Showing items 461 - 480 of 1488

Your selections:

Effectiveness of Sampling a Small Sized Network Telescope in Internet Background Radiation Data Collection

  • Authors: Chindipha, Stones D , Irwin, Barry V W , Herbert, Alan
  • Date: 2018
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/427646 , vital:72453 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327624431_Effectiveness_of_Sampling_a_Small_Sized_Net-work_Telescope_in_Internet_Background_Radiation_Data_Collection/links/5b9a5067299bf14ad4d793a1/Effectiveness-of-Sampling-a-Small-Sized-Network-Telescope-in-Internet-Background-Radiation-Data-Collection.pdf
  • Description: What is known today as the modern Internet has long relied on the existence of, and use of, IPv4 addresses. However, due to the rapid growth of the Internet of Things (IoT), and limited address space within IPv4, acquiring large IPv4 subnetworks is becoming increasingly difficult. The exhaustion of the IPv4 address space has made it near impossible for organizations to gain access to large blocks of IP space. This is of great concern particularly in the security space which often relies on acquiring large network blocks for performing a technique called Internet Background Radiation (IBR) monitoring. This technique monitors IPv4 addresses which have no services running on them. In practice, no traffic should ever arrive at such an IPv4 address, and so is marked as an anomaly, and thus recorded and analyzed. This research aims to address the problem brought forth by IPv4 address space exhaustion in relation to IBR monitoring. This study’s intent is to identify the smallest subnet that best represents the attributes found in the/24 IPv4 address. This is done by determining how well a subset of the monitored original subnetwork represents the information gathered by the original subnetwork. Determining the best method of selecting a subset of IPv4 addresses from a subnetwork will enable IBR research to continue in the best way possible in an ever restricting research space.
  • Full Text:
  • Date Issued: 2018

Effectiveness of Sampling a Small Sized Network Telescope in Internet Background Radiation Data Collection

  • Authors: Chindipha, Stones D , Irwin, Barry V W , Herbert, Alan
  • Date: 2018
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/473783 , vital:77681 , xlink:href="https://www.researchgate.net/profile/Barry-Irwin/publication/327624431_Effectiveness_of_Sampling_a_Small_Sized_Network_Telescope_in_Internet_Background_Radiation_Data_Collection/links/5b9a5067299bf14ad4d793a1/Effectiveness-of-Sampling-a-Small-Sized-Network-Telescope-in-Internet-Background-Radiation-Data-Collection.pdf"
  • Description: What is known today as the modern Internet has long relied on the existence of, and use of, IPv4 addresses. However, due to the rapid growth of the Internet of Things (IoT), and limited address space within IPv4, acquiring large IPv4 subnetworks is becoming increasingly difficult. The exhaustion of the IPv4 address space has made it near impossible for organizations to gain access to large blocks of IP space. This is of great concern particularly in the security space which often relies on acquiring large network blocks for performing a technique called Internet Background Radiation (IBR) monitoring. This technique monitors IPv4 addresses which have no services running on them. In practice, no traffic should ever arrive at such an IPv4 address, and so is marked as an anomaly, and thus recorded and analyzed. This research aims to address the problem brought forth by IPv4 address space exhaustion in relation to IBR monitoring. This study’s intent is to identify the smallest subnet that best represents the attributes found in the/24 IPv4 address. This is done by determining how well a subset of the monitored original subnetwork represents the information gathered by the original subnetwork. Determining the best method of selecting a subset of IPv4 addresses from a subnetwork will enable IBR research to continue in the best way possible in an ever restricting research space.
  • Full Text:
  • Date Issued: 2018

Effects of absorptive capacity and knowledge management on innovation capabilities in small, medium and micro enterprises (SMMEs)

  • Authors: Gwena, Courage
  • Date: 2018
  • Subjects: Absorptive capacity (Economics) , Knowledge management , Small business
  • Language: English
  • Type: Thesis , Masters , Business Management
  • Identifier: http://hdl.handle.net/10353/11839 , vital:39111
  • Description: Small Medium and Micro Enterprises (SMMEs) are increasingly becoming an influential factor behind economic growth. On the other hand, knowledge management is credited with being critical to the success of modern business enterprises. Consequently, researchers have a growing interest in understanding knowledge management and its effects on various phenomena within an enterprise. Although SMMEs are tipped to be major providers of employment, innovations and economic growth, it is important that they be investigated in light of factors that influence their sustainability and growth. Notably there is evident lack of research exploring the relationship among absorptive capacity, knowledge management and innovation capabilities from a South African perspective as many of the related studies are concentrated in the developed world. The purpose of the study was to investigate the effects of knowledge management on innovation capabilities in SMMEs with focus on the Buffalo City Metropolitan Municipality. South African SMMEs are experiencing worrying failure rates, whilst on the other hand; knowledge management is credited with organisational success. This trend has presented an opportunity to test how knowledge management affects South African SMMEs innovation capabilities. Above this, the increasing value being attached to SMMEs in solving problems, such as unemployment and trade imbalance have attracted interest as a subject of research. A quantitative research approach was followed in carrying out this study. Descriptive and inferential statistics were performed to answer the research questions of the study. The respondents (n=280) were SMMEs representatives for SMMEs operating in the Buffalo City Metropolitan Municipality. Findings of the study revealed that absorptive capacity exerts positive a effect on the innovative capabilities of SMMEs the same way knowledge acquisition and knowledge sharing were found to have positive statistically significant on the innovation capabilities of SMMEs. The findings also show that knowledge sharing and knowledge acquisition exerts a positive effect on SMMEs innovative capabilities. Findings from the study could assist various practitioners directly or indirectly involved in business development to develop strategies that improve SMMEs growth and sustainability. These practitioners include strategic management researchers, policy makers, SMME owners, managers, and lecturers.
  • Full Text:
  • Date Issued: 2018

Effects of an integrated movement programme on motor proficiency, visual motor integration and scholastic achievement in grade one learners of quintile five primary schools in Port Elizabeth

  • Authors: Lister, Cassandra
  • Date: 2018
  • Subjects: Perceptual-motor learning , Motor ability in children -- South Africa -- Port Elizabeth Self-perception in children -- South Africa -- Port Elizabeth
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10948/22442 , vital:29970
  • Description: Globally, the association between physical fitness, motor proficiency and scholastic achievement has been well researched. However, information concerning the effectiveness of integrated movement programmes in children from various socio-economic disparities, is less well studied. A lack of studies exists on the relationship between perceptual-motor development and scholastic performance in literacy and numeracy in children from low-middle income countries such as in sub-Saharan Africa. Thus, the need exists for educational movement programme implementation in developing countries based on studies of good methodological design, to allow early prevention, identification and rectification of apparent motor deficits in young children. Purpose (Aim): To investigate effects of an integrated movement programme in the classroom setting on motor proficiency, visual-motor integration and scholastic achievement of grade one learners between the ages of six- to nine-years-old in quintile five primary schools in Port Elizabeth. A quasi-experimental research design was used to evaluate the selected dependent variables at baseline assessment on 45 grade one learners from an experimental-and control group in quintile five schools in Port Elizabeth. There were two intervention periods that consisted of a pre-existing classroom-based integrated movement programme (NeuroNet) administered by an internationally accredited teacher to the experimental group. Each intervention period coincided with school terms three and four in 2017 and were a minimum of four weeks long. Pre-test and post-test assessments for all three dependent variables were done at the beginning and end of each term respectively. The learners participated in the integrated movement programme five days per week for 20-minute duration in the classroom. The main two standardised, reliable and valid test batteries used to measure motor proficiency and visual-motor integration were the Bruininks-Oseretsky Test of Motor Proficiency Brief Form (BOT-2 Brief Form) and the Beery-Buktenica Developmental Test of Visual-Motor Integration Full Form sixth edition (Beery VMI). The Beery VMI contained two sub-tests the Beery VMI Visual Perception Test (VMI-VP), and the Beery VMI Motor Coordination Test (VMI-MC), which measured the participants’ visual perception and motor coordination. Scholastic achievement was measured using four domains of the participants’ school reports: numeracy, reading, writing and total scholastic achievement scores. Purposive sampling was used to obtain participants from quintile five primary schools whose principals voluntarily provided consent to undertake the study. Data was collected by trained research assistants and the sole researcher. The Statistica for Windows (StatSoft Incorporated; 2014) software package was used for data analysis. Descriptive data analysis included the means (M) and standard deviations (SD) as measures of central tendency and distribution. Independent t-tests determined between-group differences and the level of significance was set at p<0.05. The magnitude (effect size) of pre-post-intervention differences for both groups was calculated for all variables as Cohen’s d statistic. Subsequent interpretation categories were d<0.20 (insignificant effect), 0.20≤d<0.50 (small effect), 0.50≤d<0.80 (medium effect) and d≥0.80 (large effect) (Gravetter & Wallnau, 2009). The experimental group had statistically significant (p<0.05) higher initial mean values for motor proficiency, visual perception, the reading, writing and total scholastic achievement domains. Motor proficiency showed a mean increase of 10.62±13.97 (24% improvement) in the experimental group compared to a mean increase of 9.63±13.26 (8% improvement) in the control group. A significant final mean between-group difference in motor proficiency was found post-intervention (Diff=16.70, t(43)=3.70, p=0.001; Cohen’s d=1.11: large effect size). Visual-motor integration showed a mean decrease of 5.38±14.34 in the experimental group and a decrease of 8.88±15.39 in the control group. No apparent between-group significant difference occurred for visual-motor integration. Visual perception scores indicated a mean increase of 11.82±18.81 in the experimental group and a mean increase of 15.71±30.03 in the control group. A statistically significant mean between-group difference in visual perception post-intervention was seen (Diff=26.40, t(43) =3.95, p<0.0005; Cohen’s d=1.18: large effect size). Motor coordination showed a mean increase of 20.00±18.45 in the experimental group and decrease of 1.50±23.74 in the control group over the intervention period (Diff=21.50, t(43)=3.36, p=0.002; Cohen’s d=1.00: large effect size). There was a significant between-group mean motor coordination difference post intervention (Diff=19.59, t(43)=2.96, p=0.005; Cohen’s d=0.88: large effect size). The experimental group showed significantly higher mean reading scores pre- 5.67±0.80 and post-intervention 5.43±0.93 compared to the control group pre- 4.13±0.74 and post-intervention 4.63±0.88. Significant between-group differences in reading scores pre- (Diff=1.54, t(43)=6.73, p<0.0005; Cohen’s d=2.01: large effect size) and post-intervention (Diff=0.80, t(43)=2.99, p=0.005; Cohen’s d=0.89: large effect size) were also evident. The experimental group also showed significantly higher mean writing scores pre- 5.62±0.74 and post-intervention 5.05±0.86 compared to the control group pre- 3.83±0.96 and post-intervention 4.21±1.28. A significant between-group difference in writing scores pre- intervention (Diff=1.79, t(43)=6.90, p<0.0005; Cohen’s d=2.06: large effect size) was evident. Total scholastic achievement scores showed an initial significant difference between the experimental- and control group (Diff=1.26, t(43)=6.42, p<0.0005; Cohen’s d=1.92: large effect size). Positive practical significance |r|≥0.300 at (p<0.05) was found between visual-motor integration and reading |r|=0.350; visual perception and writing |r|=0.336; motor coordination and writing |r|=0.318; visual-motor integration and total scholastic achievement |r|=0.330 in the experimental group. In the control group negative practical significance |r|≥0.300 at (p<0.05) was found between visual perception and reading |r|=-0.304, whereas positive practical significance was found between visual perception and writing |r|=0.319; motor coordination and writing |r|=0.340; motor coordination and numeracy |r|=0.378; and motor coordination and total scholastic achievement |r|=0.378 at (p<0.05). The integrated movement programme had significantly positive effects on motor proficiency, visual perception and motor coordination. Motor proficiency had no significant correlation to scholastic achievement domains post-intervention, whereas visual-motor integration significantly correlated to reading and total scholastic achievement; visual perception correlated significantly to writing and negatively to reading; and motor coordination correlated significantly to writing, numeracy and total scholastic achievement. Future longitudinal research incorporating a larger range and scope is needed to fully evaluate the effectiveness of integrated movement programmes on motor proficiency, visual-motor integration and scholastic achievement.
  • Full Text:
  • Date Issued: 2018

Effects of CO2-induced ocean acidification on the early development, growth, survival and skeletogenesis of the estuarine-dependant sciaenid Argyrosomus japonicus

  • Authors: Erasmus, Bernard
  • Date: 2018
  • Subjects: Argyrosomus , Argyrosomus -- Growth , Argyrosomus -- Mortality , Argyrosomus -- Ecology , Argyrosomus -- Physiology , Ocean acidification , Marine ecology -- South Africa , Carbon dioxide -- Physiological effect
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/60585 , vital:27799
  • Description: Although it is increasingly accepted that ocean acidification poses a considerable threat to marine organisms, little is known about the likely response of fishes to this phenomenon. While initial research concluded that adult fishes may be tolerant to changes predicted in the next 300 years, the response of early life stages to end-of-century CO2 levels (~ 1100 µatm according to the IPCC RCP 8.5) remains unclear. To date, literature on the early growth and survival of fishes has yielded conflicting results, suggesting that vulnerability may be species dependant. The paucity of ocean acidification research on fishes is particularly evident when one considers larval skeletogenesis, with no robust studies on its impacts on bone and cartilage development. This study addresses the early life embryogenesis, hatching success, growth, skeletogenesis and survival of an estuarine-dependant species. Dusky kob (Argyrosomus japonicus) were reared in a control (pCO2 = 327.50 ± 80.07 qatm at pH 8.15), intermediate (pCO2 477.40 ± 59.46 qatm at pH 8.03) and high pCO2 treatment (pCO2 910.20 ± 136.45 qatm at pH 7.78) from egg to 29 days post-hatch (dph). Sixty individuals from each treatment were sacrificed at the egg stage and at 2, 6, 13, 18, 21 and 26 dph, measured and stained using an acid-free double- staining solution to prevent the deterioration of calcified matrices in fragile larval skeletons. The proportion of bone and cartilage was quantified at each stage using a novel pixel-counting method. Growth and skeletal development were identical between treatments until the onset of metamorphosis (21 dph). However, from the metamorphosis stage, the growth and skeletal development rate was significantly faster in the intermediate treatment and significantly slower in the high treatment when compared to the control treatment. By 26 dph, A. japonicus reared in high pCO2 were, on average, 47.2% smaller than the control treatment, and the relative proportion of bone in the body was 45.3% lower in the high pCO2 treatment when compared with the control. In addition, none of the fish in the high pCO2 treatment survived after 26 dph. It appears that the combination of the increased energy requirements during metamorphosis and the increased energy cost associated with acid-base regulation may account for reduced growth, skeletogenesis and poor survival in high pCO2. Regardless of the driver, the results of this study suggest that the pCO2 levels predicted for the end of the century may have negative effects on the growth, skeletal development, and survival during metamorphosis.
  • Full Text:
  • Date Issued: 2018

Effects of community based organization programmes on poverty eradication : a case study of Dutywa in Mbhashe municipality, Eastern Cape Province

  • Authors: Maqubela, Zodwa
  • Date: 2018
  • Subjects: Community organization Community development -- South Africa -- Eastern Cape Poverty -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , M. Soc. Sci.
  • Identifier: http://hdl.handle.net/10353/9610 , vital:34803
  • Description: The study set out to establish the effects of CBO’s programmes on poverty eradication in Dutywa Mbhashe Local Municipality, Eastern Cape Province. Poverty is rife in rural areas of Dutywa and community. Community members suffer from both absolute to relative poverty. Community organizations, especially in developing countries, have strengthened the view that these bottom-up organizations are more effective in addressing local needs than larger charitable organizations. This study was done through the reviewing of the implementation of early childhood development programmes, family preservation programmes, victim Empowerment programmes, home community based care programmes (HIV/AIDS), as well as care and support to older person’s programmes by community based organizations with the aim of alleviating poverty. The selection of the district and CBOs was done purposively and data was gathered through focus group discussions, structured and unstructured interviews. Purposive sampling technique was also used in selecting participants who took part in the study. Data analysis was carried out through charts, frequency tables and percentages. Qualitative analysis was carried out through establishing the emerging themes and comparing responses in order to check the validity of the data collected. Quantitative analysis was done through the application of the Statistical Package for Social Science (S.P.S.S). Two objectives were quantitatively analysed and two objectives were qualitatively analysed. The findings revealed that the programmes rendered by the CBOs were effective in the fight against poverty in Mbhashe, Dutywa and it was recommended that there should be an effective monitoring and evaluation of community development programmes and identification of sources of support most especially local sources. It was also recommended that community programme should be aligned with the community cultures.
  • Full Text:
  • Date Issued: 2018

Effects of elastic-band tension training on strength, speed, agility and vertical jump height in university soccer players

  • Authors: Katushabe, Edgar
  • Date: 2018
  • Subjects: Basics of elastic resistance training , Elastic resistance training for stability, strength, and power , Isometric exercise , Soccer -- Training
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10948/30638 , vital:31001
  • Description: Soccer is regarded as one of the most popular sports in the world, and involves explosive physical actions such as kicking, jumping, rapid changes of direction and sprinting. These attributes would suggest that strength, power, and agility may play an important role in soccer performance. Elastic band resistance training serves to increase strength, power, speed, balance, coordination and agility However, there is little published research available on the use and effectiveness of elastic-band resistance training as a tool for improvement in muscular strength and power of soccer players. Purpose: To determine the effect of elastic-band resistance training on strength, speed, agility and vertical jump height of university soccer players. The present study used a pre-test post-test experimental study design. The participants comprised of 15 Eastern Cape male soccer players, currently affiliated with the Nelson Mandela University soccer teams. Participants were randomly allocated into one of two groups: a conventional resistance training group, and an elastic band tension resistance training group. Stratified random sampling was used to ensure an even distribution of the performance levels and training experience between the participants. Analysis implemented used Microsoft Excel® and the latest version of Statistica for the purpose of descriptive and inferential statistics. Additionally, Pearson correlation coefficient and coefficient of determination were used to identify statistical correlations between variables of interest. Inferential statistics were applied using analysis of covariance (ANCOVA), and in the case of significant findings, the Scheffé post-hoc test was utilized for comparisons. Independent t-tests indicated significant between-group differences. The alpha level was set at 0.05. Results: The main findings were that elastic band resistance training would appear to be a superior method to conventional resistance training given that: This method was able to produce greater results in improving maximal vertical jump when compared to free weight resistance training (ANCOVA, F(1,25)=9.1135, p=0.00577), produced faster 40m iv sprint times in comparison to free weight resistance training (ANCOVA, F(1, 25)=4.534, p=0.043), and produced significant improvements in one repetition maximum performance in the squat (ANCOVA, F(1, 25)=5.454, p=0.028). Based on the results of this study, it would appear that both the elastic band resistance training and free weight resistance training were effective in increasing performance in both the one repetition maximum deadlift and agility tests, with no significant difference between the two methods (ANCOVA, F(1, 25) =0.328, p=0.572), ANCOVA, F(1, 25)=3.597, p=0.069 respectively). Elastic band resistance training may be an effective alternative training methodology to improve performance variables in university soccer players. However, further research may be needed to clearly define the role of combined elastic band resistance training in the periodization of soccer training in a competitive season.
  • Full Text:
  • Date Issued: 2018

Effects of Pluronic F127 micelles as delivering agents on the vitro dark toxicity and photodynamic therapy activity of carboxy and pyrene substituted porphyrins

  • Authors: Managa, Muthumuni , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
  • Date: 2018
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/234439 , vital:50196 , xlink:href="https://doi.org/10.1016/j.poly.2018.06.031"
  • Description: Metal free, Zn and ClGa containing carboxyphenoxy and phenoxy groups (complexes 1) and pyrene groups (complexes 2) were synthesized and embedded into Pluronic F127 micelles (represented as F127). Dark toxicity and photodynamic therapy activities of the embedded porphyrins were successfully studied on MCF-7 breast cancer cells. Dark toxicity showed more than 80% cell viability for all complexes. It was found that 1-Zn + F127 showed better photodynamic therapy activity compared to 1-H2 + F127, and 1-ClGa + F127, corresponding to the high partition coefficient for the Zn porphyrin derivatives. The same applies to 2-Zn + F127 compared to 2-H2 + F127, 2-ClGa + F127. 1-ClGa and 1-Zn were also linked to Pluronic F127 silica nanoparticles. PDT activities for embedded 1-ClGa + F127 and 1-Zn + F127 were much higher than when linked to Pluronic silica nanoparticles (PluS NPs), showing the importance of loading of porphyrins into Pluronic F127 as a drug delivering agent rather than linking. PDT studies at the highest concentration of 60 µg/ml showed decrease in cell viability down to 15.9% for 2-Zn + F127. The Kp was determined in biphasic octanol and water system.
  • Full Text:
  • Date Issued: 2018

Effects of polymerisation conditions on the mechanism and properties of furfuryl alcohol resin

  • Authors: Iroegbu, Austine Ofondu
  • Date: 2018
  • Subjects: Polymerization , Polyethylene
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10948/30386 , vital:30937
  • Description: The purpose of this study was to do a comparative investigation on the acid- and heat catalysed polymerisation and resinification of furfuryl alcohol and the effects of these polymerisation conditions on the mechanism, morphology, molecular weight and thermal properties of the polyfurfuryl alcohol resins. The formation of furfuryl alcohol polymers was confirmed using size exclusion chromatography (SEC); the synthesised polymer resins were investigated using Fourier transform infrared spectroscopy (FTIR,), scanning electron microscopy (SEM) and Thermogravimetric analysis (TGA). The effects of polymerisation conditions on the mechanism of polyfurfuryl alcohol polymerisation was a major focus of this study. The obtained results confirm that the surface topology, mechanism of polymerisation, thermal behaviour and molecular weights of polyfurfuryl alcohol polymer resins are dependent on the polymerisation condition. The acid and heat catalysed polyfurfuryl alcohol resin polymers presented interesting and promising results.
  • Full Text:
  • Date Issued: 2018

Effects of production systems and canola meal supplementation on carcass and meat quality characteristics of spent laying hens

  • Authors: Semwogerere, Farouk
  • Date: 2018
  • Subjects: Broilers (Chickens) -- Feeding and feeds Chickens -- Feeding and feeds Chicken industry -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10353/9242 , vital:34309
  • Description: This study evaluated the carcass and meat quality traits of spent laying hens as influenced by production systems (conventional cages and free range) and the inclusion/exclusion of canola meal in their diets. A total of 30 free range and 60 battery cage reared Lohmann Brown-Elite spent laying hens were obtained from a commercial egg producer. The 30 free range hens (53 weeks of age) and 30 of the caged hens (40 weeks of age) were fed a conventional diet, while the remaining 30 caged hens (48 weeks of age) were fed a diet supplemented with canola meal (20 percent). Carcass, portion and organ weights were determined. Physical attributes and proximate composition were analyzed for, with additional fatty acids and sensory profiles being determined for the effects of canola meal inclusion in the diet. Caged hens had heavier (P ≤ 0.05) warm and cold carcasses, thigh, wing and feet compared to free range hens. The percentages of the breast (26.1 ± 0.51 vs. 28.3 ± 0.28), drum, breast bones, breast thaw and cooking losses and thigh cooking loss were lower (P ≤ 0.05) for caged hens than for free range hens. Free range hens had heavier (P ≤ 0.05) gizzards (33.9 ± 1.04 vs. 30.5 ± 0.73) and bones and a lower (P ≤ 0.05) breast meat percentage (47.3 ± 0.94 vs. 51.7 ± 1.35). Meat redness (a*) (0.54 ± 0.222 vs. 1.40 ± 0.135) and hue angle value, skin redness (a*), breast and thigh, Warner-Bratzler shear force (WBSF) values (breast: 12.37 ± 0.411 vs. 17.10 ± 0.751, thigh: 29.68 ± 0.306 vs. 39.75 ± 0.826), breast moisture and thigh ash content were lower (P ≤ 0.05) for caged hens than free range hens. Caged hens had higher (P ≤ 0.05) thigh thaw loss and breast ash content than free range hens. Canola-fed hens had higher (P ≤ 0.05) drum percentages, breast bone weights and percentages, with lower (P ≤ 0.05) thigh and breast meat percentages. Canola-fed hens had lower (P ≤ 0.05) thaw losses, skin yellowness (b*) and Chroma values, breast fat content with higher cooking losses, skin redness (a*) and hue angle value, as well as breast WBSF (12.37 ± 0.411 vs. 15.43 ± 0.600). Palmitic acid, stearic acid, heneicosanoic acid acid, palmitoleic acid, saturated fatty acids (SFA) (34.0 ± 0.56 vs. 38.7 ± 0.71), n-6:n-3 polyunsaturated fatty acids (PUFA) ratio (5.5 ± 0.13 vs. 7.2 ± 0.28), atherogenic index (IA), thrombogenic index (IT), delta-5 desaturase (D5D, elongase index and thiosterase index were lower (P ≤ 0.05) for canola-fed hen breast meat. Breast meat from conventionally fed hens had lower (P ≤ 0.05) myristic acid, lignoceric acid, nervonic acid, alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), PUFA:SFA ratio (0.7 ± 0.05 vs. 0.9 ± 0.02), n-3 PUFA (3.4 ± 0.31 vs. 5.1 ± 0.17), hypocholesterolemic:Hypercholesterolaemic (h/H), stearoyl-CoA desaturase 16 (SCD16) and stearoyl-CoA desaturase 18 (SCD18). The breast meat from conventionally fed hens had lower (P ≤ 0.05) metallic flavor than that from canola-fed hens. Strong positive correlations were observed for overall aroma with chicken (r = 0.965, P < 0.001) and brothy aroma (r = 0.827, P < 0.001); overall aroma with overall flavor (r = 0.680, P < 0.001), chicken flavor (r = 0.668, P < 0.001) and brothy flavor (r = 0.548, P = 0.006); initial juiciness with sustained juiciness (r = 0.771, P < 0.001) and tenderness (r = 0.537, P = 0.007); sustained juiciness with tenderness (r = 0.790, P < 0.001) and chewiness with residue (r = 0.783, P < 0.001). Whilst strong negative correlations were observed for: sustained juiciness with chewiness (r = -0.655, P = 0.001) and residue (r = 0.783, P < 0.001) and for tenderness with chewiness (r = 0.845, P < 0.001) and residue (r = -0.855, P < 0.001). Results of this study highlight that a free range production system when compared to a conventional cage system increased undesirable carcass and physical meat traits of spent laying hens. On the other hand, canola meal inclusion incorporates beneficial health aspects without affecting the sensory profile of meat derived from spent laying hens, both groups of hens being reared in battery cage system. Spent laying hen breasts can be consumed as a functional food (especially canolafed) since the fat content and composition was observed to be close to that which is recommended for a healthy diet.
  • Full Text:
  • Date Issued: 2018

Effects of the carboxylic acid substituents on the photophysical and nonlinear optical properties of asymmetrical Zn (II) phthalocyanines–quantum dots conjugates

  • Authors: Mgidlana, Sithi , Oluwole, David O , Nyokong, Tebello
  • Date: 2018
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/187662 , vital:44684 , xlink:href="https://doi.org/10.1080/24701556.2018.1503684"
  • Description: This work reports on three asymmetrical Zn(II) phthalocyanines, namely: zinc(II) 3–(4-phenoxy)propanoic acid) phthalocyanine(1), zinc(II) 3–(4-phenoxy carboxylic acid) phthalocyanine (2) and zinc(II) 3–(4–oxy)phenoxy)acetic acid phthalocyanine (3) when covalently linked to glutathione(GSH) capped CdTe/ZnSe and CdTe/ZnSe/ZnO quantum dots (QDs). Of the Pc complexes alone, 1 afforded the highest triplet quantum yield (ΦT) value of 0.67 with corresponding largest nonlinear absorption coefficient (βeff) value of 14.0 cm/GW compared to 2 and 3. The conjugates afforded improved triplet quantum yield and nonlinear optical behavior in comparison to the Pc complexes alone.
  • Full Text:
  • Date Issued: 2018

Efficient Biometric Access Control for Larger Scale Populations

  • Authors: Brown, Dane L , Bradshaw, Karen L
  • Date: 2018
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/465667 , vital:76630 , xlink:href="https://www.researchgate.net/profile/Dane-Brown-2/publication/335378829_Efficient_Biometric_Access_Control_for_Larger_Scale_Populations/links/5d61159ea6fdccc32ccd2c8a/Efficient-Biometric-Access-Control-for-Larger-Scale-Populations.pdf"
  • Description: Biometric applications and databases are growing at an alarming rate. Processing large or complex biometric data induces longer wait times that can limit usability during application. This paper focuses on increasing the processing speed of biometric data, and calls for a parallel approach to data processing that is beyond the capability of a central processing unit (CPU). The graphical processing unit (GPU) is effectively utilized with compute unified device architecture (CUDA), and results in at least triple the processing speed when compared with a previously presented accurate and secure multimodal biometric system. When saturating the CPU-only implementation with more individuals than the available thread count, the GPU-assisted implementation outperforms it exponentially. The GPU-assisted implementation is also validated to have the same accuracy of the original system, and thus shows promising advancements in both accuracy and processing speed in the challenging big data world.
  • Full Text:
  • Date Issued: 2018

Electrocatalytic activity of a push-pull phthalocyanine in the presence of reduced and amino functionalized graphene quantum dots towards the electrooxidation of hydrazine

  • Authors: Centane, Sixolile , Sekhosana, Kutloano E , Matshitse, Refilwe , Nyokong, Tebello
  • Date: 2018
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/233456 , vital:50092 , xlink:href="https://doi.org/10.1016/j.jelechem.2018.05.005"
  • Description: We report on the electrochemical behaviour of reduced graphene quantum dots (rGQDs) compared to amino functionalized graphene quantum dots (NH2GQDs). Reduction of the GQDs entails the elimination of the excessive carboxyl and hydrogen groups on the GQDs surface, thereby reducing the energy band gap. The energy band gap of graphene is directly proportional to the available oxygen atoms. The two GQD types were conjugated to a novel cobalt phthalocyanine (cobalt tris-(tert-butyl phenoxy)-mono-carboxyphenoxy phthalocyanine, CoPc) via covalent and nom-covalent interactions. The resulting conjugates were tested towards the electrooxidation of hydrazine. The conjugates are represented as rGQDs(π)CoPc, NH2(π)CoPc, rGQDs@CoPc and NH2GQDs@CoPc. The resulting conjugates were adsorbed onto a glassy carbon electrode using the drop and dry method. The lowest limit of detection (LOD) was obtained for rGQDs(π)CoPc.
  • Full Text:
  • Date Issued: 2018

Electrospinning of carbon nanofibers for investigating the behaviour of lead electrodeposits on the carbon surface

  • Authors: Madikane, Zipporah Kayakazi
  • Date: 2018
  • Subjects: Materials science , Nanotechnology Nanostructured materials
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10948/31622 , vital:31629
  • Description: Over the years, the lead acid battery’s performance in modern vehicles has improved considerably to adapt to the new demands of vehicle electronics and start-stop applications. Although vehicles are valuable for commuting, their high volume of usage has resulted in an increase of fuel prices and emitted carbon dioxide (CO2). Due to the drastic global warming concerns, vehicle manufactures have been pressured into developing a variety of hybrid electric vehicles (HEV) that would reduce their fuel consumption and thereby reduced CO2 emission. The HEVs construction requires the implementation of advanced battery systems that operate under high rate partial state of charge (HRPSoC) conditions. During battery’s discharge, the Pb contained on the negative plate is oxidised to insulating PbSO4 crystals. When the battery is charged, the PbSO4 is reduced back to Pb. With prolonged use at HRPSoC, the battery undergoes an irreversible process wherein small PbSO4 crystallites dissolve and precipitate into large passivating PbSO4 crystals that accumulate as a dense layer on the surface of the negative plate. This layer restricts the diffusion of the H2SO4 electrolyte into the reaction sites for further reactions, resulting in the battery to fail prematurely. Research has shown that the inclusion of appropriate carbon materials on the negative active material (NAM) improves the performance of the batteries in HRPSoC cycling. This study looked at the making of some of the carbon-based additives by using relatively cheap materials such as polyvinyl alcohol (PVA) polymer with a sucrose blend in ratios of 75:25, 50:50 and 25:75, respectively. The blended materials were electrospun into PVA/Sucrose nanofibers. These were further stabilised by iodine and carbonised at 500 °C in a tube furnace. The properties of the carbon fibres were investigated by a number of analytical techniques such as TGA, DSC, XRD, BET, FTIR and SEM. The obtained carbon fibre surfaces were further electroplated with Pb in order to investigate the chemical bonding, the relationship between the carbon-based material interface and the Pb was investigated by SEM and CV techniques. The results of the study demonstrated that the varied ratios of the PVA/Sucrose nanofibers influenced the differences in their respective chemical and physical properties. Thermal analysis demonstrated that at approximately 500 °C, the final residue of the PVA/Sucrose nanofibers decreased as the sucrose content decreased. iii Carbonisation of the nanofibers was confirmed by the structural changes corresponding to the disappearance of the major bonds of PVA and sucrose materials, as well as by the appearance of C=C stretches. Carbonisation was also confirmed by the XRD diffractogram that demonstrated two broad amorphous peaks that corresponded to the planes of the graphite structure. The broadness of the peaks confirmed the amorphous nature of the carbon fibres. The morphological studies demonstrated that upon blending PVA with increasing quantities of sucrose, the uniformity of the fibres was altered into beaded fibrous structures with large diameters due to the increased viscosity of the electrospinning solution. The behaviour of the Pb deposits on the carbon surfaces was influenced by the high quantity of PVA present on the blend and the fibrous structure of the carbonised material. The Pb had high affinity towards the fibrous carbon derived from 75:25 as it deposited widely across the surface. Whereas, the absence of Pb deposits on the surface of the carbon derived from the 25:75 ratio was an indication that the high sucrose content and the bulky non-fibrous structure hindered the electrodeposition. The electrochemical study findings demonstrated that the bare Pb electrode had two distinct current peaks corresponding to the anodic (discharge) and cathodic (charge) reactions of Pb/PbSO4. Upon the inclusion of the electrospun carbon materials on the Pb electrode, the intensities of the anodic and cathodic peaks were reduced. Implying that none of the carbon materials enhanced the electrochemical redox reactions of the Pb/PbSO4 couple in the H2SO4 electrolyte.
  • Full Text:
  • Date Issued: 2018

Electrospun 3, 5-dithienylvinyleneBODIPY embedded polystyrene nanofibers for the photocatalytic degradation of azo dyes in industrial wastewaters

  • Authors: Lebechi, Augustus K , Gai, Lizhi , Shen, Zhen , Nyokong, Tebello , Mack, John
  • Date: 2018
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/187679 , vital:44686 , xlink:href="https://doi.org/10.1142/S1088424618500360"
  • Description: The potential utility of electrospun polystyrene (PS) nanofibers embedded with 2,6-diiodo-8-phenyl-1,7-dimethyl-3,5-di-2-thienylvinyleneBODIPY for the photocatalytic degradation of azo dyes is investigated. A comparison of the singlet oxygen quantum yield of the ππ-extended BODIPY dye in solution and in the PS nanofibers demonstrates that its photosensitizer properties are retained when it is embedded in the solid phase. The photocatalytic degradation properties of the PS nanofibers for Methyl Orange and Orange G were determined by using a Thorlabs 625 nm light emitting diode. The rate of photodegradation increases with the Orange G and Methyl Orange concentration and follows pseudo-first order kinetics at pH 6.7.
  • Full Text:
  • Date Issued: 2018

Elevated CO2 determines cell damage and nitrogen allocation in barley subjected to aphid herbivory

  • Authors: Gallagher, Sean
  • Date: 2018
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/64337 , vital:28535
  • Description: Expected release date-May 2019
  • Full Text:
  • Date Issued: 2018

Emplacement of inflated Pāhoehoe flows in the Naude’s Nek Pass, Lesotho remnant, Karoo continental flood basalt province: use of flow-lobe tumuli in understanding flood basalt emplacement

  • Authors: Jay, Anne E , Marsh, Julian S , Fluteau, F , Courtillot, V
  • Date: 2018
  • Language: English
  • Type: article , text
  • Identifier: http://hdl.handle.net/10962/60752 , vital:27826 , https://link.springer.com/article/10.1007/s00445-017-1189-6
  • Description: Physical volcanological features are presented for a 710-m-thick section, of the Naude’s Nek Pass, within the lower part of the Lesotho remnant of the Karoo Large Igneous Province. The section consists of inflated pāhoehoe lava with thin, impersistent sedimentary interbeds towards the base. There are seven discreet packages of compound and hummocky pāhoehoe lobes containing flow-lobe tumuli, making up approximately 50% of the section. Approximately 45% of the sequence consists of 14 sheet lobes, between 10 and 52-m-thick. The majority of the sheet lobes are in two packages indicating prolonged periods of lava supply capable of producing thick sheet lobes. The other sheet lobes are as individual lobes or pairs, within compound flows, suggesting brief increases in lava supply rate. We suggest, contrary to current belief, that there is no evidence that compound flows are proximal to source and sheet lobes (simple flows) are distal to source and we propose that the presence of flow-lobe tumuli in compound flows could be an indicator that a flow is distal to source. We use detailed, previously published, studies of the Thakurvadi Formation (Deccan Traps) as an example. We show that the length of a lobe and therefore the sections that are ‘medial or distal to source’ are specific to each individual lobe and are dependent on the lava supply of each eruptive event, and as such flow lobe tumuli can be used as an indicator of relative distance from source.
  • Full Text:
  • Date Issued: 2018

Employee motivation, workplace surveillance and employee engagement among selected Zimbabwe revenue authority employees

  • Authors: Tsvangirai, Fidelis Pedzisai
  • Date: 2018
  • Subjects: Employee motivation Employee motivation--Zimbabwe Organizational effectiveness--Zimbabwe
  • Language: English
  • Type: Thesis , Doctoral , Industrial Psychology
  • Identifier: http://hdl.handle.net/10353/17384 , vital:40961
  • Description: Orientation: The study is located in the micro environmental circumstances in Zimbabwe where the size of the informal sector is overtaking that of the formal sector. The country is experiencing a high labour turnover averaging at 19percent per year due to an unstable economic setting. The Zimbabwe Revenue Authority (ZIMRA) is experiencing an employee engagement score as low as 2.1 out of 5. This low employee engagement level and high labour turnover call for employers to find strategies not only to keep their employees motivated and engaged but also to monitor how they work. Research purpose: The study sought to examine how employee motivation mediates between workplace surveillance and employee engagement among selected employees at the Zimbabwe Revenue Authority (ZIMRA). Motivation of the study: Public organisations often face the criticism that they do not deliver the quality of service expected and one in every five of their employees is disengaged from their work. ZIMRA’s mandate has a significant impact on the country’s gross domestic product (GDP) and the organisation needs to deliver against all odds. Currently no research exists which provides information on the mediating effect of employee motivation on the relationship between workplace surveillance and employee engagement in Zimbabwe. Research philosophy, design and method: This study adopted the positivism research philosophy and a survey research design, which is quantitative and descriptive in nature. The study utilised the principles of structural equation modelling (SEM) in formulating the research hypotheses and in data analysis. Main findings: The findings of the study, through utilising SEM, were that a negative relationship exists between workplace surveillance and employee engagement and that employee motivation has a positive significant relationship with employee engagement. The study also found that workplace surveillance positively relates to employee motivation. The study also found that employee motivation partially mediates the relationship between workplace surveillance and employee engagement. Practical/Managerial implications: A negative relationship between workplace surveillance and employee engagement calls for ZIMRA management to seek employee buy-in when implementing workplace surveillance measures. A positive relationship between employee motivation and employee engagement calls for ZIMRA management to invest much in these two variables. A positive relationship between workplace surveillance and employee motivation calls for ZIMRA management to put in place policies that ensure employees do not abuse work time by doing their own business. Contribution or value-add: The study contributes to the body of knowledge on the debate around the impact of employee motivation as a mediator of the relationship between workplace surveillance and employee engagement. This study agree with the vast amount of literature that the relationship between workplace surveillance and employee motivation is not always negative.
  • Full Text:
  • Date Issued: 2018

Employee pension and provident fund rights

  • Authors: Richard, Makhado Fhatuwani
  • Date: 2018
  • Subjects: Pension funds -- Law and legislation -- South Africa , Pension trusts -- South Africa Pensions -- South Africa
  • Language: English
  • Type: Thesis , Masters , LLM
  • Identifier: http://hdl.handle.net/10948/35156 , vital:33642
  • Description: Ideally, every employee is required to retire at some stage in life. Some retire at a relatively early age, whilst others work for as long as is possible. The generally accepted retirement ages are 55, 60 or 65, but vary from company to company as stipulated in the specific company's provident or pension fund rules or policy. Once retired, an individual would rely on social insurance as a source of income in the form of pension or a provident fund. Social insurance, in this regard, refers to the earned benefits of employees and is often linked to formal employment. South Africa, as a middle-income developing country, has incorporated such elements into its social security system. The main aim of a pension or provident fund is to provide benefits for its members when they retire from employment, retrenched, unable to work due to illness and for family in the case a member dies while still working. These forms of social security are key to people’s survival and are referred to as safety nets. benefits. Participation on a voluntary basis by the self-employed is allowed but the take-up has been low Employees’ pension and provident rights under a pension or provident scheme do not arise only under the trusts of the scheme but also as contractual terms of the employment relationship between the employer and its employees. This often takes effect on the date of taking up employment, or on entering into an agreement with the employer. Employment law covers all rights and obligations within the employee employer relationship and covers a range of legal issues such as discrimination, wrongful termination, wages and taxation. Many of these issues are governed by the applicable law. Although the South African retirement fund system is in many respects financially sound and well regulated, several individuals still reach their retirement age with inadequate savings. This occurs for several reasons. For many people, during their working life, the build-up of savings is disrupted, or the costs associated with retirement fund provisioning are relatively high. This problem is not only grave for some workers in the formal sector, but largely for those in the rapidly increasing informal sector. Majority of people still lack effective access to an affordable retirement funding vehicle, for the most part, are completely excluded from social protection schemes, social insurance schemes. The South African retirement fund industry has been heavily influenced by a racially divided past and the parallel existence of developed and emerging components of the economy. In the past, racially discriminatory exclusion from the pension fund or provident fund membership was prevalent. In many cases it was indirect discrimination based on job categorisation, such as the distinction between weekly paid and monthly paid staff. Where the staff complement was racially stratified, people were excluded from membership on the grounds of race. Discrimination in the workplace can deny individuals opportunities and thereby deprive society of what those individuals can and could contribute. This has unfortunately been the case in South Africa’s history, the administration of pension and provident funds being one of many examples.
  • Full Text:
  • Date Issued: 2018

Energy maximisation strategies of different African herbivores in a fire dominated and nutrient poor grassland ecosystem

  • Authors: Brooke, Christopher
  • Date: 2018
  • Subjects: Grassland ecology -- South Africa -- Eastern Cape , Animals -- Food -- South Africa -- Eastern Cape , Herbivores -- Ecology -- South Africa -- Eastern Cape , Fire ecology -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10948/21961 , vital:29807
  • Description: Fire and herbivory are both major drivers in grassland ecosystems throughout the world. Although these two driving forces act independently from one another the relationship between fire and herbivory may be more significant than either acting on their own. Heterogeneity within the landscape as a result of fire results in herbivores having to adapt their behaviour in space and time. My research focussed on 1) characterising the fire regime on Mkambati Nature Reserve (hereafter Mkambati) and 2) determining the foraging choices and energy maximisation principles displayed by herbivores in relation to the biomass of vegetation and post fire vegetation age. Fire regimes were characterised between 2007-2016 in the low nutrient coastal grasslands of Mkambati in terms of fire season, seasonality of fire-prone weather conditions, fire return interval (FRI) and influence of poaching-related ignitions. Based on these results I then assessed foraging choices in terms of energy maximisation of four large herbivore species. I explored what energy maximisation strategy was employed, i.e. maximisation of daily digestible energy (DDE) (recently burnt low biomass vegetation) or instantaneous digestible energy (IDE) (older high biomass vegetation), by herbivore species with different morpho-physiological traits. Common reedbuck (Redunca arundinum), red hartebeest (Alcelaphus buselaphus subsp. caama), zebra (Equus quagga) and eland (Tragelaphus oryx subsp. oryx) were fitted with GPS satellite tracking collars, and hourly GPS locations (observed) were taken between 2008 and 2016. Using mixed effects models, I compared observed and an associated set of random locations to determine the energy maximisation strategy employed by each species. Our results indicated that fires were concentrated in winter when monthly fire danger weather (FDI) was highest. The mean FRI at Mkambati was <3 years, but varied according to vegetation type, and whether censoring (for open ended FRIs) was applied to estimate mean FRIs. Poachers, with the intention of attracting ungulates, are an important source of ignition at Mkambati. Accordingly FRIs were shorter (approximately 2 years) in areas within 3 km of likely poacher entry points. Although all fires recorded at Mkambati during the study period were of anthropogenic origin, mean FRI still fell within the natural range reported for interior grasslands in South Africa. Based on these findings, underpinned by the fire regime information, I showed that red hartebeest and zebra maximised DDE inside and outside of fire seasons and frequently foraged in low biomass recently burnt grasslands. Eland generally favoured areas where they could maximise IDE outside of the fire season, however during the fire season they switched strategy to maximise DDE. Reedbuck did not maximise IDE or DDE at the same scale (patch scale) as the other species, but at a landscape (broader) scale they maximised both IDE and DDE. Through this research I have shown how regular fire affects the foraging and energy maximisation behaviour of large African herbivores and how morpho-physiological traits affect these decisions. In response to these results I recommend that the management of Mkambati implement a focused monitoring program comparing the frequently and less frequently burnt areas of the reserve in order to understand the complex effects of anthropogenic fire and its subsequent effects on the biota of Mkambati.
  • Full Text:
  • Date Issued: 2018
  • Disclaimer
  • Privacy
  • Copyright
  • Contact