Verification of Ionospheric tomography using MIDAS over Grahamstown, South Africa
- Authors: Katamzi, Zama Thobeka
- Date: 2008
- Subjects: Ionosphere -- Remote sensing -- South Africa , Atmosphere, Upper , Tomography -- Scientific applications -- South Africa , Global Positioning System
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5497 , http://hdl.handle.net/10962/d1005283 , Ionosphere -- Remote sensing -- South Africa , Atmosphere, Upper , Tomography -- Scientific applications -- South Africa , Global Positioning System
- Description: Global Positioning System (GPS) satellites and receivers are used to derive total electron content (TEC) from the time delay and phase advance of the radiowaves as they travels through the ionosphere. TEC is defined as the integralof the electron density along the satellite-receiver signal path. Electron densityprofiles can be determined from these TEC values using ionospheric tomographic inversion techniques such as Multi-Instrument Data Analysis System (MIDAS).This thesis reports on a study aimed at evaluating the suitability of ionospheric tomography as a tool to derive one-dimensional electron density profiles, using the MIDAS inversion algorithm over Grahamstown, South Africa (33.30◦S, 26.50◦E). The evaluation was done by using ionosonde data from the Louisvale (28.50◦S, 21.20◦E) and Madimbo (22.40◦S, 30.90◦E) stations to create empirical orthonormal functions (EOFs). These EOFs were used by MIDAS in the inversion process to describe the vertical variation of the electron density. Profiles derived from the MIDAS algorithm were compared with profiles obtained from the international Reference Ionosphere (IRI) 2001 model and with ionosonde profiles from the Grahamstown ionosonde station. The optimised MIDAS profiles show a good agreement with the Grahamstown ionosonde profiles. The South African Bottomside Ionospheric Model (SABIM) was used to set the limits within which MIDAS was producing accurate peak electron density (NmF2) values and to define accuracy in this project, with the understanding that the national model (SABIM) is currently the best model for the Grahamstown region. Analysis show that MIDAS produces accurate results during the winter season, which had the lowest root mean square (rms) error of 0.37×1011[e/m3] and an approximately 86% chance of producing NmF2 closer to the actual NmF2 value than the national model SABIM. MIDAS was found to also produce accurate NmF2 values at 12h00 UT, where an approximately 88% chance of producing an accurate NmF2 value, which may deviate from the measured value by 0.72×1011[e/m3], was determined. In conclusion, ionospheric tomographic inversion techniques show promise in the reconstruction of electron density profiles over South Africa, and are worth pursuing further in the future.
- Full Text:
- Date Issued: 2008
- Authors: Katamzi, Zama Thobeka
- Date: 2008
- Subjects: Ionosphere -- Remote sensing -- South Africa , Atmosphere, Upper , Tomography -- Scientific applications -- South Africa , Global Positioning System
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5497 , http://hdl.handle.net/10962/d1005283 , Ionosphere -- Remote sensing -- South Africa , Atmosphere, Upper , Tomography -- Scientific applications -- South Africa , Global Positioning System
- Description: Global Positioning System (GPS) satellites and receivers are used to derive total electron content (TEC) from the time delay and phase advance of the radiowaves as they travels through the ionosphere. TEC is defined as the integralof the electron density along the satellite-receiver signal path. Electron densityprofiles can be determined from these TEC values using ionospheric tomographic inversion techniques such as Multi-Instrument Data Analysis System (MIDAS).This thesis reports on a study aimed at evaluating the suitability of ionospheric tomography as a tool to derive one-dimensional electron density profiles, using the MIDAS inversion algorithm over Grahamstown, South Africa (33.30◦S, 26.50◦E). The evaluation was done by using ionosonde data from the Louisvale (28.50◦S, 21.20◦E) and Madimbo (22.40◦S, 30.90◦E) stations to create empirical orthonormal functions (EOFs). These EOFs were used by MIDAS in the inversion process to describe the vertical variation of the electron density. Profiles derived from the MIDAS algorithm were compared with profiles obtained from the international Reference Ionosphere (IRI) 2001 model and with ionosonde profiles from the Grahamstown ionosonde station. The optimised MIDAS profiles show a good agreement with the Grahamstown ionosonde profiles. The South African Bottomside Ionospheric Model (SABIM) was used to set the limits within which MIDAS was producing accurate peak electron density (NmF2) values and to define accuracy in this project, with the understanding that the national model (SABIM) is currently the best model for the Grahamstown region. Analysis show that MIDAS produces accurate results during the winter season, which had the lowest root mean square (rms) error of 0.37×1011[e/m3] and an approximately 86% chance of producing NmF2 closer to the actual NmF2 value than the national model SABIM. MIDAS was found to also produce accurate NmF2 values at 12h00 UT, where an approximately 88% chance of producing an accurate NmF2 value, which may deviate from the measured value by 0.72×1011[e/m3], was determined. In conclusion, ionospheric tomographic inversion techniques show promise in the reconstruction of electron density profiles over South Africa, and are worth pursuing further in the future.
- Full Text:
- Date Issued: 2008
Water quality, abalone growth and the potential for integrated mariculture on a South African abalone Haliotis midae L. farm
- Authors: Yearsley, Rowan David
- Date: 2008
- Subjects: Abalones -- South Africa Abalone culture -- South Africa Abalones -- Growth Mariculture -- South Africa Water quality -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5334 , http://hdl.handle.net/10962/d1005180
- Description: Abalone Haliotis midae farming in South Africa is highly intensive, employing pump-ashore, flow-through systems. Despite the known sensitivity of abalone to water quality, there is only a rudimentary understanding of water quality dynamics on South African abalone farms and its effects on abalone production. Furthermore, the potential for reusing the relatively dilute abalone farm effluent to culture other animal species has not been investigated. This study investigated the dynamics of water quality and growth on a South African abalone farm and assessed the suitability of the effluent for the culture of silver kob Argyrosomus inodorus and bloodworm Arenicola loveni loveni. Monitoring of water quality and abalone growth in abalone tanks revealed that oxygen concentrations decreased, while H⁺ ion and free-ammonia (NH₃) concentration increased in a gradient between the inflow and outflow. Abalone growth was positively correlated with oxygen concentration and negatively correlated with free-ammonia and H⁺ ion concentration. The oxygen (O) concentration of the farm influent was dependent upon the influents’ temperature (T) and was described by the relationship O (mg L⁻¹) = 11.244 – 0.208T (r²=0.74). Linear regression analysis of data collected from abalone farm tanks revealed that the concentration of total ammonia at the outflow of abalone tanks (μg TAN L⁻¹) was dependant upon temperature (°C), flow-rate (L s⁻¹ kg⁻¹ H. midae), abalone size (g) and length of time since the tank was last cleaned (d) (n = 125, r² = 0.80). The production of total ammonia (μg TAN s⁻¹ kg⁻¹) was related to temperature, abalone size and days that the tanks remained un-cleaned (n = 125; r² = 0.81). A diurnal cycle of respiration was evident in abalone tanks with higher oxygen consumption and H+ ion production at night. The oxygen concentration of farm effluent was related to temperature, farm biomass and flow rate by means of a linear regression equation (n = 40; r² = 0.69). The results demonstrated the importance of optimising the flow-rate per unit of biomass for various temperatures and sizes of abalone. As abalone size and temperature cannot be controlled under farm conditions, the flow-rate per unit of biomass which the abalone culture system receives will determine the quality of the culture water. The specific growth rate (0.48 ± 0.01 % BW d⁻¹), mortality (1.8 ± 0.5 %), feed conversion ratio (3.0 ± 0.2) and protein efficiency ratio (1.0 ± 0.1) of silver kob kept in either abalone farm effluent or control seawater for 120 days did not differ significantly (t-test, P>0.05). A 90 day growth trial indicated that abalone farm effluent is a suitable culture medium for bloodworm. Bloodworm supplied with control seawater lost weight at 0.19 ± 0.04 % BW d-1, while those given abalone effluent grew at 0.39 ± 0.07 % BW d⁻¹. Mortality was 6 ± 3 % in effluent and 11 ± 8 % in seawater. The bloodworm were efficient at processing solid waste. Abalone farm effluent initially contained 7.7 ± 13 mg L⁻¹ more suspended solids than control seawater, which contained 3.5 ± 0.5 mg L⁻¹, but after passing through bloodworm systems the concentration in abalone effluent was reduced to only 1.4 ± 3.5 mg L⁻¹ above that in control seawater. Therefore, abalone farm effluent could be reused as a culture medium for both silver kob and bloodworm. Future work is needed to investigate aspects of the feasibility of such systems such as growth rates at different sizes and stocking densities.
- Full Text:
- Date Issued: 2008
- Authors: Yearsley, Rowan David
- Date: 2008
- Subjects: Abalones -- South Africa Abalone culture -- South Africa Abalones -- Growth Mariculture -- South Africa Water quality -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5334 , http://hdl.handle.net/10962/d1005180
- Description: Abalone Haliotis midae farming in South Africa is highly intensive, employing pump-ashore, flow-through systems. Despite the known sensitivity of abalone to water quality, there is only a rudimentary understanding of water quality dynamics on South African abalone farms and its effects on abalone production. Furthermore, the potential for reusing the relatively dilute abalone farm effluent to culture other animal species has not been investigated. This study investigated the dynamics of water quality and growth on a South African abalone farm and assessed the suitability of the effluent for the culture of silver kob Argyrosomus inodorus and bloodworm Arenicola loveni loveni. Monitoring of water quality and abalone growth in abalone tanks revealed that oxygen concentrations decreased, while H⁺ ion and free-ammonia (NH₃) concentration increased in a gradient between the inflow and outflow. Abalone growth was positively correlated with oxygen concentration and negatively correlated with free-ammonia and H⁺ ion concentration. The oxygen (O) concentration of the farm influent was dependent upon the influents’ temperature (T) and was described by the relationship O (mg L⁻¹) = 11.244 – 0.208T (r²=0.74). Linear regression analysis of data collected from abalone farm tanks revealed that the concentration of total ammonia at the outflow of abalone tanks (μg TAN L⁻¹) was dependant upon temperature (°C), flow-rate (L s⁻¹ kg⁻¹ H. midae), abalone size (g) and length of time since the tank was last cleaned (d) (n = 125, r² = 0.80). The production of total ammonia (μg TAN s⁻¹ kg⁻¹) was related to temperature, abalone size and days that the tanks remained un-cleaned (n = 125; r² = 0.81). A diurnal cycle of respiration was evident in abalone tanks with higher oxygen consumption and H+ ion production at night. The oxygen concentration of farm effluent was related to temperature, farm biomass and flow rate by means of a linear regression equation (n = 40; r² = 0.69). The results demonstrated the importance of optimising the flow-rate per unit of biomass for various temperatures and sizes of abalone. As abalone size and temperature cannot be controlled under farm conditions, the flow-rate per unit of biomass which the abalone culture system receives will determine the quality of the culture water. The specific growth rate (0.48 ± 0.01 % BW d⁻¹), mortality (1.8 ± 0.5 %), feed conversion ratio (3.0 ± 0.2) and protein efficiency ratio (1.0 ± 0.1) of silver kob kept in either abalone farm effluent or control seawater for 120 days did not differ significantly (t-test, P>0.05). A 90 day growth trial indicated that abalone farm effluent is a suitable culture medium for bloodworm. Bloodworm supplied with control seawater lost weight at 0.19 ± 0.04 % BW d-1, while those given abalone effluent grew at 0.39 ± 0.07 % BW d⁻¹. Mortality was 6 ± 3 % in effluent and 11 ± 8 % in seawater. The bloodworm were efficient at processing solid waste. Abalone farm effluent initially contained 7.7 ± 13 mg L⁻¹ more suspended solids than control seawater, which contained 3.5 ± 0.5 mg L⁻¹, but after passing through bloodworm systems the concentration in abalone effluent was reduced to only 1.4 ± 3.5 mg L⁻¹ above that in control seawater. Therefore, abalone farm effluent could be reused as a culture medium for both silver kob and bloodworm. Future work is needed to investigate aspects of the feasibility of such systems such as growth rates at different sizes and stocking densities.
- Full Text:
- Date Issued: 2008
Water, salt and nutrient budgets of the Swartkops and Sundays river estuaries using the loicz biogeochemical budgeting protocol
- Authors: Potgieter, Matthys Johannes
- Date: 2008
- Subjects: Estuarine oceanography , Groundwater flow -- South Africa -- Swartkops River Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10705 , http://hdl.handle.net/10948/903 , Estuarine oceanography , Groundwater flow -- South Africa -- Swartkops River Estuary
- Description: The Swartkops River and Sundays River Estuaries are different in terms of morphology and the level of human impact. Budget models of DIP and DIN were constructed for each estuary at different riverine flow rates, using the Land-Ocean Interactions in the Coastal Zone (LOICZ) protocol. Nutrient dynamics in the estuaries were investigated using nutrient data and the results of the models. The Swartkops River Estuary acted as a sink of DIP and DIN, while being net heterotrophic. The Sundays River Estuary acted as a source of DIP and DIN, while being net autotrophic. Both systems were net denitrifying. The Swartkops River Estuary shows greater anthropogenic impacts in terms of nutrient loads than the Sundays River Estuary. A shift in nutrient concentration trends and system properties occurred between conditions of low and high riverine flow rates. The Swartkops River and Sundays River Estuaries were shown to be ‘outwellers’ of DIN and DIP, while having an important influence on the ratio of DIN:DIP exported to the adjacent ocean. Comparisons with other estuaries suggested that riverine flow into estuaries in the Eastern Cape region may display natural DIN:DIP ratios which are lower than the global average for “pristine” systems. Such ratios would be decreased further by increased water extraction for human activities.
- Full Text:
- Date Issued: 2008
- Authors: Potgieter, Matthys Johannes
- Date: 2008
- Subjects: Estuarine oceanography , Groundwater flow -- South Africa -- Swartkops River Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10705 , http://hdl.handle.net/10948/903 , Estuarine oceanography , Groundwater flow -- South Africa -- Swartkops River Estuary
- Description: The Swartkops River and Sundays River Estuaries are different in terms of morphology and the level of human impact. Budget models of DIP and DIN were constructed for each estuary at different riverine flow rates, using the Land-Ocean Interactions in the Coastal Zone (LOICZ) protocol. Nutrient dynamics in the estuaries were investigated using nutrient data and the results of the models. The Swartkops River Estuary acted as a sink of DIP and DIN, while being net heterotrophic. The Sundays River Estuary acted as a source of DIP and DIN, while being net autotrophic. Both systems were net denitrifying. The Swartkops River Estuary shows greater anthropogenic impacts in terms of nutrient loads than the Sundays River Estuary. A shift in nutrient concentration trends and system properties occurred between conditions of low and high riverine flow rates. The Swartkops River and Sundays River Estuaries were shown to be ‘outwellers’ of DIN and DIP, while having an important influence on the ratio of DIN:DIP exported to the adjacent ocean. Comparisons with other estuaries suggested that riverine flow into estuaries in the Eastern Cape region may display natural DIN:DIP ratios which are lower than the global average for “pristine” systems. Such ratios would be decreased further by increased water extraction for human activities.
- Full Text:
- Date Issued: 2008
Whole body vibration training and physical fitness of persons with diabetes melitus type II
- Authors: Bekker, Lindy
- Date: 2008
- Subjects: Diabetes -- Exercise therapy , Vibration -- Physiological effect
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10096 , http://hdl.handle.net/10948/672 , Diabetes -- Exercise therapy , Vibration -- Physiological effect
- Description: The aim of this study was to determine the effect of whole body vibration training on selected health and fitness parameters, including: blood glucose levels, blood pressure, anthropometric profile, muscular flexibility, muscular strength, muscular endurance, and aerobic endurance of persons with diabetes mellitus type II. The study was conducted in a descriptive, explorative manner utilizing a quasiexperimental design with an equistatic approach, employing match-pair design to participant grouping. The experimental design was a non-randomized two-group pre- and post-test design, in which approximately 16 male and female participants, who were chosen through convenience and snowball sampling with diabetes mellitus type II, completed the study. Pre- and post-test analysis was performed at the Biokinetics and Sport Science Unit. The whole body vibration training (experimental) group, trained three times a week for a period of ten weeks, performing exercises on the vibration platform with progressive increments in the intensity, duration, and number of the exercises. The control group remained sedentary throughout the intervention period. The dependant variables were analyzed using descriptive statistics. ANOVA was done to determine pre- and post-test differences for both the experimental and control groups for all the variables. Post-Hoc analysis was done to determine and compare differences which may have existed between the experimental and control groups, with practical significance being determined by Cohen’s D analysis. The analysis of the results revealed significant improvements in systolic blood pressure, muscular strength, muscular endurance, and aerobic endurance.
- Full Text:
- Date Issued: 2008
- Authors: Bekker, Lindy
- Date: 2008
- Subjects: Diabetes -- Exercise therapy , Vibration -- Physiological effect
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10096 , http://hdl.handle.net/10948/672 , Diabetes -- Exercise therapy , Vibration -- Physiological effect
- Description: The aim of this study was to determine the effect of whole body vibration training on selected health and fitness parameters, including: blood glucose levels, blood pressure, anthropometric profile, muscular flexibility, muscular strength, muscular endurance, and aerobic endurance of persons with diabetes mellitus type II. The study was conducted in a descriptive, explorative manner utilizing a quasiexperimental design with an equistatic approach, employing match-pair design to participant grouping. The experimental design was a non-randomized two-group pre- and post-test design, in which approximately 16 male and female participants, who were chosen through convenience and snowball sampling with diabetes mellitus type II, completed the study. Pre- and post-test analysis was performed at the Biokinetics and Sport Science Unit. The whole body vibration training (experimental) group, trained three times a week for a period of ten weeks, performing exercises on the vibration platform with progressive increments in the intensity, duration, and number of the exercises. The control group remained sedentary throughout the intervention period. The dependant variables were analyzed using descriptive statistics. ANOVA was done to determine pre- and post-test differences for both the experimental and control groups for all the variables. Post-Hoc analysis was done to determine and compare differences which may have existed between the experimental and control groups, with practical significance being determined by Cohen’s D analysis. The analysis of the results revealed significant improvements in systolic blood pressure, muscular strength, muscular endurance, and aerobic endurance.
- Full Text:
- Date Issued: 2008
Whole body vibration training effects on asthma specific pulmonary variables
- Authors: Mansell, Ingrid Joan
- Date: 2008
- Subjects: Vibration -- Physiological effect , Asthma -- Exercise therapy , Asthma -- Treatment
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10112 , http://hdl.handle.net/10948/d1020953
- Description: The aim of the study was to determine and document evidence of the comparative effect of a 12- week whole body vibration training programme, exercise training programme and sedentary control group on the anthropometric profile, aerobic capacity, lung volumes and hence, the pulmonary capacity in people with asthma. The study used a descriptive, exploratory, quasi-experimental research approach employing randomised pairing to classify participants into either the whole body vibration therapy or exercise training group. Accidental and snowball sampling was used to identify and obtain a base of volunteers. A three-group pre-test/post-test design was employed to gain insight into statistical differences that might be apparent between the whole body vibration therapy group, the exercise group and the control group, and which could potentially be attributed to participation in the whole body vibration exercise programme. Randomised pairing for participant selection was selected because of the potential effects varying pulmonary variables might have had on the reliability of the study. A Physical Activity Selection Criteria Questionnaire was completed by participants to ascertain baseline physical activity readiness and as a means of determining selection criteria for their allocation to the whole body vibration training group, the experimental exercise group or the true control group. The pre-test/post-test assessment made use of a combination evaluation that incorporated an anthropometric profile assessment of height, weight, biceps, triceps, subscapular and suprailliac skinfolds, waist and hip circumference and posture, an aerobic capacity evaluation that incorporated aspects of both the YMCA and Astrand and Rhyming Physical Work Capacity (PWC) evaluation on a cycle ergometer and, lastly, a pulmonary variable assessment that made use of both the Datospir Peak-10 peak flow meter and the Spirovit SP-100AT spirometry unit integrated into the Cardiovit AT-6 model for all spirometry measurements. Participants were required to complete either the whole-body vibration or the exercise training programme a minimum of twice a week and a maximum of four times over the same period. The duration of the intervention programmes was approximately 30 minutes and consisted of three sections including a warm-up comprising flexibility exercises, whole body strength training exercises, and a cool-down which, in turn, consisted of massage exercises or replicated flexibility exercises. The main difference between the whole body vibration and exercise training group thus lay in the exclusion of the use of vibration for those participants assigned to the exercise training programme. Analysis of data was performed using descriptive and inferential statistics with the help of a qualified statistician. The identified variables were tested at a 95 percent level of probability (p<0.05) as recommended by Thomas and Nelson (1996:117). Descriptive data, in the form of a statistical mean, standard deviation, minimum, median and maximum values, obtained during this study were reported in the form of a t-score for selected anthropometric and pulmonary variables. The 12-week intervention programme, on analysis of the results, produced statistically insignificant improvements in the variables of anthropometric profile, aerobic capacity and lung volumes identified as determinants of, and factors influencing, the cardiorespiratory fitness level of participants with asthma and hence, the subsequent severity of this chronic condition. However, slight mean increases for the whole body vibration training group were evident for certain variables identified in this study. Based on the results, the inference could be made that whole body vibration therapy and exercise were both effective modes of training to improve the cardiorespiratory fitness level of people with asthma, but the results of the study did not show sufficient practical or statistical significance to verify the assumption that whole body vibration training was a method superior to conventional exercise training. Hence, the significance of whole body vibration training on the pulmonary variables of people with asthma could not be determined. The researcher recommends that future studies be undertaken to verify whether whole body vibration training incorporating larger participant groups could produce significant improvements in pulmonary variables in people with asthma.
- Full Text:
- Date Issued: 2008
- Authors: Mansell, Ingrid Joan
- Date: 2008
- Subjects: Vibration -- Physiological effect , Asthma -- Exercise therapy , Asthma -- Treatment
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10112 , http://hdl.handle.net/10948/d1020953
- Description: The aim of the study was to determine and document evidence of the comparative effect of a 12- week whole body vibration training programme, exercise training programme and sedentary control group on the anthropometric profile, aerobic capacity, lung volumes and hence, the pulmonary capacity in people with asthma. The study used a descriptive, exploratory, quasi-experimental research approach employing randomised pairing to classify participants into either the whole body vibration therapy or exercise training group. Accidental and snowball sampling was used to identify and obtain a base of volunteers. A three-group pre-test/post-test design was employed to gain insight into statistical differences that might be apparent between the whole body vibration therapy group, the exercise group and the control group, and which could potentially be attributed to participation in the whole body vibration exercise programme. Randomised pairing for participant selection was selected because of the potential effects varying pulmonary variables might have had on the reliability of the study. A Physical Activity Selection Criteria Questionnaire was completed by participants to ascertain baseline physical activity readiness and as a means of determining selection criteria for their allocation to the whole body vibration training group, the experimental exercise group or the true control group. The pre-test/post-test assessment made use of a combination evaluation that incorporated an anthropometric profile assessment of height, weight, biceps, triceps, subscapular and suprailliac skinfolds, waist and hip circumference and posture, an aerobic capacity evaluation that incorporated aspects of both the YMCA and Astrand and Rhyming Physical Work Capacity (PWC) evaluation on a cycle ergometer and, lastly, a pulmonary variable assessment that made use of both the Datospir Peak-10 peak flow meter and the Spirovit SP-100AT spirometry unit integrated into the Cardiovit AT-6 model for all spirometry measurements. Participants were required to complete either the whole-body vibration or the exercise training programme a minimum of twice a week and a maximum of four times over the same period. The duration of the intervention programmes was approximately 30 minutes and consisted of three sections including a warm-up comprising flexibility exercises, whole body strength training exercises, and a cool-down which, in turn, consisted of massage exercises or replicated flexibility exercises. The main difference between the whole body vibration and exercise training group thus lay in the exclusion of the use of vibration for those participants assigned to the exercise training programme. Analysis of data was performed using descriptive and inferential statistics with the help of a qualified statistician. The identified variables were tested at a 95 percent level of probability (p<0.05) as recommended by Thomas and Nelson (1996:117). Descriptive data, in the form of a statistical mean, standard deviation, minimum, median and maximum values, obtained during this study were reported in the form of a t-score for selected anthropometric and pulmonary variables. The 12-week intervention programme, on analysis of the results, produced statistically insignificant improvements in the variables of anthropometric profile, aerobic capacity and lung volumes identified as determinants of, and factors influencing, the cardiorespiratory fitness level of participants with asthma and hence, the subsequent severity of this chronic condition. However, slight mean increases for the whole body vibration training group were evident for certain variables identified in this study. Based on the results, the inference could be made that whole body vibration therapy and exercise were both effective modes of training to improve the cardiorespiratory fitness level of people with asthma, but the results of the study did not show sufficient practical or statistical significance to verify the assumption that whole body vibration training was a method superior to conventional exercise training. Hence, the significance of whole body vibration training on the pulmonary variables of people with asthma could not be determined. The researcher recommends that future studies be undertaken to verify whether whole body vibration training incorporating larger participant groups could produce significant improvements in pulmonary variables in people with asthma.
- Full Text:
- Date Issued: 2008
Widowhood and property inheritance in Zimbabwe: experiences of widows in Sikalenge ward, Binga District
- Authors: Dube, Misheck
- Date: 2008
- Subjects: Widows -- Legal status, laws, etc. -- Zimbabwe , Women -- Legal status, laws, etc. -- Zimbabwe , Inheritance and succession -- Zimbabwe
- Language: English
- Type: Thesis , Masters , M SW
- Identifier: vital:11755 , http://hdl.handle.net/10353/200 , Widows -- Legal status, laws, etc. -- Zimbabwe , Women -- Legal status, laws, etc. -- Zimbabwe , Inheritance and succession -- Zimbabwe
- Description: Zimbabwean widows need to inherit property when their husbands die. Property, be it material or financial in nature, is a source of sustenance and wealth. Depriving women of property inheritance rights has untold consequences. This study focuses on the property inheritance rights of widows in Zimbabwe in the Sikalenge Ward of Binga District. The aim of the study is to understand how property grabbing affects widows and to find possible solutions and intervention strategies social workers may use. The literature reviewed in the study was drawn from both the legal field and social work to create a link between the fields. The study was shaped by radical feminism for conceptualising property grabbing while the formulated intervention strategies utilised the empowerment model. The study is qualitative in nature using interviews to collect data from ten widows and five social service providers who constitute the total of fifteen participants in the study. Data was analysed qualitatively using interpretive approaches and presentation is textual rather than statistical. The main finding of the study is that widows are still being denied their inheritance rights despite the provision of such rights by the Intestate Succession Laws promulgated in November 1997 by the government of Zimbabwe. Moreover, the widows are not aware of the inheritance laws of Zimbabwe and hence did not seek any professional intervention. The few who attempted the legal process for recourse were not successful. Even though it was minimally attempted, the study established that the main form of failed intervention tried by the women was legal in nature and suggests and emphasises an eminent need for Social Work intervention to supplement legal intervention.
- Full Text:
- Date Issued: 2008
- Authors: Dube, Misheck
- Date: 2008
- Subjects: Widows -- Legal status, laws, etc. -- Zimbabwe , Women -- Legal status, laws, etc. -- Zimbabwe , Inheritance and succession -- Zimbabwe
- Language: English
- Type: Thesis , Masters , M SW
- Identifier: vital:11755 , http://hdl.handle.net/10353/200 , Widows -- Legal status, laws, etc. -- Zimbabwe , Women -- Legal status, laws, etc. -- Zimbabwe , Inheritance and succession -- Zimbabwe
- Description: Zimbabwean widows need to inherit property when their husbands die. Property, be it material or financial in nature, is a source of sustenance and wealth. Depriving women of property inheritance rights has untold consequences. This study focuses on the property inheritance rights of widows in Zimbabwe in the Sikalenge Ward of Binga District. The aim of the study is to understand how property grabbing affects widows and to find possible solutions and intervention strategies social workers may use. The literature reviewed in the study was drawn from both the legal field and social work to create a link between the fields. The study was shaped by radical feminism for conceptualising property grabbing while the formulated intervention strategies utilised the empowerment model. The study is qualitative in nature using interviews to collect data from ten widows and five social service providers who constitute the total of fifteen participants in the study. Data was analysed qualitatively using interpretive approaches and presentation is textual rather than statistical. The main finding of the study is that widows are still being denied their inheritance rights despite the provision of such rights by the Intestate Succession Laws promulgated in November 1997 by the government of Zimbabwe. Moreover, the widows are not aware of the inheritance laws of Zimbabwe and hence did not seek any professional intervention. The few who attempted the legal process for recourse were not successful. Even though it was minimally attempted, the study established that the main form of failed intervention tried by the women was legal in nature and suggests and emphasises an eminent need for Social Work intervention to supplement legal intervention.
- Full Text:
- Date Issued: 2008
Willingness to pay for the control of water hyacinth in an urban environment of South Africa
- Authors: Law, Matthew Charles
- Date: 2008
- Subjects: Water hyacinth -- Control -- South Africa , Urban ecology (Sociology) -- South Africa , Biodiversity -- Economic aspects -- South Africa , Biodiversity conservation -- Economic aspects -- South Africa , Biological invasions -- Economic aspects -- South Africa , Biological invasions -- Environmental aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:996 , http://hdl.handle.net/10962/d1002731 , Water hyacinth -- Control -- South Africa , Urban ecology (Sociology) -- South Africa , Biodiversity -- Economic aspects -- South Africa , Biodiversity conservation -- Economic aspects -- South Africa , Biological invasions -- Economic aspects -- South Africa , Biological invasions -- Environmental aspects -- South Africa
- Description: Water hyacinth is recognised as one of the most problematic invasive aquatic plant species in Africa. For this reason considerable funds are spent each year on itscontrol. As a consequence of the amount of money being spent on problems such as the invasion of water hyacinth, and because of the recognition of the ongoing and accelerated efforts that are required in the future, recent research has focused on accurately quantifying the costs and benefits of control of invasive species to aid policy decisions.A comprehensive cost-benefit analysis would be able to identify if the funds are justified and are being spent effectively. This thesis provides an example of a cost-benefit analysis of funds spent on the control of water hyacinth in an urban environment in South Africa. In order to develop a comprehensive assessment of the total economic value of the control of water hyacinth to an urban population, the Nahoon River in East London was selected as the study site to calculate the benefits of control. In addition to valuing the direct services provided by the resources that are traded in the market (in this case water provision), a contingent valuation study was undertaken in Abbottsford and Dorchester Heights (two suburbs in East London banking the Nahoon River). These were done in order to assess any non-use value a sample of 132 households of the population has for the control of water hyacinth, and any use values that are not traded in the market, for example recreational value. When the benefits of control of water hyacinth were compared to the costs of one of the least cost effective methods of control (herbicidal control), the benefits outweighed the costs by a ratio of more than 4:1, and for the most cost effective method of control the ratio was almost 6:1. These results provide a justification for the funds that are devoted to the control of water hyacinth, providing an argument for the continued expenditure for its control, and for further research into more cost effective methods of control, such as biological control.
- Full Text:
- Date Issued: 2008
- Authors: Law, Matthew Charles
- Date: 2008
- Subjects: Water hyacinth -- Control -- South Africa , Urban ecology (Sociology) -- South Africa , Biodiversity -- Economic aspects -- South Africa , Biodiversity conservation -- Economic aspects -- South Africa , Biological invasions -- Economic aspects -- South Africa , Biological invasions -- Environmental aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:996 , http://hdl.handle.net/10962/d1002731 , Water hyacinth -- Control -- South Africa , Urban ecology (Sociology) -- South Africa , Biodiversity -- Economic aspects -- South Africa , Biodiversity conservation -- Economic aspects -- South Africa , Biological invasions -- Economic aspects -- South Africa , Biological invasions -- Environmental aspects -- South Africa
- Description: Water hyacinth is recognised as one of the most problematic invasive aquatic plant species in Africa. For this reason considerable funds are spent each year on itscontrol. As a consequence of the amount of money being spent on problems such as the invasion of water hyacinth, and because of the recognition of the ongoing and accelerated efforts that are required in the future, recent research has focused on accurately quantifying the costs and benefits of control of invasive species to aid policy decisions.A comprehensive cost-benefit analysis would be able to identify if the funds are justified and are being spent effectively. This thesis provides an example of a cost-benefit analysis of funds spent on the control of water hyacinth in an urban environment in South Africa. In order to develop a comprehensive assessment of the total economic value of the control of water hyacinth to an urban population, the Nahoon River in East London was selected as the study site to calculate the benefits of control. In addition to valuing the direct services provided by the resources that are traded in the market (in this case water provision), a contingent valuation study was undertaken in Abbottsford and Dorchester Heights (two suburbs in East London banking the Nahoon River). These were done in order to assess any non-use value a sample of 132 households of the population has for the control of water hyacinth, and any use values that are not traded in the market, for example recreational value. When the benefits of control of water hyacinth were compared to the costs of one of the least cost effective methods of control (herbicidal control), the benefits outweighed the costs by a ratio of more than 4:1, and for the most cost effective method of control the ratio was almost 6:1. These results provide a justification for the funds that are devoted to the control of water hyacinth, providing an argument for the continued expenditure for its control, and for further research into more cost effective methods of control, such as biological control.
- Full Text:
- Date Issued: 2008
WISC-IV performance of South African grade 7 English and Xhosa speaking children with advantaged versus disadvantaged education
- Authors: Van Tonder, Phia
- Date: 2008
- Subjects: Wechsler Intelligence Scale for Children Intelligence tests -- South Africa Educational tests and measurements -- South Africa Psychological tests -- Cross-cultural studies Educational psychology -- South Africa Language and languages -- Ability testing Educational evaluation -- South Africa Education, Elementary -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3098 , http://hdl.handle.net/10962/d1003920
- Description: Research reveals that the level as well as the quality of education plays a role in the determination of an individual's intellectual capacity. Substantial differences in quality of education for black and white individuals were experienced in South Africa due to Apartheid. Compared to the traditionally white Private and Model C schools, Township/ DET schools had limited resources, as well as a separate syllabus and examination system, a situation that has not improved substantially since democratisation in 1994. Research on black South African adults with the WAIS-III has confirmed significant influences on IQ in association with exposure to either such advantaged (Private/Model C) schooling, or disadvantaged (Township/DET) schooling. However to date there has been no published research on the use of the Wechsler intelligence tests on a black South African child population similarly stratified for quality of education. Therefore, for the purposes of this study, the latest Wechsler Intelligence Scale for Children (WISC-IV) was administered to a sample of 36 Grade 7 learners between the ages of 12-13 (mean 13.01 years), stratified for quality of education to form three comparative groups. Data analyses revealed significant differences on the WISC-IV Factor Indices and Full Scale IQ with the English speaking Private/Model C school group performing the best, followed by the Xhosa speaking Private/ Model C school group, and the Xhosa speaking Township/ DET school group performing the worst. This continuum of lowering is understood to occur abreast of a continuum of decreased exposure to relatively advantaged education. These normative indications are considered to have vital implications for the use of the WISC-IV in the South African cross-cultural situation where vastly differential educational opportunities continue to exist.
- Full Text:
- Date Issued: 2008
- Authors: Van Tonder, Phia
- Date: 2008
- Subjects: Wechsler Intelligence Scale for Children Intelligence tests -- South Africa Educational tests and measurements -- South Africa Psychological tests -- Cross-cultural studies Educational psychology -- South Africa Language and languages -- Ability testing Educational evaluation -- South Africa Education, Elementary -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3098 , http://hdl.handle.net/10962/d1003920
- Description: Research reveals that the level as well as the quality of education plays a role in the determination of an individual's intellectual capacity. Substantial differences in quality of education for black and white individuals were experienced in South Africa due to Apartheid. Compared to the traditionally white Private and Model C schools, Township/ DET schools had limited resources, as well as a separate syllabus and examination system, a situation that has not improved substantially since democratisation in 1994. Research on black South African adults with the WAIS-III has confirmed significant influences on IQ in association with exposure to either such advantaged (Private/Model C) schooling, or disadvantaged (Township/DET) schooling. However to date there has been no published research on the use of the Wechsler intelligence tests on a black South African child population similarly stratified for quality of education. Therefore, for the purposes of this study, the latest Wechsler Intelligence Scale for Children (WISC-IV) was administered to a sample of 36 Grade 7 learners between the ages of 12-13 (mean 13.01 years), stratified for quality of education to form three comparative groups. Data analyses revealed significant differences on the WISC-IV Factor Indices and Full Scale IQ with the English speaking Private/Model C school group performing the best, followed by the Xhosa speaking Private/ Model C school group, and the Xhosa speaking Township/ DET school group performing the worst. This continuum of lowering is understood to occur abreast of a continuum of decreased exposure to relatively advantaged education. These normative indications are considered to have vital implications for the use of the WISC-IV in the South African cross-cultural situation where vastly differential educational opportunities continue to exist.
- Full Text:
- Date Issued: 2008
Within- and between-beach variation in intertidal macrofaunal communities inhabiting two Transkei sandy beaches
- Authors: Dreyer, Nicolaas Burger
- Date: 2008
- Subjects: Intertidal animals -- Ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10700 , http://hdl.handle.net/10948/1070 , Intertidal animals -- Ecology -- South Africa
- Description: Until recently most sandy beach studies have made use of snapshot samples but the validity of this approach has been widely questioned. In this study we attempt to resolve this issue by repeatedly sampling two beaches using a stratified random design. Three sampling sessions took place, each approximately six months apart. The three sites on the first beach were selected according to the type of beach (reflective, intermediate and dissipative) with each morphological type duplicated on the second beach. Many of the physical variables measured had significant differences between the sampling sessions but only a few were significantly different between the Sites. Very few of the individual physical variables had significant relationships with the sandy beach macrofaunal abundance and density. However, composite indices had a greater number of significant relationships with the macrofaunal abundance and density. Also very few significant relationships were seen between the species richness and the physical variables of the beaches studied. Effluent line crossing frequency was the only physical variable that could predict species richness but it was considered a weak predictor. Changes in the zonation patterns within and between beaches were also investigated. The highest concentration of taxa and individuals was found near the low-water mark with a gradual reduction of both towards the high-water mark. Some of the sandy beach community variables (abundance, density and species richness) showed significant difference between the sampling sessions but no significant differences were seen between the two beaches. The presence of three zones was noted using MDS plots and Cluster diagrams. However, using a SIMPER analyses, four zones with the possibility of a fifth was noted.
- Full Text:
- Date Issued: 2008
- Authors: Dreyer, Nicolaas Burger
- Date: 2008
- Subjects: Intertidal animals -- Ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10700 , http://hdl.handle.net/10948/1070 , Intertidal animals -- Ecology -- South Africa
- Description: Until recently most sandy beach studies have made use of snapshot samples but the validity of this approach has been widely questioned. In this study we attempt to resolve this issue by repeatedly sampling two beaches using a stratified random design. Three sampling sessions took place, each approximately six months apart. The three sites on the first beach were selected according to the type of beach (reflective, intermediate and dissipative) with each morphological type duplicated on the second beach. Many of the physical variables measured had significant differences between the sampling sessions but only a few were significantly different between the Sites. Very few of the individual physical variables had significant relationships with the sandy beach macrofaunal abundance and density. However, composite indices had a greater number of significant relationships with the macrofaunal abundance and density. Also very few significant relationships were seen between the species richness and the physical variables of the beaches studied. Effluent line crossing frequency was the only physical variable that could predict species richness but it was considered a weak predictor. Changes in the zonation patterns within and between beaches were also investigated. The highest concentration of taxa and individuals was found near the low-water mark with a gradual reduction of both towards the high-water mark. Some of the sandy beach community variables (abundance, density and species richness) showed significant difference between the sampling sessions but no significant differences were seen between the two beaches. The presence of three zones was noted using MDS plots and Cluster diagrams. However, using a SIMPER analyses, four zones with the possibility of a fifth was noted.
- Full Text:
- Date Issued: 2008