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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.
211

The physiology of pinus patula seedlings in response to water stress and the implications for plantation regeneration in South Africa.

Rolando, Carol Ann. January 2008 (has links)
Pinus patula Schiede ex Schlect. & Cham. is the most widely planted softwood species for both pulpwood and saw timber in the South African forestry industry. High mortality of this species, often in excess of 20%, following planting is currently of major concern and has the potential to limit future deployment for commercial timber. Water stress is often reported to be a cause of mortality during regeneration in commercial forestry plantations yet, prior to 2007, there was no published research on the water relations of P. patula during regeneration in South Africa. This, together with questions raised by the industry as to the role of using water in the planting operation, initiated the series of studies conducted for this thesis. Water planting (application of water into the planting hole at the time of planting) of P. patula seedlings has been used commercially to reduce post-planting water stress and buffer against potentially extreme weather conditions immediately after planting. However, the primary role of the water, as well as its success in increasing survival following planting, has never been critically assessed. Since the use of water in the planting operation is expensive, it was essential that the benefits to using water were quantified, in terms of survival and growth, and justified, in terms of any monetary investment. In addition, there was a lack of local studies investigating the physiological characteristics of P. patula seedlings, particularly their tolerance to low soil water availability. To understand the role of water during the regeneration of P. patula in terms of plantation management and seedling physiology, a variety of research methodologies were used that included: applied field trials, multivariate methods (a retrospective investigation), pot trials and the development of a simple financial model. Four field trials were implemented to test the response in P. patula survival to water applied at planting. Two trials each were situated in the KwaZulu-Natal (KZN) Midlands and Mpumalanga Escarpment. The first trial at each site was planted in spring (October) and the second in summer (February). Watering treatments consisted of different quantities of water used in the planting operation and included 0.5 litres, 2 litres, 4 litres and no water (dry plant). Only at the spring planted trial in the KZN Midlands was survival of the dry planted seedlings significantly lower than that of the seedlings planted with water, at 90 days after planting. This may have been due to low rainfall during the week before and two weeks after planting, or the small size of the seedlings used in the trial. Application of 0.5 litres of water to the planting pit was sufficient to increase survival to a level equivalent to that where 2 or 4 litres of water was used, yet only increased soil moisture in the area immediately surrounding the seedling. This suggested that the role of the water applied during planting was increased root to soil contact. Overall, these four trials indicated that planting with water had the potential to increase survival only when soil water availability was low and rainfall sporadic. There was no effect of water applied at planting on early tree growth. While the results of the four field trials provided an indication of the effect of planting with water on subsequent survival of P. patula seedlings, there was concern that the results of the four trials may not be a true reflection of a dynamic situation. Survival in response to water applied at planting may vary from year to year and across forestry regions due to the unpredictable nature of rainfall and high air temperatures during the planting season, as well as the wide range of forestry sites across which P. patula seedlings are planted. To improve our understanding, a database of 58 trials was compiled where water and dry planting had been carried out. In this way it was possible to investigate whether the results from the four field trials were reflected in a range of previously conducted field trials implemented across time and space. The trials incorporated into the dataset were all planted to P. patula between 1990 and 2005 in the summer rainfall region of southern Africa. Data related to the climate, local weather, physiography and site management at each trial were also included. Summary statistics, linear correlation and multiple regression were used to determine if site-associated variables were related to an increase in survival in the water relative to the dry planted treatments. The analyses indicated that for all 58 trials, survival was lowest during the summer months, regardless of planting treatment. Planting with water was most likely to increase survival when used during spring, autumn and winter planting, although (as with the four applied field trials) there was no overall significant relationship between water planting and survival. Based on these results it was anticipated that an understanding of the water stress physiology of P. patula seedlings was required to explain the observed trends from a more fundamental perspective; if planting with water did not always increase survival, why not? Three pot trials were conducted to increase the understanding of the water relations of P. patula seedlings. These trials were also used to provide benchmark physiological data related to stressed (water) and unstressed seedlings. The first pot trial highlighted the importance of root plug moisture at the time of planting for increasing subsequent survival. The subsequent two pot trials were aimed at investigating the interaction between planting stock quality (as determined by measures of size) and soil water availability and the effect on survival, growth and physiology of P. patula seedlings. These results indicated that P. patula seedlings were not as sensitive to high air and soil temperatures (above 30°C) and low soil water availability (below -1.5 MPa) as previously thought. The seedlings were able to tolerate low soil water availability for several weeks and, following rewatering, were able to recover from moderate and severe water stress (a shoot water potential of below -1.5 MPa). This data supported the results from the four applied field trials and retrospective study of 58 trials, where the application of water to the seedlings at planting did not substantially increase survival. In the pot trials, stomatal conductance started to decrease when shoot water potential approached -0.8 to -0.9 MPa. Stomatal closure occurred at a shoot water potential between -1.2 MPa to -1.5 MPa. Mortality due to water stress occurred only in response to extended periods of low soil water and was associated with a shoot water potential of below -3.0 MPa. There was variability between seedlings in their potential for survival and growth. Inherently bigger seedlings had a greater capacity for new root growth following planting. New root growth, as well as a greater mass of new roots, was associated with higher shoot water potentials and higher rates of transpiration under conditions of low soil water availability. This indicated that seedling quality, as determined by size, may play a role in sensitivity to water stress. The field trials, retrospective study and pot trials indicated that the practice of planting with water was not always critical to the survival of P. patula seedlings. A simple financial model was developed to estimate whether planting with water represented a cost that could be used as a decision criterion, given certain growth parameters and management scenarios. The data projected by the model were also compared to actual research data for water versus dry planting (and the inclusion of an insecticide in the water). While these comparisons were specific to the parameters included in the model for this study, as well as the results of the research trials used in the benchmarking exercises, the model indicated that; 1) costs for planting with water were likely to be recovered only when no blanking (replacing of dead trees) was carried out, with capital invested at a low return rate (3%), 2) including an insecticide in the water increased the likelihood of cost recovery, and 3) site quality had an impact on the increase in survival required to recover planting method costs, with a greater percentage increase in survival required on lower quality sites. Lower quality sites often have a lower mean annual precipitation (associated with higher rainfall variability), or shallow soils (associated with lower soil water availability) and therefore are also likely to be sites where foresters may want to use water to reduce (drought related) mortality. The impact of site quality is thus also an important factor to include in any decisions regarding planting methods (i.e. using water) and their costs. Further investigations should be aimed at examining; 1) the interaction of root plug size (as determined by container type) and soil water availability on growth and physiology of P. patula seedlings, 2) the methods of grading seedlings within a population to select those that have a high potential for survival and growth, and 3) the effects of soil water availability on the physiology, survival and growth of P. patula cuttings, as well as other pine species and hybrids grown in South Africa, such as P. elliottii, P. elliottii x P. caribaea and P. patula x P. tecunumanii. It is likely that the proportion of forestry regions planted to these hybrids will increase in the future. / Thesis (Ph.D.)-University of KwaZulu-Natal, 2008.
212

The effect of the f-component of the pseudopotential on selected properties of 5d transition metal systems

January 2008 (has links)
Cohesive energies, bulk moduli, and equilibrium lattice constants have been calculated for the 5d transition atoms (Hf, Ta, W, Re, Os, Ir and Pt) in face–centred cubic crystal lattices. We have used the ab initio pseudopotential method for the total energy calculations within the local density approximation. Two calculations have been performed for each element, one using only the s, p and d angular momentum components and another including the s, p and d components as well as the unoccupied 5f orbital in the ionic pseudopotentials. The pseudo–wave functions and charge densities of the valence electrons have been represented by a basis of plane waves. For the 5d metals the changes in the electronic structure of the solid are small and they produce small changes in the bulk properties. / Thesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2008.
213

The effects of water depth on the development and behavior of fourth instar Aedes aegypti larvae

Audet, Alexandra M. (Alexandra Margaret) January 1996 (has links)
As water depth increased, fourth instar larvae of the mosquito Aedes aegypti required progressively more time to reach the pupal stage, more individuals died or were disabled and the resulting adults were significantly smaller. Water depth affected females more severely than males and the developmental time of larvae was affected more than adult mass. Time spent by fourth instar female larvae in the feeding zone during the first five hours predicted the time to subsequent pupation. Thereafter, mean feeding time was a determining factor of subsequent adult mass. With increasing water depth, both the prepupal resting period and mean time spent in the feeding zone per feeding bout increased, whereas behavior frequency (determined by an activity index) decreased.
214

The identification and investigation of the factors associated with rigid sewer pipe deterioration and collapse

Davies, Joel Peter January 2001 (has links)
No description available.
215

ASSOCIATIONS BETWEEN BODY MASS INDEX AND SERUM URIC ACID LEVELS IN A JAPANESE POPULATION WERE SIGNIFICANTLY MODIFIED BY LRP2 rs2544390

HAMAJIMA, NOBUYUKI, MATSUO, HIROTAKA, WAKAI, KENJI, MORITA, EMI, YIN, GUANG, KAWAI, SAYO, OKADA, RIEKO, NAITO, MARIKO, SUMA, SHINO 08 1900 (has links)
No description available.
216

Trust development in International Healthcare Services: Elekta in Spain

Arrese, Sara, Wang, Liao January 2014 (has links)
Title: Trust development: a marketing strategy in the Internationalization of Healthcare Services.The case of Elekta in Spain Level: Master Thesis in Business Administration Author: Sara Arrese and Wang Liao Supervisor: Maria Fregidou-Malama Examiner: Akmal Hyder Date: 2014-10-02 Aim: The aim of this research is to examine how trust developing affects International Healthcare Services marketing while settling down into a new country. Our study is applied to Elekta in Spain. Method: In order to carry out this research, qualitative data is used, a single case study is applied, questionnaires and semi-structured interviews were carried out to collect the needed primary data. Result and Conclusions: In the case of Elekta Spain, the trust development between suppliers and customer took place during the entire relationship. In addition, the trust level at company level and individual level were found to be the most significant leaving aside the country level as there were different opinions between customers (which did not find it a deciding factor) and Elekta. Hence, for the marketing strategy, standardization and adaptations can improve trust development. Suggestions for future research: Generalization cannot be made after this research as a single case study in one country has been the subject for investigation. Consequently, future research of other service industries and countries could expand this study. Contribution of the thesis: This thesis offers a new theoretical framework of trust development in the Spanish Healthcare Industry. This framework not only can be adapted to further study of other countries, but also can be adapted to further study of other service industries.
217

Sport psychological skills that distinguish between u/19 club rugby players of different participation levels and positional groups / Michelle Andrew.

Andrew, Michelle January 2006 (has links)
Sport psychological skills play an important role in sport performance. Evidence further suggests that the psychological skill levels may be influenced by the particular playing position. One hundred and eighty u/19 rugby players from the PUK Rugby Institute (average age: 18.79 +- 0.28 years) were tested during the 2003-2005 rugby seasons by means of the Competitive State Anxiety Inventory-2 (CSAI-2), Psychological Skills Inventory (PSI), Athletic Coping Skills Inventory-28 (ACSI-28), as well as a questionnaire dealing with psychosocial factors influencing participation and performance in rugby. Players from the 2004 and 2005 seasons (n=120) were first divided into two groups (top- and lower ranked players) of 60 players each. Effect size results (practical significance) revealed moderately significant differences between the two groups, with the top ranked players outscoring their lower ranked counterparts in self-confidence, general coping resources, coping with adversity, average psychological skills score, as well as the effect of team members/team spirit, coaches and financial aspects on participation and performance. These results confirm that sport psychological skill levels and related psychosocial factors can distinguish between rugby union players of different participation levels. Secondly, the total subject group (n=180) was divided into seven positional groups (props, hookers, locks, loose trio, half-backs, centres and back three). These groups were compared by means of effect sizes (practical significance) for each of seven sport psychological skills as measured with the PSI. Moderate (46) and large (20) practically significant differences were reported for the 147 inter-positional comparisons. The results show that the half-backs and hookers consistently outperformed the other three positional groups, while the props, locks and back three often showed the lowest skill levels. While these results are discussed in reference to practical implications for future position specific sport psychological skills training sessions, they clearly show that sport psychological skill levels differ from one position to another. / Thesis (M.Sc. (Human Movement Science))--North-West University, Potchefstroom Campus, 2006.
218

Achieving operational efficiency within the local sphere of government / Manale Daniel Tsoai

Tsoai, Manale Daniel January 2008 (has links)
The study was done within the local government environment. It was conducted with the aim of assisting municipalities to achieve optimum levels of operational efficiency, following the realisation that all over the world there is an increasing need for organisations, including government organisations, to become efficient. One of the major challenges facing governments worldwide is the need for them to supply basic services to their populations, who are increasing at a disproportionate rate to the resources available to sustain and improve the quality of life of these people. Thus for government to overcome these challenges, it needs to utilise its available resources cautiously to be able to meet these escalating challenges effectively. Therefore, ten practices were presented in this study as key instruments capable of bringing about efficiency to the manner in which local government operates or delivers services. It was found during the literature review that when these practices are deployed, they will ensure the achievement of operational efficiency within the local sphere of government. The empirical study was conducted in Matjhabeng Local Municipality (MLM), located in the Northern region of the Free State Province. This local municipality came into existence on the 5th of December 2000 after the amalgamation of the former six transitional local councils into one financially viable and economically sustainable municipality. It incorporates the city of Welkom and the towns of Virginia, Odendaalsrus, Hennenman, Allanridge and Ventersburg, with an estimated population of more than 500 000 people. During the background review of the municipality, several challenges were encountered which included parts of the population without access to proper sanitation and electricity. However, in all the municipal challenges presented, it was argued that the solution can be found in the effective management of municipal input with relation to its output, which means that the municipality has the huge task of managing its scarce resources in an efficient manner to be able to deliver on its mandate and to meet the expectations of its residents. Furthermore, the study was conducted from a sample consisting of the four senior managers and twenty line managers from the four departments within the municipality. A representative sampling method was employed to ensure that all relevant aspects (such as race, gender and department), considered important for selecting a sample, are included and to also obtain global responses from respondents selected to participate in the study. Furthermore this sample was drawn from a population of nine senior managers and 35 line managers. The research was conducted with the expressed permission from the office of the accounting officer. Different impressions of the responses made by the participants from this municipality were obtained and then analysed. Overall, there was a negative response from the majority of the participants regarding most of the questions on the ten practices identified. Moreover, in terms of the devised model for measuring efficiency of the municipality based on three levels, the most desirable being Level 3, it was found that the municipality could be classified as a Level 1 organisation, which means that the municipality is at an elementary phase as far as achieving efficiency in its operations is concerned. Lastly, recommendations were made based on the findings of the empirical research conducted. / Thesis (M.B.A.)--North-West University, Vaal Triangle Campus, 2009.
219

Achieving operational efficiency within the local sphere of government / Manale Daniel Tsoai

Tsoai, Manale Daniel January 2008 (has links)
The study was done within the local government environment. It was conducted with the aim of assisting municipalities to achieve optimum levels of operational efficiency, following the realisation that all over the world there is an increasing need for organisations, including government organisations, to become efficient. One of the major challenges facing governments worldwide is the need for them to supply basic services to their populations, who are increasing at a disproportionate rate to the resources available to sustain and improve the quality of life of these people. Thus for government to overcome these challenges, it needs to utilise its available resources cautiously to be able to meet these escalating challenges effectively. Therefore, ten practices were presented in this study as key instruments capable of bringing about efficiency to the manner in which local government operates or delivers services. It was found during the literature review that when these practices are deployed, they will ensure the achievement of operational efficiency within the local sphere of government. The empirical study was conducted in Matjhabeng Local Municipality (MLM), located in the Northern region of the Free State Province. This local municipality came into existence on the 5th of December 2000 after the amalgamation of the former six transitional local councils into one financially viable and economically sustainable municipality. It incorporates the city of Welkom and the towns of Virginia, Odendaalsrus, Hennenman, Allanridge and Ventersburg, with an estimated population of more than 500 000 people. During the background review of the municipality, several challenges were encountered which included parts of the population without access to proper sanitation and electricity. However, in all the municipal challenges presented, it was argued that the solution can be found in the effective management of municipal input with relation to its output, which means that the municipality has the huge task of managing its scarce resources in an efficient manner to be able to deliver on its mandate and to meet the expectations of its residents. Furthermore, the study was conducted from a sample consisting of the four senior managers and twenty line managers from the four departments within the municipality. A representative sampling method was employed to ensure that all relevant aspects (such as race, gender and department), considered important for selecting a sample, are included and to also obtain global responses from respondents selected to participate in the study. Furthermore this sample was drawn from a population of nine senior managers and 35 line managers. The research was conducted with the expressed permission from the office of the accounting officer. Different impressions of the responses made by the participants from this municipality were obtained and then analysed. Overall, there was a negative response from the majority of the participants regarding most of the questions on the ten practices identified. Moreover, in terms of the devised model for measuring efficiency of the municipality based on three levels, the most desirable being Level 3, it was found that the municipality could be classified as a Level 1 organisation, which means that the municipality is at an elementary phase as far as achieving efficiency in its operations is concerned. Lastly, recommendations were made based on the findings of the empirical research conducted. / Thesis (M.B.A.)--North-West University, Vaal Triangle Campus, 2009.
220

The levels of self-criticism and forms of dependency: their relation to attachment, the working alliance, and outcome

Banack, Kendell D 11 1900 (has links)
This study examined the relationships between attachment style and the levels of self-criticism (comparative and introjective) and forms of dependency (neediness and connectedness) and the working alliance and outcome variables over the course of psychotherapy. Sixty-five adult clients receiving therapy at a mental health clinic completed questionnaires after the first, fifth, and second to last sessions. Strong positive correlations were found between neediness and insecure attachment and negative correlations between neediness and secure attachment. Similar, yet weaker relationships were found between connectedness and attachment. Comparative self-criticism was positively associated with preoccupied and fearful attachment and negatively associated with secure attachment. Similar, yet weaker relationships were found between introjective self-criticism and attachment. Connectedness was associated with a strong working alliance across therapy and comparative self-criticism with a poor working alliance at session five. Although neediness was associated with poor outcome, preoccupied attachment was the best predictor of poor therapeutic outcome. / Counselling Psychology

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