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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
251

The development and application of molecular markers for linkage mapping and quantitative trait loci analysis of important agronomic traits in oil palm (Elaeis guineensis Jacq.)

Gan, Siou Ting January 2014 (has links)
Oil palm (Elaeis guineensis) produces over five times more oil/year/hectare than oil seed rape and accounted for 33% of world vegetable oil production in 2011. Being a cross-pollinated perennial tree crop with long breeding cycles (typically 12 years) and a large planting area requirement (usually 143 palms/hectare), utilization of molecular technology could greatly improve the efficiency of oil palm breeding. In the present study, various approaches were used to develop molecular markers for genetic linkage mapping and QTL analysis, with the ultimate goal of marker-assisted selection in oil palm. Firstly, Representational Difference Analysis (RDA) and Amplified Fragment Length Polymorphism (AFLP) were coupled with Bulked Segregant Analysis (BSA) to try to identify marker(s) closely linked to the important shell-thickness gene. A novel combination of RDA with Roche 454 pyrosequencing enabled a more comprehensive study of the enrichment profiles compared to Sanger sequencing. Identification of >35% redundant sequences, repetitive sequences and organelle DNA suggested that subtractive hybridization and target enrichment of RDA were inefficient here, with the lack of elimination of common sequences masking the real difference products. The use of the AFLP method identified 29 primer pairs that yielded 49 putative shell-thickness related-polymorphic bands. A detailed analysis will need to be carried out to fully evaluate and validate these markers. The use of the relatively new Diversity Array Technology “Genotyping-By-Sequencing” (DArTSeq) platform through genotyping of two closely-related tenera self-pollinated F2 populations, 768 (n=44) and 769 (n=57), generated a total of 11,675 DArTSeq polymorphic markers of good quality. These markers were used in the construction of the first reported DArTSeq based high-density linkage maps for oil palm. Both genetic maps consist of 16 major independent linkage groups (total map length of 1874.8 and 1720.6 cM, with an average marker density of one marker every 1.33 and 1.62 cM, respectively), corresponding well with the 16 homologous chromosome pairs of oil palm (2n = 2x = 32; 14/16 chromosomes were confirmed by known location SSR markers). Preliminary quantitative trait loci (QTL) mapping of the yield and vegetative growth traits detected four significant and 34 putative as well as two significant and 30 putative QTLs for these small 768 and 769 populations, respectively. No common significant QTL were detected between the two closely-related controlled crosses which could have allowed combination of QTL across the two populations. Saturation of the shell-thickness (Sh) region with all available DArTSeq markers, as well as map integration around the Sh regions for both populations, identified 32 Single Nucleotide Polymorphism (SNP) and DArT markers mapped within a 5 cM flanking region of the Sh gene. Homology search of the DArTSeq marker sequence tag (64 bp) against the recently published oil palm genome assembly confirmed that 23 out of the 32 (72%) DArTSeq markers were located on the p5_sc00060 scaffold in which the SHELL gene was identified. The identified shell-thickness markers could be useful as molecular screening tools. This study demonstrated the potential and feasibility of using genomic resources available for genetic improvement of oil palm breeding programmes.
252

Identification, prevalence and impacts of viral diseases of UK winter wheat

Flint, Laura J. January 2014 (has links)
The potential for viruses to be causing the plateau in the yield of UK wheat (Triticum aestivum) was investigated. Mechanical inoculation of Cynosurus mottle virus to wheat cv. Scout and cv. Gladiator caused 83% and 58% reduction in the number of grains produced, highlighting the potential of viruses to cause disease and yield loss. Viruses historically detected in cereals in the UK were not found to be prevalent following real time reverse transcriptase polymerase chain reaction testing of 1,356 UK wheat samples from 2009-2012 using eleven assasys developed in the project. This included an assay for Cynosurus mottle virus, which was based on its complete genome sequence which was obtained for the first time in this project. Viruses detected were Barley yellow dwarf virus-MAV (6 samples) (BYDV-MAV), Barley yellow dwarf virus-PAV (6 samples) (BYDV-PAV) and Soil-borne cereal mosaic virus (12 samples) (SBCMV). There was a higher prevalence of viruses in the south, thought to be due to warmer temperatures which benefitted insect vectors and the molecular processes of infection. Viruses were most commonly detected in the variety JB Diego, perhaps because this variety has no known resistance to viruses. The low prevalence of known viruses could also have been because they were outcompeted or replaced by previously unknown ones. Next generation sequencing was used to test 120 samples from an organic site, including wheat, weeds and insects, to search for novel viruses. Testing of twelve storage regimes for insect traps using BYDV-PAV infected Sitobion avenae for recovery of PCR amplifiable RNA using 18S rRNA and BYDV-PAV assays found that 0.5 M EDTA was the most successful regime which was therefore used in the collection of samples for sequencing. Known viruses such as BYDV-PAV were detected along with some additional potentially novel viruses (eight possibly novel viruses or strains of viruses with four in wheat). One such virus was apparently present in 25% of all wheat samples tested, making it potentially very significant. This could be important for unlocking the yield potential of wheat because it could be a cryptic virus which is highly prevalent. In order to control the spread of viruses their methods of transmission must be understood, therefore testing of seeds and resulting plants from Cynosurus mottle virus infected material was done. Tests did not detect the virus, therefore it was concluded that seed transmission does not occur. However, further tests are required. In conclusion this study indicates that known viruses are not currently a major problem for UK winter wheat. However, novel viruses that are a problem may be detected in the future perhaps by next generation sequencing. Additonal viruses from abroad would add to the threat. The impact of all viruses in wheat may be greater in the future due to climate change.
253

Use of sentinel practices to obtain data regarding common clinical conditions and presentations in small animal consultations

Robinson, Natalie Jane January 2014 (has links)
Gathering data on the veterinary caseload will be useful in directing both future research and the veterinary curriculum. Previous studies have used clinical records to gather this data, but the validity of these methods remains unclear. Direct observation has been used to collect similar data in medicine and may be better able to capture the complexities of the consultation. The aim of the study was to determine the common patients, presentations, diagnoses and interventions during small animal veterinary consultations using direct observation. A network of 8 sentinel practices in England and Scotland was recruited. A tool allowing collection of data during direct observation of consultations was developed and piloted. The tool was used to gather data on patient characteristics, problems discussed, diagnoses made and outcomes selected. Practice visits were conducted to feedback results and stimulate discussion. Consultations were highly complex, with discussion of multiple problems, leading to a wide range of diagnoses and outcomes. Discussion of several problems appeared to be associated with increased consultation length. Preventive medicine was a common reason for presentation, and these consultations were amongst the most complex. A definitive diagnosis was not reached for most problems, yet actions were frequently taken. Feedback from the practices involved was positive, and discussions surrounding priorities for future research echoed the findings of the study. Direct observation of consultations allows caseload to be recorded in great detail, which may not be possible with other collection methods. The results are the first step in directing future research towards areas relevant to practitioners and will also be useful in guiding the veterinary curriculum. The way in which future research is conducted should take into account the realities of first opinion practice, such as the high frequency of comorbidity and polypharmacy, and low frequency of definitive diagnosis.
254

Effect of ozone on anthracnose physicochemical responses and gene expression in papaya (Carica papaya L.)

Ong, Mei Kying January 2014 (has links)
A study was conducted to investigate the effects of varying levels of ozone (0, 1.5, 2.5, 3.5 or 5.0 ppm) for 96 h on 1. the in vitro and in vivo growth of Colletotrichum gloeosporioides, the causal organism of anthracnose; 2. the reactive oxygen species generation and spore mitochondria of C. gloeosporioides using transmission electron microscope, fluorescence microscope and laser scanning confocal microscope; 3. the production of defence-related enzymes in papaya; 4. microbiological analysis on ozone-treated and non-treated papaya; 5. the biochemical, physiological, gas exchange and sensory characteristics of papaya fruit during storage (25 ± 3 °C, 70 ± 5 %RH) for 14 days; 6. the changes in total phenols, total carotenoids and antioxidant activity; and 7. gene expression of ozone-fumigated papaya fruit. Data were analyzed using analysis of variance and differences among treatment means were separated by Duncan Multiple Range Test (DMRT). The results of antifungal studies showed that mycelial growth of C. gloeosporioides was reduced significantly (p < 0.05) at all concentrations compared to the control. The maximum inhibition in mycelium growth (41.2 %) was obtained at 5.0 ppm ozone. Similarly, conidial germination inhibition was 100 % for 5 ppm ozone. In vivo analysis revealed that 2.5 ppm ozone was the optimal concentration for controlling anthracnose disease incidence (72.5 %) and disease severity after 10 days of storage, showing that a moderate concentration of ozone is effective in the reduction of C. gloeosporioides in artificially inoculated papaya fruit without affecting the quality aspect of the fruit. The results of scanning electron microscopy (SEM) also confirmed that ozone fumigated fungus at levels above 3.5 ppm deformed and disintegrated spore and mycelia structure. Further to that, transmission electron microscopy (TEM) illustrated that the mitochondria of ozonized fungus was disintegrated and had ruptured membrane. In spores treated with 3.5 ppm ozone, mitochondrial cristae were distorted, whereas the mitochondria were almost completely degraded in spores treated with 5.0 ppm. Meanwhile, the results from microscopy studies using laser scanning confocal microscope and fluorescence microscope showed that ozone treatment caused production of reactive oxygen species (ROS) in mitochondria of C. gloeosporioides. With increased concentration of ozone, higher levels of ROS were induced in the spores. Besides its direct antifungal activity, the study strongly suggested that ozone induces a series of defense reactions through production of compounds such as total phenols, polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) in ozone-fumigated papaya. Likewise, content of ascorbic acid, β-carotene, lycopene and antioxidant activity of papaya increased as fruit ripened and was further enhanced by exposure to ozone for 96 hours from day 4 until day 8. Twenty-four hours of ozone treatment at the level of 0.5, 2, 3.5 and 5.8 ppm reduced the total mesophilic microorganism counts of fruit with initial values of 4.48 to 2.18 log cfug-1. In addition, no coliform bacteria were initiated after 24 hours at all levels of ozone exposure. In addition, 2.5 ppm ozone treated fruit showed maximum beneficial effects in reducing weight loss, maintaining firmness, reduced rate of respiration, delaying changes in peel colour and containing the highest soluble solids concentration (SSC) as compared to the control. The titratable acidity declined throughout the storage period with slower rate in ozone-fumigated fruits. Overall sensory assessment of quality after ripening showed fruit were significantly better in quality when fumigated with 2.5 ppm ozone which were assigned highest sensory score in terms of appearance, sweetness, pulp colour, texture, aroma and overall acceptability than the control. The discovery of the gene expression of papaya in defense response induced by ozone fumigation has further clarified the understanding on how specific gene involved in controlling its expression when the plant changes during stress or in any plant lifecycle event. Among those genes, some involved in ethylene biosynthesis, generation of reactive oxygen species and stress responses of plant defense were found (mitochondrion, chloroplast, heat shock proteins, polygalacturonase-inhibiting protein, hydroxyproline-rich glycoprotein, ethylene responsive factor and acyl-CoA oxidase). Thus, the findings from all the experiments carried out during this study showed that 2.5 ppm ozone reduced anthracnose incidence and extended the storage life for up to 12 days while maintaining acceptable quality of papaya fruit. Ozone exposure at 1.5 ppm resulted in poorer quality fruit as compared to 2.5 ppm ozone treated fruit. Higher concentration of ozone exposure at 3.5 ppm and 5 ppm ozone seems non-physiological and caused phytotoxic effect on the quality of papaya fruit. As a non-toxic, biodegradable product, eco-friendly and safe sanitizer, ozone has the potential to become a natural preservative for prolonging the shelf life and retaining quality of papaya by combating fungal disease, particularly fungus C. gloeosporioides, thus promoting the marketability of the crop and minimizing postharvest losses in the papaya industry.
255

Developing chitosan based green fungicides to control pre- and postharvest anthracnose of dragon fruit

Zahid, Noosheen January 2014 (has links)
A study was conducted to develop an ecofriendly and sustainable fungicide based on submicron chitosan dispersions using low molecular weight chitosan and locally prepared chitosan. The physicochemical properties of both submicron dispersions were determined and their antimicrobial effect on Colletotrichum gloeosporioides was also investigated. The antifungal effect was further demonstrated by the production of fungal cell wall degrading enzymes and by the production of defence related enzymes in the plants along with the effect of submicron chitosan dispersions on the vegetative growth of plants. The effect of submicron chitosan dispersions on biochemical and physiological responses of dragon fruit during storage at 10 ± 2 °C and 80 ± 5% relative humidity for 28 days was also investigated. In vitro antifungal activity of submicron chitosan dispersions showed that low molecular weight chitosan has better antifungal properties than the locally prepared chitosan and therefore was selected for further studies. However, 600 nm droplets of 1.0% chitosan showed promising results in terms of suppressing mycelial growth (90.2%), conidial germination (93.1%) and reducing dry weight of mycelium (37.9%). Similarly, in vivo studies showed that the 600 nm droplets of 1.0% chitosan helped to reduce the disease incidence by up to 33.0 %. Beside the direct antifungal effect, this study suggests that the submicron chitosan dispersions enhanced host resistance through the production of defence related compounds, such as total phenols, peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL) and also the activity of pathogenesis related proteins, such as β, 1-3 glucanase and chitinase. Treatments with submicron chitosan dispersions as 600 nm droplets of 1.0% chitosan showed more vigorous growth of plants as compared to the control. The submicron chitosan dispersions with 600 nm droplets of 1.0% chitosan helped to reduce the incidence of disease on fruit by up to 94% as compared to the control. The biochemical and physiological studies of dragon fruit after 28 days of storage showed that weight loss of the fruit treated with 600 nm droplets of 1.0% chitosan compared with the control reduced two fold but this was not significantly different from the conventional chitosan. The same trend was observed in all the parameters tested, including antioxidant activity. Control of disease using submicron chitosan dispersions has the potential to add market value to fresh produce. The findings from all the experiments showed that 600 nm droplets of 1.0% chitosan help to reduce anthracnose in the field and also during postharvest storage. Thus, 600 nm droplets of 1.0% chitosan could be used commercially in fields of dragon fruit as a green fungicide. Being non-toxic and biodegradable, chitosan has the potential to become an alternative to synthetic fungicides for protecting fruit crops and thus assisting sustainable agriculture.
256

Women and consumption : the rise of the department store and the #new woman' in Japan 1900-1930

Tamari, Tomoko January 2002 (has links)
The aim of this research is to seek to situate women in the development of consumer culture in Japan in the period 1900-1930. This period saw the beginnings of mass consumption and the rise of what was to become one of its central institutions, the department store. One of the most important department stores to emerge was Mitsukoshi, which provided a site in which the new tastes and lifestyles of consumer culture and western modernity could be looked at, sampled and practiced. In effect the store could be seen as providing a new form of 'intimate public sphere' for women. Mitsukoshi also provided images and information on the new consumer culture classifications and learning processes through its house magazines. Other magazines, especially women's magazines, whose readership rapidly expanded in this period, reinforced this message. The extent to which women were seen as the central operators of the emerging consumer culture is a central focus of the thesis. The department stores were not only spaces for women to consume, but also to work. The emergence of saleswomen as a new category of working woman is also discussed. The ways in which an image of a new women emerged as they became employed in greater numbers in the new service occupations and became more visible in the city centre streets and consumption and entertainment sites, is also considered. One variant here was the 'modem girl,' whose image was both discussed and constructed in the media by intellectuals, writers and cultural intermediaries. One of the aims of this work is to sketch out the parameters of this process in Japan and ask how far the stores and other new urban spaces, along with the mediated sources such as magazines, newspapers and the cinema, helped to further some shift (however limited and temporary) in the balance of power between the sexes towards women, along with a concomitant redefinition of what it meant to be a women. The new woman, then, occupied a contested space which a number of parties sought to define: the consumer culture industries such as the department stores, press and cinema; the government with its various thrift and everyday life reform campaigns designed to keep women in the home, albeit as skilled housewives; the various movements for greater women's rights and reform, both in the middle class and the working class militant women workers; the intellectuals and cultural intermediaries, some of whom saw the 'modem girl,' as a new exciting phenomenon of urban modernity; and, of course, the women themselves, who not only reacted to these forces, but gained in their capacity and desire to have a greater say in the process and control over their own lives
257

In vitro culture and transformation studies of spinach (Spinacia oleracea L.)

Knoll, Kirsten Angela January 1995 (has links)
The objective of the present study was to develop a comprehensive and reproducible regeneration system for spinach (Spinacia oleracea L. ) from commercially important cultivars and to assess the potential use of spinach for Agrobacterium tumefaciensmediated transformation. Tissue cultures of spinach were initiated from seed material. Axenic shoot cultures of spinach were established on MS-based medium containing 1.0 VM NAA at a temperature of 15°C and under a 16 h photoperiod. These three parameters were found most suitable for the establishment of shoot cultures and the encouragement of axillary shoot growth. Attempts to enhance axillary shoot production of spinach were investigated by the use of a double phase culture system, employing semi-solid and liquid culture media. The application of liquid medium was feasable with a volume of 5 ml for a duration of 7 or 14 d or with a volume of 10 ml for a duration of 7 d, but the multiplication rate of spinach was not increased. Adventitious shoot production was initiated from cultured spinach root explants derived from axenic shoots or hypocotyl explants. Sections from root tips and middle segments exhibited the highest shoot regeneration capacity when cultured on Nitsch and Nitsch (1969) medium supplemented with 20 μM NAA and 5.0 QCM GA3. Histological analysis demonstrated that the regenerating shoots originated directly from the root explants. Adventitious shoots were rooted on MS-based medium containing 1.0 μM NAA and transferred to the glasshouse, where the plants were grown to maturity. Seeds collected from regenerated plants were 95 % viable, producing a homgenous, fertile Rl-generation. Flow cytometric analysis was used to determine ploidy levels of regenerated plants and their progenies and showed that spinach leaf tissue from all generations displayed an even proportion of Go/G1 cells and G2/M cells, which may be characteristic for this species. Transformation studies using in vitro derived spinach explants demonstrated a positive response using two strains of Agrobacterium tumefaciens. The highest transformation rate was achieved with 25 % of explants being GUS-positive, therefore confirming susceptibility of spinach to the binary vector containing both T-DNA border sequences. It was found that best results were obtained with root explants which had been incubated for 8 weeks prior to co-cultivation with Agrobacterium and in vitro material which had been maintained in culture for up to 2 years. This reproducible regeneration system for spinach and the demonstration that spinach is amenable to Agrobacterium-mediated transformation provides the basis for potential commercial application within spinach breeding, aiming to generate an improved crop plant.
258

Learning in third space : the nature of non-formal learning opportunities afforded to e-learning leaders in the workplace

Anagnostopoulou, Kyriaki January 2014 (has links)
Institutional initiatives set up to meet the demands of a fast changing higher education (HE) landscape do not comfortably sit within a single academic or administrative department but instead require blended professionals, with a mixed portfolio of work, to operate in third space – between the administrative and academic domains of institutions (Whitchurch, 2008). Heads of e-Learning (HeLs) in UK HE institutions are one such group of professionals who lead the enhancement of learning and teaching through the use of technology. However, one must question how HeLs continue to learn and develop in their roles as transformational leaders to meet the continuous demands posed by the ever-changing HE environment and the evolution of technology. This research explored the affordances of third space as a learning environment, questioned how learning and leadership development take place through non-formal workplace experiences, and sought to relate these back to HeLs’ perceived developmental needs. The concept of liminality (van Gennep, 1960; Turner, 1969) was employed as a theoretical framework, learning was conceptualised as socially constructed identity formation and leadership development was deemed to be a result of learning. A mixed methodological approach was employed and a unique analytical framework shed light on data derived from nine in-depth interviews. Third space environments were found to be ‘expansive’ (Evans et al., 2006), with qualities which afforded transformational learning experiences that permanently altered the ways in which one understands the world around them. Liminal conditions in third space environments provided a means of reconciling a leader’s espoused theories and their theories-in-use, whilst leadership development was linked to learner readiness and the development of credibility. Underpinned by participatory practices, the theory of ‘possible selves’ (Ibarra, 2004) offered a means of understanding transformational learning and development in third space, and brought the concept of leadership closer to active citizenship.
259

Emotion and the New Testament : a critique of the interpretation of emotion in New Testament studies and an interpretation of the use of emotion in the New Testament

Elliott, Matthew January 2002 (has links)
The study of emotion in psychology and philosophy has seen major advancements in the last twenty years. This has included a new emphasis on the strong cognitive element that is present in all emotions. In large part, this dissertation is an attempt to bring the valuable findings of recent research to our understanding of emotion in the New Testament. The stated goal is to understand, in a broad sense, the use of emotion in the New Testament and how the writers perceived it. To this end, the writer surveys the ideas about emotion that were present in the Greco-Roman world, the Old Testament, and Intertestamental Judaism. The understanding of emotion by some important figures in church history is also studied. This background is then used to gain insight into the use of emotion in the New Testament. Specific, basic emotions are analyzed in the text; including love, joy, hope, jealousy, fear, anger, hatred, and sorrow. This is not a series of articles in the pattern of TDNT, but rather an analysis of emotion in general that uses specific emotions to study the subject in the New Testament. Interwoven into this study is a critique of the understanding of emotion that is predominant in New Testament studies. It is concluded that the New Testament has an appropriate and vital place for emotion in the Christian life. New Testament ethics, interpretation, and theology have often de-emphasized emotion, and this has been a mistake. A strong argument for the importance of emotion in the interpretation of the New Testament is made.
260

Genetic diversity and demographic history of the dromedary camel (Camelus dromedarius)

Almathen, Faisal January 2014 (has links)
The dromedary camel (Camelus dromedarius) commonly referred to as ‘ship of the desert’ has played an important part in the development and expansion of trading networks across inhospitable habitats over 3000 years, linking Arabian, Asian, African and European civilisations. Caravan roads, which are part of the major trading networks, have facilitated livestock exchange across large geographic distances. Dromedary camels are known to have been extensively used as pack animals along these caravan roads. Archaeological records point towards the southern Arabian Peninsula as the origin of the domestic dromedary camels. However, there is uncertainty about the dromedary’s dispersal out of the Arabian Peninsula to Africa and other parts of Asia. In contrast to other livestock species, the domestication of the dromedary camel has not been investigated using genetic evidence. Also, there is no information available on the genetic relationship between dromedary populations across their entire geographic distribution. Previous genetic studies were limited to a restricted number of animals, often from a single population or a small geographic region within countries. The general aims of this thesis were to characterise the origin and the geographic distribution of genetic diversity in dromedary camels and to understand the demographic history across the species range. To ascertain the global genetic structure and to contribute to the knowledge on the spread of the species after domestication, we sampled 1,083 modern-day dromedary camels from 21 countries representing the species range. Mitochondrial DNA and microsatellite markers were used for these analyses. Nine hundred and seventy animals were investigated using 17 autosomal microsatellite loci, and 759 animals were studied at the mitochondrial DNA level using a continuous 867 bp fragment spanning the end of cytochrome b, the tRNAs threonine and proline, and the beginning of the control region.

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