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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.
1

Promoting tourism in the south coast region of KwaZulu-Natal through tour operators

Dimaza, Goitsemang Rosemary 14 January 2015 (has links)
Submitted in fulfillment of the requirements for the Degree of Masters in Business Administration, Durban University of Technology, 2014. / This study is an attempt to shed light on how tour operators can help to promote tourism in the south coast region of KZN. Even though tourism claims to bring economic development to the tourist destinations, in some cases, the development of tourism has created important social transformation in the other sectors of the tourism destinations, where the relationship between other sectors of the tourism industry and tour operators was weak or even negative. For some people, this situation is no longer considered a sustainable way to travel and do business. Therefore, the tour operator’s business does not end at picking up and dropping off tourists at their booked accommodation. The aim is to explore the role of tour operators in promoting tourism in the south coast region of KZN. The objectives of the study are: to identify and examine the nature of the tour operators’ business; to identify and explore the role of tour operators in the tourism industry in sustaining their businesses; to identify the changes needed to improve the promotion and sustainability of both tourism in the south coast region of KZN and that of the tour operator; and to explore the challenges encountered by tour operators which hinder effective contribution to the economy of South Africa. This research explored and investigated the perceptions of the tour operators in the south coast region in KZN in terms of their business growth, their role as tour operators and the problems they may encounter in growing their small businesses. A quantitative research methodology was utilised to collect the primary data for this study. Data was collected through the use of a structured questionnaire. The sample size for the study was 50 tour operators. The results from the literature and primary study revealed some interesting findings from the objectives and each set of questions. The highlighted finding in the study revealed the need for tour operators to provide the best possible service as the tourists are important for the destination’s economy (TOI, 2008:108). The study revealed that tour operators have direct contact with clients when they take them on tours; hence, a personal one-on-one safe relationship is established with clients (Moutinho, 2011:161). The conclusions drawn from this study point to the lack of access to information that would enable the majority of tour operators to understand the tourism sector holistically. Furthermore, information available to tour operators owing to technological advancements has increased exponentially (e.g. internet access).
2

Statistical evaluation of tribological effects of some fluids on sliding aluminium alloys

Lee, Peter John January 1998 (has links)
No description available.
3

Bioassay, properties, and isolation studies of a growth factor in tobacco

Murashige, Toshio. January 1958 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1958. / Typescript. Abstracted in Dissertation abstracts, v. 19 (1959) no. 7, p. 1530. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 86-94).
4

Effect of residual Gibrel X-47 on the germination and seedling growth of two cotton (Gossypium hirsutum L.) cultivars

Srivalope, Phrayune, 1938- January 1970 (has links)
No description available.
5

Effect of growth substances on the rooting response of alfalfa cuttings

al-Tabbakh, Abdelmoneim Elsayed, 1930- January 1964 (has links)
No description available.
6

Plant growth stimulating substances related to kinetin

Siehr, Donald Joseph, January 1957 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1957. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
7

The effects of aminoethoxyvinylglycine (AVG) and 1-methylcyclopropene (1-MCP) on banana ripening

26 May 2010 (has links)
M.Sc. / Bananas are climacteric fruit which are characterised by a low rate of ethylene production and respiration during the pre-climacteric phase, followed by a sudden burst in ethylene production and respiration during ripening. Ethylene is a gaseous plant hormone that accelerates the ripening of climacteric fruit. In order to extend the shelf life of bananas the action or synthesis of ethylene must be inhibited or delayed. Examples of such inhibitors are 1- methylcyclopropene (1-MCP) an inhibitor of ethylene action, and aminoethoxyvinylglycine (AVG), an inhibitor of ethylene synthesis. The purpose of this research was to compare the effect of these two inhibitors on ripening of bananas. 1-MCP acts by blocking the ethylene receptors permanently. The results of this study indicated that 500 nL.L-1 1-MCP is more effective in delaying ripening of banana than AVG, although AVG delivered a better quality fruit in terms of colour. To be effective, bananas must be pre-treated with 1-MCP before they exposed to ethylene. The results also indicated that, the effectiveness 1-MCP to delay ripening decreases with storage time. The results show that ethylene binding to its membrane bound receptors is reversible if the exposure time to ethylene is less than 8 hours. Exposure to ethylene for 8 hours or more results in irreversible binding. However, binding only becomes permanent when exposure to ethylene exceeds 16 hours. For this reason treatment with 1-MCP becomes ineffective after exposure to ethylene for 24 hours due to the fact that ethylene has bound irreversibly and permanently to its binding sites and cannot be displaced by 1-MCP.
8

The effect of the plant growth promoting rhizobacteria (PGPR) on Nicotiana benthamiana viral susceptibility

Nyamuvurudza, Spiwe January 2017 (has links)
A dissertation submitted in partial fulfilment of the requirements of the degree of Master of Science in Environmental science School of Animal, Plant and Environmental Sciences University of Witwatersrand, Johannesburg. March 2017. / Plant growth promoting rhizobacteria (PGPR) promotes plant growth in a variety of modes of action and also suppresses several phytopathogens causing plant diseases. There is evidence that Pseudomonas strains are able to induce systemic resistance, thereby enhancing the defensive capacity of many plant species, and they do so without any negative impact on the environment. Currently, many agricultural systems rely more on the use of chemical pesticides to combat plants diseases. The chemicals have several negative impacts on both human health and the environment. Therefore, there is need to investigate the ability to fight plant pathogens of alternatives like the Pseudomonas spp that do not harm the environment. Several strains of this genus are yet to be tested to see if they induce systemic resistance. Previous studies showed that bio surfactants produced by Pseudomonas koreensis exhibited strong effect against oomycetes P. ultimum in tomato plants. Induced systemic resistance (ISR) potential of P. koreensis following exposure to viruses has not been fully demonstrated to date. This study sought to investigate whether this strain has an effect on viruses and if it is able to induce systemic resistance against viral pathogens. The study started by growing the model plant N. benthamiana. The second stage involved carrying out assays of tobacco mosaic virus (TMV) after inoculating this virus in three bio treatments: (i) seed treatment of N. benthamiana with P. koreensis (referred to as the early treatment), (ii) root treatment at the transplanting stage (late treatment) and (iii) the control. In bio treatments (i) seeds were first sterilized by dipping them into 70% alcohol for 3 minutes and 0.1 % HgCl2 for 1 minute and washing them with distilled water. Each seed was then soaked into 20ml of bacteria suspension for 30 minutes and in (ii) a litre of P. koreensis culture was then poured onto the roots of 36 N. benthamiana plants. The bacteria suspension was added at 107 colony forming units per gram of soil to each tray. It was observed that disease severity was lower in the P. koreensis plant treatments than for the control. Results of this investigation have shown that P. koreensis can induce systemic resistance in foliar parts when plant seeds or roots are inoculated with this strain. This was demonstrated by separation of plant growth promoting rhizobacteria (PGPR) bacteria and TMV. Seeds and roots were inoculated with bacteria while the leaves were inoculated with TMV. The early bio treatment had the lowest mean number of necrotic lesions, and exhibited the mildest effects from TMV compared to the late bio treatment and control. Plants in the late bio treatment were moderately affected while the control was severely affected (P˂0.0001) ˂0.05. The early and the late bio treatment both had higher leaf surface area than the control; (P˂0.0001) ˂0.05. The early bio treatment lost the fewest leaves, and the late bio treatment lost a moderate number while the control lost the highest number (P˂0.0001)˂0.05.The reduced symptoms exhibited by plants inoculated with P. koreensis is an indication that P. koreensis has anti-viral activity against TMV. It was concluded that P. koreensis can reduce plant‟s viral susceptibility and result in ISR. It is hence proposed that P. koreensis can be used as a biological control (bio control) agent against viruses. Key words: Tobacco Mosaic Virus (TMV), Pseudomonas koreensis (P. koreensis), induced systemic resistance (ISR) / LG2018
9

MenzelJohannes_MSc_July_2013

2013 July 1900 (has links)
ABSTRACT The molecular mechanisms controlling longevity have been subject to intense scrutiny in recent years. It is clear that genomic stability, stress response and nutrient signaling all play critical roles in lifespan determination, but the precise molecular mechanisms and their often subtle influence on cellular function remain largely unknown. The Anaphase Promoting Complex (APC) is an evolutionarily conserved ubiquitin-protein ligase composed of 13 subunits in yeast, required for M and G1 cell cycle progression, and is associated with cancer and premature aging in many model systems when defective. The APC targets substrates for proteasome-dependent degradation, yet the full range of APC substrates and their role in mediating genomic stability, stress response and longevity are largely unknown. In this study, we use the model organism Saccharomyces cerevisiae to investigate the results of two screens designed to identify novel APC targets, regulators and/or modifiers, in an effort to better understand the function of the APC. Both of these screens made use of the Apc5 subunit. This subunit is likely an important structural component of the APC and may be targeted by many APC regulatory enzymes. This subunit is essential, but a temperature sensitive (ts) allele of Apc5 was available for these studies. First, a Yeast 2-Hybrid (Y2H) screen utilizing Apc5 as bait recovered the lifespan determinant Fob1 as a potential APC substrate. We hypothesized that the APC targets Fob1 for proteasome- and ubiquitin-dependent degradation. Authenticating Fob1 as a novel APC substrate makes up the first part of this thesis. We have found that Fob1 is unstable specifically in G1, and cycles throughout the cell cycle in a manner similar to Clb2, an APC target. Consistent with the APC mediating Fob1 degradation, Fob1 is stabilized in APC and proteasome mutants. Disruption of FOB1 in WT cells increased replicative lifespan, a measure of how many daughter cells a single mother will produce prior to senescence; moreover, FOB1 disruption improved APC mutant replicative lifespan defects. Increased FOB1 expression decreased replicative lifespan in WT cells, while increased expression in APC mutant cells did not reduce replicative lifespan further, suggesting an epistatic interaction. FOB1 deletion also suppressed cell cycle progression, and rDNA recombination defects observed in apc5CA cells. Mutation to a putative Destruction Box-like motif (Fob1E420V) disrupted Fob1 modification, stabilized the protein and increased rDNA recombination. These results support our hypothesis that Fob1 is a novel APC target and that Fob1 dosage may be regulated by the APC in response to cell cycle and environmental cues to regulate APC-dependent genomic stability and longevity. Second, an aptamer (small peptide) based screen identified peptides capable of suppressing the ts defect of the apc5CA mutant. One aptamer of interest is Y65, which has homology to the ubiquitin ligase Elc1. A Y2H found that this peptide Y65 binds the unstable stress response transcription factor Cin5. We hypothesized that this peptide may stabilize Cin5 by masking ubiquitin-dependent degradation. Stabilized Cin5 may in turn alleviate some apc5CA mutant defects. Characterizing Cin5 and confirming that Cin5 is subject to proteasome and ubiquitin-dependent degradation makes up the second portion of this thesis. During our investigation of Cin5 we identify a phospho-inhibited degradation motif within Cin5 that prevents ubiquitination and subsequent degradation when phosphorylated. We also provide evidence suggesting Cin5 may be targeted by a previously unidentified ubiquitin ligase subcomplex including Elc1 and Grr1. These data have helped elucidate the ubiquitin dependent regulation of Cin5. In summary, this research demonstrates the feasibility of using the Y2H and aptamer screens to identify and characterize molecular networks that interplay with the APC. Additionally, identifying and characterizing proteins where APC activity or function can be modified by aptamer binding has the potential to classify drug targets for therapeutic use in higher eukaryotes. Further understanding of the role the APC plays in cell cycle progression, chromatin assembly, genomic stability, stress response and longevity will be valuable to fundamental biological science, and may also have applications in health science and medicine.
10

Salt Mass Balance Study and Plant Physiological Responses for an Enhanced Salt Phytoremediation System

Zhong, Han January 2011 (has links)
Salinity is one of the most severe environmental factors that limits global crop yield. Enhanced phytoremediation using plant growth promoting rhizobacteria (PGPR) has proven to be an effective and environmentally responsible approach to remove salt from the surface soil and reclaim salt-impacted soil for crop production. PGPR enhanced phytoremediation systems (PEPS) were applied to two research sites, Cannington Manor North (CMN) and Cannington Manor South (CMS) in southern Saskatchewan. The sites were impacted by brine leakage during upstream oil and gas production. A salt mass balance study was performed based on data collected from these two sites. Both sites were planted in June. Soil samples were taken in June 2009 (beginning of the season), August (midseason) and October (end of the season). Soil salinity changes throughout the season were monitored by measuring soil electrical conductivity (EC). The average surface soil ECe decreased from 3.7 dS/m to 3.1 dS/m at CMN, and from 10.2 dS/m to 9.2 dS/m at CMS in 2009 season. Plant samples that were collected in August and October were analyzed for sodium and chloride concentrations. These values were then converted into predicted ECe changes for the soil to compare with the actual changes in soil ECe. Plant uptake of NaCl was calculated to account for 25.2% and 28.1% of the decrease in surface soil ECe at CMN and CMS, respectively. However, plant samples were washed prior to salt content analysis. A considerable amount of salt could have been lost during the washing process. Several plant samples from other salt-impacted sites in Saskatchewan and Alberta were selected to examine salt loss due to tissue washing. The salt ions lost by washing were determined to be 44.4% for Na+ and 63.8% for Cl-. After the adjustment of plant NaCl uptake data by the loss due to washing, plant accumulation of NaCl accounted for 59.9% of the decrease in surface soil ECe at CMN and 56.1% at CMS. When plant uptake of K+ and Ca2+ were also taken into consideration by a simulation study, the decrease in surface soil ECe that was caused by plant uptake of salt ions accounted for 107.5% at CMN and 117.5% at CMS. This indicated that plants can have a significant role in the remediation of salt-impacted soil. The effects of PGPR (Pseudomonas spp. UW4 and Pseudomonas corrugata CMH3) treatment on selected physiological indicators, such as proline, superoxide dismutase (SOD), membrane leakage and photosynthesis, were examined on annual ryegrass (Lolium multiflorum). Plants were grown under three saline conditions: non-saline topsoil, non-saline topsoil spiked with NaCl to 10 dS/m, and high saline soil collected from a salt-impacted site diluted with non-saline topsoil to reach 10 dS/m. The shoot fresh weight of plants grown in spiked salt soil decreased by 74% and in diluted salt soil by 44%, respectively, compared to control soil. Both types of salt soil increased SOD activities by approximately 50%, proline concentrations by 20 to 25 fold, and membrane leakage levels by 1.6 to 2.8 fold. Significant impairment of photosynthetic performances, as indicated by the decreases in the chlorophyll fluorescence parameters Fv/Fm, yield and qP, and a parallel increase in qN, was also observed using Pulse Amplitude Modulation (PAM) fluorometry for plants in diluted impacted soil. PGPR moderately increased fresh weight and SOD activity. Both UW4 and CMH3 significantly increased proline concentration and lowered membrane leakage relative to untreated plants. Therefore, PGPR improve plant performance under salt stress by elevating proline levels, which can act as a quencher of destructive reactive oxygen species. PGPR treatment also restored all the chlorophyll fluorescence parameters nearly to the non-stressed level, indicating protection of photosynthetic tissues of PGPR treated plants under salt stress. Overall, PEPS was successfully applied to the salt-impacted sites. Plant uptake of salt played a major role in the decrease of surface soil ECe. PGPR’s role in enhancing plant performance under salt stress was suggested by the elevated proline concentrations, the decreased membrane leakage levels and the restored photosynthetic activity.

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