with a loading phase of three injections, followed by a follow-up visit for reassessment. However, meeting these guidelines is challenging due to the increasing global prevalence of wet AMD and the accumulating cohort of patients requiring treatment. In addition, services with inefficient referral pathways and limited treatment capacities have been shown to threaten patient access to prompt treatment and increase adverse patient outcomes. Aims and Methods: This project is a two-year retrospective audit conducted at the Eye Department in Dunedin Public Hospital with the aims to (1) assess the efficiency of the current wet AMD referral pathway against contemporary guidelines and (2) identify any risk factors that are predictive of referral delay and treatment outcome. Relevant patient, referrer, referral and clinical characteristics were retrieved from retrospective analysis of clinical records and OCT scans of 113 patients. The outcome measures were referral delay (i.e. duration from point of referral to first assessment clinic); and treatment response measured by changes in visual acuity, changes in central macular thickness (CMT) and clearance of macular fluid. All potential predictors of these outcome measures were analysed via multivariable binomial logistic regression. Results: Only 49% of patients at Dunedin Public Hospital met referral guidelines, but 85% met treatment guidelines. Overall median time from point of referral to first treatment was 10 days. A loading phase of three bevacizumab injections significantly improved mean visual acuity by 5 ± 24 letters (p=0.03) and reduced mean central macular thickness (CMT) by 55μm (p85 years) were associated with an increased likelihood of CMT reduction (OR 9.157; 95% CI 2.6, 31.747; p<0.001 and OR 4.79; 95% CI 1.11, 20.7; p=0.036 respectively), whereas patients with longer duration of symptoms (1 to 3 months) were significantly associated with a decreased likelihood of CMT reduction compared to patients with symptoms of less than one month (OR 1.65; 95% CI 0.044, 0.616, p value = 0.007). Thicker baseline CMT was also found to be significantly associated with a greater reduction of macular fluid (OR 1.475; 95% CI 0.75, 4.578; p=0.017) after treatment, and so were females compared to males (OR 3.9; 95% CI 1.2, 12.58; p=0.02). Conclusion: This study identified that the current wet AMD referral pathway at Dunedin Public Hospital can and should be more efficient, and quality improvement work is warranted to improve compliance to contemporary guidelines.

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  • Novel Organic Carbon Monoxide Releasing Molecules as a Potential Treatment for Triple Negative Breast Cancer

    Gunatunga, Kishan (2011)

    Undergraduate thesis
    University of Otago

    Carbon monoxide (CO) plays a role in many physiological and pathophysiological processes as a second messenger. Emerging evidence reveals the potential CO has as a therapeutic agent as it has been implicated in the modulation in a range of intracellular functions including apoptosis and proliferation. In the case of cancer, specifically triple negative breast cancer (TNBC), there is very little information regarding the effects of this molecule. Here we hypothesize that the targeted delivery of CO to a tumour will result in an anti-cancer effect in TNBC. The current study examines a novel class of compounds termed organic CO releasing molecules (CORMs) (CO-1 – CO-8) and previously published metal containing CORMs (CORM-2), as potential treatments for TNBC. Firstly a wide range of synthesised novel organic CORMs were screened for toxicity in MDA-MB-231 cells, a model for TNBC, and the lead compound CO-1 was identified from a range of 8 potential candidates (CO-1 – CO-8). Analysis of cell viability data revealed that CO-1 (1 – 200 μM) resulted in significant reductions in cell viability with an IC75 value of around 5 μM in the MDA-MB-231 TNBC cell line, while the by-product of CO-1, BP-1, demonstrated no residual cytotoxic effects. Time course and gas chromatograph-mass spectrometry (GC-MS) studies revealed that the compound released CO at a slow rate with a half-life in vitro between 9 and 24 hours. The ability of CO-1 and CORM-2 to modulate cell death via the induction of apoptosis was demonstrated using Annexin V conjugated to fluorescein (FITC) and propidium iodide (PI) staining followed by FACS analysis. CO-1 was able to induce apoptosis in MDA-MB-231 cells at both low (10 μM) and high (200 μM) concentrations (6% and 6% respectively) with no apoptotic or necrotic effects being observed when cells were treated with the by-product of CO-1, BP-1. The transition metal containing CORM-2 (200 μM) did not increase apoptotic markers compared to control, however treatment of cells with its “inactive” counterpart iCORM-2 (200 μM) resulted in a significant increase (7%) in apoptosis. In addition high (200 μM) but not low (5 and 10 μM) concentrations of CO-1 and CORM-2 produced a significant increase in the percentage of cells with a damaged mitochondrial membrane (3% and 5% for CO-1 and CORM-2 respectively), indicating that CO may have some concentration specific effects in vitro. High (200 μM) concentrations of both CO-1 and CORM-2 were also shown to induce mitochondrial damage in the MDA-MB-231 cell line and further to the potential anti-cancer effects of the novel compound CO-1, we have shown that low (10 μM) concentrations of the molecule causes a 1.2-fold and 1.4-fold increase in caspase 3 and p53 expression and a 1.2-fold increase in caspase 3 activation. The safety of both organic and transition metal CORMs were also assessed in the renal epithelial MDCK cell line. In MDCK cells treated with CO-1 (10 and 200 μM), COM-2 and iCORM-2 (20 and 100 μM) showed histopathological changes indicative of cell death were observed. These changes were not present in cells treated with the by-product of CO-1, BP-1. Interestingly the changes in histological architecture in MDCK cells treated with iCORM-2 appeared more extensive and severe that in cells treated with the active form of the compound CORM-2. Furthermore treatment of MDCK cells with low (10 μM) concentrations of CO-1, 20 and 200 μM CORM-2 and 200 μM iCORM-2 resulted in G2/M cell cycle arrest in the MDCK cell line. The current study proved CO-1, to be a safe and efficacious pharmacological agent with the ability to induce a cytotoxic and cytostatic effect in the MDA-MB-231 and MDCK cell line with no residual toxic effects resulting from treatment of cell with the by-product of CO-1 (BP-1). Our findings cast doubt over the notion that existing transition metal CORMs in their “inactive” form are not without biological effects. Therefore the current study has shown that novel organic CORMs have a combination of properties that translate into a desirable and potential treatment for TNBC.

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  • Men’s experience of virtual simulation to aid patient education for radiation treatment to the prostate

    Flockton, Alannah - Jayne (2017)

    Undergraduate thesis
    University of Otago

    Prostate cancer affects more than 3000 New Zealand men each year. Many of these men receive a complex type of radiation treatment which requires patients to have a full bladder and empty rectum to aid in the accuracy of treatment delivery and minimise side effects. These concepts can be difficult to explain and current patient education involves verbal and written materials. A 3D immersive teaching tool Virtual Environment Radiotherapy Training system (VERT) can visually simulate and demonstrate how radiation treatment is delivered to the prostate. There is sufficient evidence to support VERT as a useful teaching tool in the academic environment however; using VERT for one-on-one patient education is a novel approach. This qualitative, pilot study set out to explore men’s experience of VERT when it was incorporated into education sessions for prostate radiation treatment. More specifically, how VERT shaped the men’s understanding of how radiation treatment is delivered; why a full bladder and empty rectum is required; and their initial treatment experience. Data collection involved semi-structured interviews one week after the participants had experienced the VERT education and received their first week of radiation treatment. Interpretative phenomenological analysis (IPA) was used to offer insight into the men’s experience of the VERT education session. The findings strongly suggest VERT education enhances patient understanding of radiation treatment through visual learning. There is a preference to have the VERT education delivered sometime near the first treatment appointment and VERT has the potential to support men through engagement, information sharing and encouraging peer support. There is a role for visual tools such as VERT to be included as part of patient education sessions for radiation treatment to the prostate.

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  • Another Look at the Faunal Remains of CA-SCR-9

    Nims, Reno (2011-06)

    Undergraduate thesis
    The University of Auckland Library

    CA-SCR-9 is an important early Middle Period (3100-2800 cal BP) site from the California central coast region that has been used to characterize residential base camps from that time. Previous studies have attempted to analyze the fauna using incomplete and non-representative samples, creating multiple, contradictory conclusions about the foodways of Middle Period peoples. The goal of this study was to synthesize and analyze all identified material to answer questions about the seasonal use of SCR-9, differences between two possible phases of occupation, and the adaptive strategies of Middle Period peoples on the California central coast. Using a representative sample of the fauna, this paper finds that SCR-9‟s inhabitants primarily preyed upon mule deer. However, diverse species of marine mammals, leporids, terrestrial carnivores, birds, and marine fishes were also deposited at SCR-9, and inland site. The faunal remains from SCR-9 alone are not enough to identify relationships between sites, but these marine materials suggest that SCR-9 may have functioned as a seasonal or year round habitation site from which Middle Period peoples traveled to coastal sites such as SMA-218, which is nearly contemporaneous with SCR-9. Other writers have argued that two separate phases are represented ad SCR-9, including the Sand Hill Bluff Phase and the later Año Nuevo Phase. The fauna from these two phases is extraordinarily homogenous, suggesting there were no changes in adaptive strategy, or that rodent activity has mixed the materials, making it impossible to compare fauna from the Sand Hill Bluff and Año Nuevo phases. Fortunately, the assemblage does shed light on differential handling of taxa, and raises questions about the nature of bone grease extraction practices.

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  • Swaggers and society : a New Zealand experience

    Steven, Graeme D. (1979)

    Undergraduate thesis
    University of Otago

    The aims of this study are two-fold. First, to reach an understanding of the swagger, his lifestyle, and his outlook on life. And second, to investigate the relationships between the swagger and various groups in New Zealand society, in the late nineteenth and early twentieth centuries. The North Otago region was chosen as a base for the study because it has traditionally been regarded as one of the main swagger areas in New Zealand. The main town of Oamaru had a population of 4000 to 6000 in the 1890's, and was neither wholly urban or rural. As the service centre for the North Otago hinterland and a road, rail and sea centre, Oamaru had large numbers of itinerants, passing through the town. In the rural hinterland mixed cropping predominated, and this required large numbers of seasonal workers, which were drawn from outside the region. In Chapter One it is argued that rural itinerant workers were integrated into a rural structure that was both labour intensive and seasonal. Chapter Two discusses the characteristics which separate the swagger from other rural itinerants, which I have called, the "swag-carriers". In Chapter Three the conflict between the swagger and a developing bureaucracy, and middle class ideology in the late nineteenth century, is analysed. In Chapters Four and Five, the attitudes of rural and towns people towards the swagger are investigated. A model based on the value system of "reputation" and "respectability is used in Chapter Six to explain the ambivalence of attitudes towards the swagger, and to investigate an important aspect of the swagger psychology - his self esteem and his individuality.

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  • Falcon Forestry Carriage Series 2 : a case study of productivity and operation.

    Bolitho, Callum (2015)

    Undergraduate thesis
    University of Canterbury Library

    The multiple drivers of workplace safety and increasing productivity are resulting in increased mechanisation within the forestry industry. The use of motorised grapples in cable harvesting is an applicable mechanisation method to the large proportion of steep terrain harvesting in New Zealand. In this dissertation a time study of the Falcon Forestry Carriage Series 2 has been undertaken in order to access its productivity and operation. Mean values of productivity were found to be 54.9m³/PMH for wood extracted from the ground, 64.6m³/PMH for bunched wood and 75.6m³/PMH for excavator fed wood after adjustment for the cycle distance and accumulation type. Longer cycles were found to decrease productivity by 0.15m³/PMH for each meter of cycle distance. Utilisation in the study was found to be 56% of total time which was similar to previous studies. 15% of total study time was accounted for by operational delays, 7% by personal delays and 23% by mechanical delays. Mechanical problems with the carriage occurred 6 times and accounted for 171 minutes or 13.4% of total delay time. Mechanical delay breakdown was similar to that found by McFadzean (2012) who recorded that 15% of total delay time was attributable to carriage mechanical delays. During a study of Operator effect it was found that the inexperienced Operator 3 and Operator 4 had a productivity of 52.2% (not statistically significantly different) and 18.5% (p value <0.05). The effects of accumulation method and cycle distance upon productivity were found to be similar to the results of previous studies, as was the utilisation of time within the study.

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  • Understanding demand for wood products in New Zealand’s major log markets.

    Drummond, Ryan C.M. (2015)

    Undergraduate thesis
    University of Canterbury Library

    New Zealand’s forestry sector is largely reliant on the presence of a strong export market with 57% of the volume harvested being exported of which 99% goes to Japan, the Republic of Korea, China and India. This identifies the need to analyse demand in these countries to better understand their needs in the future. Consumption of wood products per capita is a commonly used metric for estimating demand and was used in this research. Volumes of imports, exports and production were collected from the Food and Agricultural Organisation of the United Nations (FAO) and data for a range of explanatory variables was collected from a variety of official sources. Historical trends in consumption identified that as countries develop socially and economically their consumption shifts from largely solid wood products such as sawn timber to more processed products such as wood-based panels and paper and paperboard. Consumption was modelled using linear regression techniques to develop models which could be used to forecast consumption in the future. A wide variety of potential explanatory variables were considered and the models presented represent the most effective of these. GDP per capita was found to be the single most effective explanatory variable being highly significant (p<0.01) in all models. Price was also found to be a strong determinant of consumption, understandable as price is a major component of supply and demand dynamics. Measures of construction activity were found to be related to consumption of sawn timber in all studied countries and for wood-based panels in Japan. Forecasts produced for consumption in Japan should be used as only an example of the capability of the models presented herein. More work is required to develop these equations into a form where they can be used to more accurately estimate future consumption.

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  • Comparing performance of seedlot types in the Kaingaroa Forest using ground pilots and aerial LIDAR : comparing the performance of open-pollinated, control pollinated and clonal seedlots in a plantation trial in the Kaingaroa forest utilising airborne LIDAR.

    Henderson, Theo J. A. (2016)

    Undergraduate thesis
    University of Canterbury Library

    Problem: As more improved planting stock such as clones and genetically improved seedlings are introduced to the market it is important to properly understand the benefits of each production type. Various breeding programmes make claims around performance of their seedlots but there is a shortage of literature around the performance of these production types in a plantation setting for most production species. Approach: One seedling, two cuttings, and 7 clonal varieties were compared in a plantation setting on a single site. The stand was measured via five permanent sample plots (PSPs) per seedlot. The seedlots were categorised by material production type and compared using pair-wise analysis to find statistically significant differences. The seedlots were then compared individually to find any intramaterial differences. Available aerial LIDAR was then used to estimate tree height for the total seedlot area and establish whether this was an accurate estimate. Average LIDAR height was then used to estimate tree height for each of the five PSPs to establish whether this would improve the prediction of heights and permit its use for large-scale evaluation of genetic material. Results: Categorising seedlots by material type there was no statistical difference for height performance but there was for DBH and basal area. Clones and open-pollinated seedlots showed superior performance over controlled-pollinated material, but not different from each other. Clones showed reduced height variability over non-clones. DBH and basal area variability was also reduced but the difference was only statistically significant versus open-pollinated seedlots. Comparing seedlots individually there was large variation in performance and variability within material types, with clones showing some superiority and non-clones inconsistent improvements. The LIDAR tree height model for whole seedlot area showed to be a significant predictor average PSP height but poorly predicted CV. Predicting PSP area provided with LIDAR improved correlations over whole stand predictions for both values. Implications: The performance superiority for clones over other production types in this trial is not as pronounced as previously suspected. Clones do, however, provide a more uniform crop. The LIDAR tree height model could be used for further analysis but not for height variability without further improvement. Result validity was, however, reduced by the lack of trial replication and randomisation. This is the key limitation and makes guaranteeing improvements are due to improved genetics (not environment) problematic.

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  • Factors which influence corewood stiffness in radiata pine.

    Jones, Grace (2016)

    Undergraduate thesis
    University of Canterbury Library

    Increasing stocking and competition with weeds significantly increased Hitman estimates of stiffness at the significance level α=0.05. Accuracy of models predicting Hitman from TreeTap measurements can be improved by customizing them for particular silvicultural regimes and diameter at 1.4m (DBH). Controlled factors: genetics, wind sway and fertilizer use, did not significantly influence Hitman estimates of stiffness. Tree height did not significantly influence stiffness estimates, but including DBH in prediction models improved models of stiffness estimates. Stiffness in 10 year old Pinus radiata stems was studied in an experiment with the following factors: genetics, herbicide/fertilizer use, stocking and wind sway. Acoustic velocity was used as an estimate of modulus of elasticity (MOE) and was estimated using 2 different tools: Hitman, a resonance based tool used on 2m log sections, and TreeTap, a time-of-flight based tool used on 1.2m outer-wood sections of standing trees. DBH and tree height were also recorded for each tree. Green density was measured using submersion in order to use the formula: MOE = green density∗ acoustic velocity² Stiffness estimates from TreeTap were strongly correlated with Hitman estimates, but were about 30% higher on average. The relationship between stiffness estimates from these tools changed with weed competition and with stocking. No significant difference in stiffness was found between the northwest and the southeast sides of the stems when using the TreeTap tool, and an average value for each tree was used for subsequent analyses. These findings are similar to those from other studies carried out on different sites, and to a previous destructive sample at the same site. There were a few major outliers, but despite these the final model relating TreeTap and Hitman estimates was significant (P<0.0001). Weed competition and stocking significantly affected the intercept (P=5.71e-05 and P=1.08e 05 respectively) of a model predicting Hitman values from TreeTap estimates of stiffness.

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  • A comparative study of the influence that motor-manual felling and mechanised felling has on stem breakage.

    Andrews, S. D. (2015)

    Undergraduate thesis
    University of Canterbury Library

    Motor-manual felling has been the predominate method of severing trees in the felling process of a forest harvesting operation. Yet this method has been coupled with numerous injuries and deaths, as trees can strike fallers during this task. An alternative felling method was developed in the form of mechanised tree felling, in an attempt to reduce the frequency of injuries. Subsequently, mechanised felling is poorly understood when compared to motor-manual felling upon the impact it has on stem breakage. 183 trees were assessed by measuring the frequency of breakage, height of the first break and the volume retention abilities of three felling treatments; motor-manual, mechanised felling out of the stand and mechanised felling into the stand. The effect that directional felling had upon the length to the first break was also investigated for motor-manual and mechanised felling out of the stand. The percentage of stems that broke once felled was 73%, 76% and 94% for motor-manual, mechanised out of the stand and mechanised into the stand felling respectively. The height at which the first break occurred for the aforementioned felling treatments was 71%, 71% and 69% of the total tree height. Mechanised felling out of the stand had the greatest volume retention ability with 94.5% of the trees total volume being below the first break. Followed by 93.7% for motor-manual and 91.9% for mechanised felling into the stand, however these differences were statistically insignificant (p=0.14). Lastly the length to the first break for motor-manual and mechanised felling out of the stand failed to statistically change when a tree was felled through a range of directions from downhill to uphill. The influence that motor-manual felling and mechanised felling out of the stand had on stem breakage is similar, yet mechanised felling into the stand had a much greater impact on the percentage of stems that broke. With further improvements in technology, it could be seen that the number of mechanised tree-felling operations over take motor-manual felling, as their impact on stem breakage is comparable.

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  • An investigation into the system production balance within three mechanised harvesting case studies.

    Malietoa, K. K. (2016)

    Undergraduate thesis
    University of Canterbury Library

    Safety issues and high costs of traditional harvesting methods have been driving mechanisation increases in New Zealand. However, productivity increases from mechanisation alters system productivity balance. This can result in underutilised machinery and cause an increase in harvesting costs in real terms. A time study was carried out to understand the system productivity balance between felling, extraction and processing and the factors affecting system component productivity rates, for three case studies. The three case studies observed were (1) a semi-mechanised cable yarder extraction operation, (2) a fully-mechanised swing yarder operation and (3) a fully-mechanised ground based operation. There were large production imbalances between felling, extraction and processing in all three case studies. Felling was the most productive system component, being 98%, 37% and 88% (case studies 1 to 3 respectively) more productive than the bottleneck. System bottleneck for case studies 1 and 3 was extraction, and processing for case study 2. The number of stems bunched, number of stems shovelled, wind throw interference and machine position shift affected felling cycle time. For every stem bunched, average productivity decreased by 35% (24m³/PMH) and 21% (20.9m³/PMH) for case studies 2 and 3 respectively. Every additional stem shovelled reduced felling productivity by 7.4m³/PMH for case study 2. Haul distance, the number of stems extracted and site factor affected extraction productivity. Haul distance and the number of stems extracted had significant impact on hourly productivity for all case studies. Site factor affected hourly productivity by 6.9m³ and 56.7m³ for case studies 1 and 3 respectively, largely attributed to the cable system employed and ground conditions. Processing was affected by the number of logs cut per stem and if delimbing occurred. Delimbing and each additional log processed, decreased productivity by 16% and 14% respectively. These three case studies showed that mechanised systems are often not well balanced and result in system components being underutilised. Companies can consider task strategies, or machine sharing between systems to minimise the effect on cost.

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  • Genetic parameter estimates for growth traits of Eucalyptus bosistoana : assessment of two progeny trials in Marlborough, New Zealand.

    Burgess, Jack (2015)

    Undergraduate thesis
    University of Canterbury Library

    This paper presents a follow up study to that was already completed by Luis et al. (2011). Luis et al (2011) investigated the survival of E. bosistoana half-sib families within two progeny trials in Marlborough, New Zealand. The study investigated genetic growth parameters of the same two progeny trials. Trees at Craven (progeny trial) were statistically taller and larger in diameter than Lawson (other progeny trial), which is likely to be a result of thinning occurring one year earlier at the Craven and Lawson North sites than at the Lawson East site. The progeny trials were set up into randomized incomplete blocks which allowed effective calculations of fixed and random effects from a mixed-effect linear model. The family, incomplete block and residual variances from the mixed-effect model made heritabilities of growth traits possible to calculate. Narrow sense heritabilities for diameter at breast height ranged from 0.13 to 0.18, while tree height heritabilities ranged from 0.1 to 0.17. The inter-site correlation of family performance was weak to moderate for both height;  Craven : Lawson North = 0.28  Craven : Lawson East = 0.44  Lawson East : Lawson North = 0.27 And diameter at breast height (dbh); Craven : Lawson North = 0.32 Craven : Lawson East = 0.39 Lawson East : Lawson North = 0.36 Heritabilities were weak to moderate for growth traits but there was substantial variation so selection is still likely to provide sufficient gain. Further studies will need to consider researching the genetic parameters of wood qualities of E. bosistoana.

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  • An analysis of vessel loading of export logs at four New Zealand ports.

    Duval, Alfred W. (2016)

    Undergraduate thesis
    University of Canterbury Library

    Over half of New Zealand’s annual harvest was exported as logs in 2015 (MPI, 2016). The large scale and economic importance of log exports highlights the importance of efficient port operations. Productive cycle elements for the log loading operation were defined. The vessel loading cycle was split into six elements: three ‘action elements’ (loading, tallying, and slinging), and three ‘carting elements’ between the ‘action elements’. Time study measurements were carried out at four New Zealand ports (Tauranga, Marsden Point, Gisborne, and Port Chalmers) to identify differences in productive time to load log export vessels. Port Chalmers wasn’t compared to the other ports as it was too different operationally. Loading had the longest productive element time, followed by slinging and tallying, and lastly the ‘carting elements’. Loading was uninfluenced by port but affected by log grade, length, operator skill, and the time of day. Tallying was significantly different between the three ports with Marsden Point fastest and Tauranga slowest. Slinging was quickest in Gisborne and faster whilst loading below-deck and during the daytime. Carting elements were heavily influenced by distance to or from log stack for all four ports. Tauranga displayed the fastest historic gross load rate (JASm³/hour) yet the slowest productive cycle time. Gross load rate is influenced by delays, volume per cycle, and productive cycle time. The difference in productive time and gross load rate could therefore be assumed to be from increased volume per cycle and/or reduced delays in Tauranga. Exporters are fined for loading slower than scheduled. This cost is greater when shipping rates are high as fines are based on shipping rates. A 5% increase in loading efficiency can save the exporter US$11,000 per vessel at historic maximum shipping rates.

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  • Native forest monitoring : tracking changes in native forest remnants.

    Arnold, T. A. H. (2016)

    Undergraduate thesis
    University of Canterbury Library

    Native forest monitoring is undertaken by forest companies as a requirement for certification of their forests by groups such as the FSC. It is important for companies to be able to track changes that are occurring to native forest remnants that are often spread throughout their operational plantation forest estate. Pan Pac tasked me with completing their 2016 native forest monitoring programme and review the results that have been collected since the programme was implemented in 2002. The objective of this was to both gain a better understanding of how the composition of the remnants in their5 estate is changing and to make recommendations on how the programme could be improved in the future. The majority of the 11 Permanent Sample Plots (PSPs) measured were in good or stable condition, several of which showed strong regeneration of the understory over the past 14 years. Three of the sites have been affected by heavy ungulate browsing (deer and/or goats), which has resulted in the continued suppression of the understory vegetation. While all current canopy layers of the PSP have not changed significantly, current and future disturbance such as ungulate browse could result in a change in composition from the current forest makeup. Ungulate browsing has been identified as the biggest driver of change in the native forest remnants within Pan Pac’s estate. To further examine to magnitude of this, exclosure plots could be established in impacted remnants to assess the effect of removal of browsing pests as a basis for Pan Pac to make decisions about future ungulate control. Continued monitoring of native forests is key to be able to identify as well as understand what is happening with native forest remnants. Tracking composition change is important as it allows the forest manager to target management practices such as ungulate control to combat non-natural changes that are occurring.

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  • The performance of blocks of clones in a radiata pine production forest.

    Farmery, Acacia (2015)

    Undergraduate thesis
    University of Canterbury Library

    Problem: Genetically identical clones of Pinus radiata are being planted in New Zealand plantation forests. There have been many clonal trials carried out; however there is a weakness in published literature surrounding the performance of clones in production blocks. Method: Five comparisons in four of Pan Pac Forests Products production forests were measured. Three comparisons were measured at age 4.5 years old and two were measured at 7.5 years old. There were six Forest Genetics clones and three different control-pollinated seedlots measured in these comparisons. Each comparison had a different number and selection of seedlots. There were six different traits measured for the trees; diameter at breast height over bark, height, acoustic velocity, straightness, branching habit, and malformation. The different traits were compared between the seedlots within each comparison. The differences in variation for diameter at breast height and modulus of elasticity were compared between clones and control-pollinated seedlots. Finally, the results by clone for the traits, excluding height, were compared to the expected performance supplied by Forest Genetics. Results: There were differences in performance between seedlots. Four clones performed well across a range of traits. One clone performed well in the 7.5 year old blocks but not in the 4.5 year old blocks. One clone did not perform well in size and stiffness. Clones were significantly less variable than control-pollinated seedlots for diameter at breast height but not for modulus of elasticity. The performance of each clone in Pan Pac Forest Products forests was very similar to the expected performance provided by Forest Genetics. Implications: There are clones that can produce desired yield, stiffness and form. Clones will provide a more uniform crop in diameter than control-pollinated seedlots. Pan Pac Forest Products can rely on Forest Genetics prediction of clonal performance as a guide to performance in their forests.

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