1834 research outputs found
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The correlation between levels of physical activity, academic performance and self-esteem in grade 4 children in a South African private school
No full textThe study of self-esteem has spanned more than a century, with theorists approaching it from many and varied standpoints. This study aimed to examine the relationship between physical activity, self-esteem and academic achievement in grade 4 children at a private school in South Africa. A correlational research design was used to investigate the relationships between the Piers-Harris Children’s Self-Concept Scale, 2nd Edition, the Physical Activity Questionnaire for Older Children, and Academic Achievement. The results indicated a statistically significant positive correlation between self-esteem and academic achievement (r = 0.420). Correlations were noted between levels of physical activity and physical self-concept (r = 0.486) and between academic achievement and intellectual and school self-concept (r = 0.562). Future research beyond merely correlational analysis would provide more insight into the nature of the relationships.National Research Foundatio
Analysis of grade 12 learners' performance with emphasis on mathematics and physical sciences : what ipact can the olympiads and competitions have?
No full textModulating the expression and activity of the nuclear import protein, Karyopherin β1, in cancer cells
No full textCancer is primarily a disease of disordered gene expression; the dysregulation of thousands of different genes has been associated with the progression of many types of cancer. Previous research from our laboratory aimed at identifying genes differentially expressed in cervical cancer compared to normal patient tissue, found Karyopherin β1 (Kpnβ1), the primary nuclear import protein, to be significantly overexpressed in cervical cancer tissue. Further studies showed that inhibition of Kpnβ1 expression by siRNA resulted in cancer cell death, while non-cancer cells were only minimally affected. These results suggest that Kpnβ1 has potential as an anti-cancer therapeutic target, thus warranting further research into the association between Kpnβ1 expression and cancer progression. In this study, we investigated the biological effects associated with Kpnβ1 overexpression in order to further elucidate the relationship between Kpnβ1 and the cancer phenotype. Our data revealed that Kpnβ1 overexpression, above what was already detected in cancer cells, resulted in reduced proliferation and an associated delay in cell cycle progression. Additionally, overexpression of Kpnβ1 caused changes in the morphology and adhesion properties of cells. Co-expression of Ran, an important nuclear transport factor, binding partner and regulator of Kpnβ1, resulted in a further reduction in proliferation (greater than that of overexpression of either Kpnβ1 or Ran alone), suggesting that cells are particularly unable to handle an imbalance in the levels of Kpnβ1 and Ran. Previous work from our laboratory using a newly identified small molecule, Inhibitor of Nuclear Import-43 (INI-43), showed that INI-43 significantly reduced the proliferation of cancer cells of different tissue origins and interfered with the nuclear import function of Kpnβ1. In order to investigate the specificity of INI-43 for Kpnβ1 in this study, we performed experiments to determine whether overexpression of Kpnβ1 could rescue cancer cells from the negative effects associated with INI-43 treatment. Results revealed that stable overexpression of Kpnβ1 was able to rescue cell viability, as well as the inhibitory effects that INI-43 had on the nuclear import of Kpnβ1 cargoes NFκB p65 and NFAT. Kpnβ1 overexpression was also able to rescue cells from an INI-43 induced G2/M cell cycle block. In addition, treatment of cells with INI-43 enhanced the degradation of Kpnβ1, indicating that INI-43 is likely acting by targeting Kpnβ1. In order to determine the effects of Kpnβ1 dysregulation in HeLa cells, live cell time-lapse videomicroscopy was used to study cells as the progressed through the cell cycle. Inducible expression of Kpnβ1-EGFP, as well as the treatment of cells with the small molecule inhibitor INI-43, were used as mechanisms of dysregulation. Results revealed that modulation of Kpnβ1 by either overexpression or inhibition caused a disruption in mitotic progression, with the appearance of distinct mitotic abnormalities. The treatment of cells expressing Kpnβ1-EGFP with INI-43 resulted in a significant reduction in (or rescue of) the negative effects associated with either condition alone. Taken together, this data suggests that a precise balance of Kpnβ1 expression is required for the correct functioning of cancer cells; when the balance is perturbed in either direction (i.e. with overexpression of Kpnβ1 or INI-43-mediated inhibition of Kpnβ1) negative effects associated with a variety of biological processes are observed. In addition, results from rescue experiments conducted using Kpnβ1 overexpression in combination with INI-43 treatment suggest that that INI-43 is acting, at least in part, by targeting Kpnβ1.National Research Foundatio
Disease dynamics in a metapopulation of Amietia hymenopus
No full textBatrachochytrium dendrobatidis (Bd), a fungal pathogen of amphibians capable of
adversely affecting all levels of organisation up to community level. In South Africa B.
dendrobatidis is widely distributed including in the Drakensberg Mountains where it
infects Phofung river frogs, Amietia hymenopus. Our objective was to identify factors
driving disease dynamics of B. dendrobatidis in A. hymenopus. We made use of a 10
year data set that resulted from monitoring this host-pathogen relationship in
tadpoles from the Mont-aux-Sources region. Tadpoles were collected twice annually
from four rivers: Vemvane, Tugela, Bilanjil and Ribbon Falls. Presence/absence of B.
dendrobatidis was determined through qPCR analysis and cytological screening of
tadpole mouthparts. We found no statistical significant difference between the sites,
but infection was more consistent between years at sites situated along popular
tourist hiking trails. Interestingly, infection prevalence, although higher in summer,
did not differ significantly between seasons. High altitude coincides with moderate
temperatures resulting in a repressed fluctuation on the pathogen’s prevalence
between warmer and colder months. Rainfall, however was negatively correlated
with infection prevalence. Growth rate ratios of tadpoles indicated that tadpole size
and not developmental stage is one of the main drivers of infection. Persistently low
to moderate infection prevalence and low pathogen virulence implies that B.
dendrobatidis acts as an endemic infection in A. hymenopus. Furthermore
microsatellites were developed for this species during this study to aid in population
genetics, unfortunately this was not possible, but it will be very useful for future
conservationNational Research Foundatio
An experimental investigation into the anisotropic behaviour of bovine femoral cortical bone
No full textTo increase our level of knowledge of the human body for various applications, the behaviour of cortical bone needs to be understood. To understand and model the behaviour of cortical bone, knowledge of the strain rate dependent behaviour is required. Many authors have investigated these properties, however, the literature appears to be ambiguous and incomplete, with little focus being placed upon the intermediate strain rate regime (1s⁻¹ to 100s⁻¹). The ambiguity arises as each author presents an averaged data set which does not describe the level of scatter or precise testing methods, nor does it correspond with other authors work [33, 56, 27, 2, 62]. Furthermore, bone should display distinct anisotropic properties due to the microstructural layout. However, no author has published or recorded a complete data set detailing the anisotropy of bone across any species. The intermediate strain rate regime is of particular interest due to Paul [50], capturing a distinct transitional behaviour of cortical bone between low and high strain rates. The apparent lack in intermediate regime research is due to the difficulty in attaining constant strain rate testing conditions within this region using conventional methods. Consequently, due to the absence of data, no accurate model has been developed to simulate the behaviour observed. The focus of this dissertation will therefore be to redesign and fabricate the previously used intermediate strain rate testing device, provide an accurate data set across both quasi-static and dynamic regimes, and a phenomenological model which is able to capture this strain rate dependent behaviour. In order to develop an understanding of the scatter presented in each orientation, light microscopy, inverse light microscopy, and SEM of the specimens is performed. What is observed is that each orientation displays a distinct microstructural layout with fractures propagating in a distinctly different manner based on the strain rate regime. Furthermore, counter to previous findings, the strength of bone across a variety of samples does not appear consistent, however, the longitudinal and radial orientations still display strain rate sensitivity (per sample) which was captured using the improved phenomenological viscoelastic model.National Research Foundatio
Multiple independent colonizations into the Congo basin during the continental radiation of African Mastacembelus spiny eels
No full textThere has been recent interest in the origin and assembly of continental biotas basedon densely sampled species-level clades, however, studies from African freshwaters are fewso that the commonality of macroevolutionary patterns and processes among continentalclades remain to be tested. Within the Afrotropics, the Congo Basin contains the highestdiversity of riverine fishes, yet it is unclear how this fauna was assembled. To address this,and the diversification dynamics of a continental radiation, we focus on African Mastacem-belus spiny eel
Assessing the outcomes and consequences of large carnivore reintroductions to the Eastern Cape, South Africa
No full textReintroduction is a potentially powerful tool available to conservationists to cope with species population declines. Nonetheless, it is poorly understood and past reviews tend to indicate poor results. Reintroduction, under the sensu stricto IUCN definition, must have a primary objective of conservation; however species can be released to sites in their indigenous range (reintroduction sensu lato) to meet other objectives. The outcomes of these reintroductions s.l need to be assessed to determine how effectively they achieve their varied objectives. A Web of Science review revealed that only 32.1% of 131 publications on reintroduction provided clearly defined success criteria. Using economic, ecological, conservation and problem animal management objectives as reintroduction s.l. drivers, I developed context-dependent success definitions for each objective to use in reintroduction outcome assessments. These success criteria were then used to assess the reintroductions s.l. of large carnivores, namely lion, leopard, cheetah, African wild dog, spotted hyaena, and brown hyaena, to 16 private- and state-owned reserves in the Eastern Cape Province, South Africa. Ecotourism and ecological restoration were the most common objectives for the reintroduction of top predators to these reserves. Overall the reintroductions of large carnivores have been successful in meeting their objectives. Only African wild dogs have failed to establish in the province. Causes of objective-specific failures for the other species in some reserves included introductions of same-sex populations, lack of breeding events and changes in reserve management objectives. Assessments for leopard and brown hyaena were inconclusive due to lack of monitoring data. The reintroduction of large carnivores to the Eastern Cape Province has also resulted in the emergence of human-carnivore conflict on neighbouring properties. Carnivores have reportedly escaped from 8 reserves (61.5% of reserves) in the Eastern Cape. A total of 75 conflict events on 68 neighbouring properties (36.7% of neighbouring properties) have been reported. There is a major gap in research around conflict resulting from carnivore reintroductions and future research is required to fully understand the situation in the province in order to develop effective mitigation methods. An adaptive management approach to reintroductions is encouraged to improve monitoring and ensure reintroductions continue to meet their objectives. Furthermore, emerging consequences, such as human-wildlife conflict, and related mitigation strategies should be incorporated into management of reintroduced populations. Communities surrounding reintroduction sites should be educated on lifting baselines where conflict-causing species are recovering to ensure continued success of reintroduction undertakings. National management plans should be developed for all large carnivore species to improve the conservation value of small, fenced reserves that are typical of South African conservation, through a managed metapopulation approach. Management plans should include social, political, and economic factors that can influence the success of reintroductions and ultimate conservation outcomes.National Research Foundatio
Formulation development and thermorheological properties of crumb rubber/eva modified bitumen
No full textThe study deals with the formulation development and thermorheological properties of crumb rubber/ethylene vinyl acetate (EVA) modified bitumen with the aim of optimizing the amount of crumb rubber and EVA loadings in bitumen based on thermorheological parameters complex shear modulus, phase angle and rutting parameter. In the modified binders EVA offers plastomer properties whereas the crumb rubber confers elasticity to the bitumen. 13.75% crumb rubber and 2.5% EVA loadings based on aging indices gave the best optimized mixture. The thermorheological behaviour of the best optimized mixture was compared to industrial grade EVA (AP-1) and crumb rubber (AR-1) modified bitumen. Improving aging behaviour of the bitumen was evaluated using four antioxidants: carbon black, hydrated lime, Irganox 1010 and Irgafos 168. The least aging indices at 58˚C and 64˚C were obtained from a 1:1:1 Irganox 1010/hydrated lime/carbon black mixture. SARA (saturates, aromatics, resins and asphaltene) analysis gave the chemical background for application of antioxidants to reduce the propensity of short term aging. To further improve the EVA/crumb rubber optimized mixture for workability FT wax (Sasobit®) was assayed at loadings from 0-2.5%. This was done to match the EVA content and maintain the original maximum loading of 2.5% in the optimized mixture. The phase change abilities of FT wax owing to the high latent heat enabled co-crystallization with the EVA with the elastomeric backbone of crumb rubber acting as support material. The energy-sustainability nexus was found to have worked at less than 1% loading of FT wax in the EVA/crumb rubber modified bitumen. Response surface methodology approach to all the sections of work was used to come up with the optimized mixtures based on rheological parameters complex shear modulus, phase angle and rutting parameter at test temperature 64˚C. The interaction chemistry of bitumen, crumb rubber, EVA and FT wax was found to be first and second order in all cases involving individual contributions and co-interaction amongst the factors. Project costing for each section of work (optimizing section, antioxidant section and FT wax section) was conducted involving the raw materials used, equipment used, labour involved and other costs incurred for all the project work.National Research Foundatio
Ministerial Guidelines
No full textThe Grants Management and Systems Administration (GMSA) Directorate hosted its 8th annual Research Administrators Workshop (RAW) from 9 to 11 October 2017 in the Western Cape. The workshop aimed to bring together key stakeholders from universities and science councils across South Africa, including international delegates, to share experiences and best practices in research administration and management
Challenges Faced by Institutions Related to Student Support (Consultant)
No full textThe Grants Management and Systems Administration (GMSA) Directorate hosted its 8th annual Research Administrators Workshop (RAW) from 9 to 11 October 2017 in the Western Cape. The workshop aimed to bring together key stakeholders from universities and science councils across South Africa, including international delegates, to share experiences and best practices in research administration and management