Identifying the causes of widespread illegal dumping in Buffalo City Metropolitan Municipality and innovative waste management mechanism
- Authors: Brown, Drayton
- Date: 2020
- Subjects: Waste minimization -- law and legislation -- South Africa -- Buffalo City Metropolitan Municipality
- Language: English
- Type: Thesis , Masters , Degree
- Identifier: http://hdl.handle.net/10948/49767 , vital:41798
- Description: South Africa faces the daily challenge of illegal dumping and authorities cannot seem to contain the problem. This is particularly the case in Buffalo City Metropolitan Municipality (BCMM) as the same non-effective means of curbing illegal dumping is attempted again and again. This study sought to gain insight into why residents would illegally dump waste near their homes considering the numerous negative health and environmental consequences. While many studies have focused on the quantitative aspects of waste management and illegal dumping, none have been conducted in the Eastern Cape or BCMM or enquired as to how citizens felt about the phenomena. This research utilised in-depth semi-structured interviews to gain insight into the problem of illegal dumping through the lenses of both residents and BCMM staff members. One of the key themes within the findings of the study is the apathetic nature of citizens towards their environment. There are also two predominant ways illegal dumping sites form. The first is through ‘Systemic Dumping’ which arises through the lack of waste infrastructure in low income communities and the second is ‘Ad-hoc Illegal Dumping’which form when BCMM does not provide a timely waste management service.
- Full Text:
- Date Issued: 2020
Bioinformatics tool development with a focus on structural bioinformatics and the analysis of genetic variation in humans
- Authors: Brown, David K
- Date: 2018
- Subjects: Bioinformatics , Human genetics -- Variation , High performance computing , Workflow management systems , Molecular dynamics , Next generation sequencing , Human Mutation Analysis (HUMA)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/60708 , vital:27820
- Description: This thesis is divided into three parts, united under the general theme of bioinformatics tool development and variation analysis. Part 1 describes the design and development of the Job Management System (JMS), a workflow management system for high performance computing (HPC). HPC has become an integral part of bioinformatics. Computational methods for molecular dynamics and next generation sequencing (NGS) analysis, which require complex calculations on large datasets, are not yet feasible on desktop computers. As such, powerful computer clusters have been employed to perform these calculations. However, making use of these HPC clusters requires familiarity with command line interfaces. This excludes a large number of researchers from taking advantage of these resources. JMS was developed as a tool to make it easier for researchers without a computer science background to make use of HPC. Additionally, JMS can be used to host computational tools and pipelines and generates both web-based interfaces and RESTful APIs for those tools. The web-based interfaces can be used to quickly and easily submit jobs to the underlying cluster. The RESTful web API, on the other hand, allows JMS to provided backend functionality for external tools and web servers that want to run jobs on the cluster. Numerous tools and workflows have already been added to JMS, several of which have been incorporated into external web servers. One such web server is the Human Mutation Analysis (HUMA) web server and database. HUMA, the topic of part 2 of this thesis, is a platform for the analysis of genetic variation in humans. HUMA aggregates data from various existing databases into a single, connected and related database. The advantages of this are realized in the powerful querying abilities that it provides. HUMA includes protein, gene, disease, and variation data and can be searched from the angle of any one of these categories. For example, searching for a protein will return the protein data (e.g. protein sequences, structures, domains and families, and other meta-data). However, the related nature of the database means that genes, diseases, variation, and literature related to the protein will also be returned, giving users a powerful and holistic view of all data associated with the protein. HUMA also provides links to the original sources of the data, allowing users to follow the links to find additional details. HUMA aims to be a platform for the analysis of genetic variation. As such, it also provides tools to visualize and analyse the data (several of which run on the underlying cluster, via JMS). These tools include alignment and 3D structure visualization, homology modeling, variant analysis, and the ability to upload custom variation datasets and map them to proteins, genes and diseases. HUMA also provides collaboration features, allowing users to share and discuss datasets and job results. Finally, part 3 of this thesis focused on the development of a suite of tools, MD-TASK, to analyse genetic variation at the protein structure level via network analysis of molecular dynamics simulations. The use of MD-TASK in combination with the tools developed in the previous parts of this thesis is showcased via the analysis of variation in the renin-angiotensinogen complex, a vital part of the renin-angiotensin system.
- Full Text:
- Date Issued: 2018
HUMA: A platform for the analysis of genetic variation in humans
- Authors: Brown, David K , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124653 , vital:35642 , https://doi.10.1002/humu.23334
- Description: The completion of the human genome project at the beginning of the 21st century, along with the rapid advancement of sequencing technologies thereafter, has resulted in exponential growth of biological data. In genetics, this has given rise to numerous variation databases, created to store and annotate the ever-expanding dataset of known mutations. Usually, these databases focus on variation at the sequence level. Few databases focus on the analysis of variation at the 3D level, that is, mapping, visualizing, and determining the effects of variation in protein structures. Additionally, these Web servers seldom incorporate tools to help analyze these data. Here, we present the Human Mutation Analysis (HUMA) Web server and database. HUMA integrates sequence, structure, variation, and disease data into a single, connected database. A user-friendly interface provides click-based data access and visualization, whereas a RESTfulWebAPI provides programmatic access to the data. Tools have been integrated into HUMA to allow initial analyses to be carried out on the server. Furthermore, users can upload their private variation datasets, which are automatically mapped to public data and can be analyzed using the integrated tools. HUMA is freely accessible at https://huma.rubi.ru.ac.za.
- Full Text:
- Date Issued: 2018
MD-TASK: a software suite for analyzing molecular dynamics trajectories
- Authors: Brown, David K , Penkler, David L , Amamuddy, Olivier S , Ross, Caroline J , Atilgan, Ali R , Atilgan, Canan , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125138 , vital:35735 , https://doi.10.1093/bioinformatics/btx349
- Description: Molecular dynamics (MD) determines the physical motions of atoms of a biological macromolecule in a cell-like environment and is an important method in structural bioinformatics. Traditionally, measurements such as root mean square deviation, root mean square fluctuation, radius of gyration, and various energy measures have been used to analyze MD simulations. Here, we present MD-TASK, a novel software suite that employs graph theory techniques, perturbation response scanning, and dynamic cross-correlation to provide unique ways for analyzing MD trajectories.
- Full Text:
- Date Issued: 2017
Role of structural bioinformatics in drug discovery by computational SNP analysis: analyzing variation at the protein level
- Authors: Brown, David K , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125921 , vital:35832 , https://doi.10.1016/j.gheart.2017.01.009
- Description: With the completion of the human genome project at the beginning of the 21st century, the biological sciences entered an unprecedented age of data generation, and made its first steps toward an era of personalized medicine. This abundance of sequence data has led to the proliferation of numerous sequence-based techniques for associating variation with disease, such as genome-wide association studies and candidate gene association studies. However, these statistical methods do not provide an understanding of the functional effects of variation. Structure-based drug discovery and design is increasingly incorporating structural bioinformatics techniques to model and analyze protein targets, perform large scale virtual screening to identify hit to lead compounds, and simulate molecular interactions. These techniques are fast, cost-effective, and complement existing experimental techniques such as high throughput sequencing. In this paper, we discuss the contributions of structural bioinformatics to drug discovery, focusing particularly on the analysis of nonsynonymous single nucleotide polymorphisms. We conclude by suggesting a protocol for future analyses of the structural effects of nonsynonymous single nucleotide polymorphisms on proteins and protein complexes.
- Full Text:
- Date Issued: 2017
Structure-based analysis of single nucleotide variants in the renin-angiotensinogen complex:
- Authors: Brown, David K , Olivier, Sheik Amamuddy , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147994 , vital:38700 , https://doi.org/10.1016/j.gheart.2017.01.006
- Description: The renin-angiotensin system (RAS) plays an important role in regulating blood pressure and controlling sodium levels in the blood. Hyperactivity of this system has been linked to numerous conditions including hypertension, kidney disease, and congestive heart failure. Three classes of drugs have been developed to inhibit RAS. In this study, we provide a structure-based analysis of the effect of single nucleotide variants (SNVs) on the interaction between renin and angiotensinogen with the aim of revealing important residues and potentially damaging variants for further inhibitor design purposes.
- Full Text:
- Date Issued: 2017
JMS: a workflow management system and web-based cluster front-end for the Torque resource manager
- Authors: Brown, David K , Musyoka, Thommas M , Penkler, David L , Tastan Bishop, Özlem
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148049 , vital:38705 , https://arxiv.org/abs/1501.06907
- Description: Complex computational pipelines are becoming a staple of modern scientific research. Often these pipelines are resource intensive and require days of computing time. In such cases, it makes sense to run them over distributed computer clusters where they can take advantage of the aggregated resources of many powerful computers. In addition to this, researchers often want to integrate their workflows into their own web servers. In these cases, software is needed to manage the submission of jobs from the web interface to the cluster and then return the results once the job has finished executing.
- Full Text:
- Date Issued: 2015
The role of structural bioinformatics in drug discovery via computational SNP analysis–a proposed protocol for analyzing variation at the protein level:
- Authors: Brown, David K , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/162914 , vital:40996 , doi: 10.1016/j.gheart.2017.01.009
- Description: With the completion of the human genome project at the beginning of the 21st century, the biological sciences entered an unprecedented age of data generation, and made its first steps towards an era of personalized medicine. This abundance of sequence data has led to the proliferation of numerous sequence-based techniques for associating variation with disease, such as Genome-Wide Association Studies (GWAS) and Candidate Gene Association Studies (CGAS). However, these statistical methods do not provide an understanding of the functional effects of variation. Structure-based drug discovery and design is increasingly incorporating structural bioinformatics techniques to model and analyze protein targets, perform large scale virtual screening to identify hit to lead compounds, and simulate molecular interactions. These techniques are fast, cost-effective, and complement existing experimental techniques such as High Throughput Sequencing (HTS).
- Full Text:
- Date Issued: 2017
JMS: an open source workflow management system and web-based cluster front-end for high performance computing
- Authors: Brown, David K , Penkler, David L , Musyoka, Thommas M , Tastan Bishop, Özlem
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/162880 , vital:40993 , doi:10.1371/journal.pone.0134273
- Description: Complex computational pipelines are becoming a staple of modern scientific research. Often these pipelines are resource intensive and require days of computing time. In such cases, it makes sense to run them over high performance computing (HPC) clusters where they can take advantage of the aggregated resources of many powerful computers. In addition to this, researchers often want to integrate their workflows into their own web servers. In these cases, software is needed to manage the submission of jobs from the web interface to the cluster and then return the results once the job has finished executing. We have developed the Job Management System (JMS), a workflow management system and web interface for high performance computing (HPC). JMS provides users with a user-friendly web interface for creating complex workflows with multiple stages. It integrates this workflow functionality with the resource manager, a tool that is used to control and manage batch jobs on HPC clusters. As such, JMS combines workflow management functionality with cluster administration functionality.
- Full Text:
- Date Issued: 2015
Investigating combinations of feature extraction and classification for improved image-based multimodal biometric systems at the feature level
- Authors: Brown, Dane
- Date: 2018
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63470 , vital:28414
- Description: Multimodal biometrics has become a popular means of overcoming the limitations of unimodal biometric systems. However, the rich information particular to the feature level is of a complex nature and leveraging its potential without overfitting a classifier is not well studied. This research investigates feature-classifier combinations on the fingerprint, face, palmprint, and iris modalities to effectively fuse their feature vectors for a complementary result. The effects of different feature-classifier combinations are thus isolated to identify novel or improved algorithms. A new face segmentation algorithm is shown to increase consistency in nominal and extreme scenarios. Moreover, two novel feature extraction techniques demonstrate better adaptation to dynamic lighting conditions, while reducing feature dimensionality to the benefit of classifiers. A comprehensive set of unimodal experiments are carried out to evaluate both verification and identification performance on a variety of datasets using four classifiers, namely Eigen, Fisher, Local Binary Pattern Histogram and linear Support Vector Machine on various feature extraction methods. The recognition performance of the proposed algorithms are shown to outperform the vast majority of related studies, when using the same dataset under the same test conditions. In the unimodal comparisons presented, the proposed approaches outperform existing systems even when given a handicap such as fewer training samples or data with a greater number of classes. A separate comprehensive set of experiments on feature fusion show that combining modality data provides a substantial increase in accuracy, with only a few exceptions that occur when differences in the image data quality of two modalities are substantial. However, when two poor quality datasets are fused, noticeable gains in recognition performance are realized when using the novel feature extraction approach. Finally, feature-fusion guidelines are proposed to provide the necessary insight to leverage the rich information effectively when fusing multiple biometric modalities at the feature level. These guidelines serve as the foundation to better understand and construct biometric systems that are effective in a variety of applications.
- Full Text:
- Date Issued: 2018
Critical success factors to improve direct labour productivity
- Authors: Brown, Conrad Andrew
- Date: 2015
- Subjects: Automobile supplies industry -- Labor productivity -- South Africa , Success in business -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8846 , http://hdl.handle.net/10948/d1020101
- Description: An increase in the global competitiveness has forced manufacturing organisations to re-look their facility from a labour productivity standpoint. Leveraging a manufacturing operation into a competitive avantage must at all times support the organisation’s objective. It is therefore critical that the operation reviews its strategy so that it fulfils the ever changing needs in the market. Purpose – The main objective of this research is to identify the critical success factors to improve direct labour efficiency within Johnson Controls Automotive South Africa (Pty) Ltd (JCI). Design/methodology/approach – A combination of a comprehensive literature review and visits to the Uitenhage plant and head office were employed in the study. JCI practices were observed to highlight the level of direct labour productivity. This was followed by interviewing relevant and key personel who had an involvement in achieving direct labour productivity in the plant. A questionnaire-based research approach was adopted for this purpose and a total of 83 valid survey responses were received from staff in the Uitenhage plant, together with head office staff who directly supported the plant. The questionnaire was designed to identify and test perceptions of employees, regarding the factors of production, identified as sub variables. The research aim was to determine the most practical and effective strategies to improve direct labour productivity. Results were analysed and interpreted after which recommendations were formulated. Findings – Several critical success factors identified as sub variables were tested to understand their impact on direct labour productivity. Empirical results showed that organisational culture, leadership culture, employee engagement, communication and skills, development and training, had a significant effect on direct labour productivity. Respective ratings of these elements were discussed with the focus of improving this going forward. Research limitations/implications – Continued scepticim within JCI about the benefits of direct labour productivity to their business is one of the fundamental limitations this research faces. Originality/value – The novelty of the research project stems from the realization of key factors contributing to the improvement of direct labour productivity within the JCI enviroment. The results would provide JCI with indicators and guidelines for a successful implementation of direct labour productivity initiatives in the Uitenhage plant.
- Full Text:
- Date Issued: 2015
In vitro effects of three organic calcium channel blockers on the rat pineal gland
- Authors: Brown, Clint
- Date: 1992
- Subjects: Calcium -- Antagonists , Pineal gland -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3745 , http://hdl.handle.net/10962/d1003223 , Calcium -- Antagonists , Pineal gland -- Research
- Description: The calcium signal has emerged as an imponant component of intracellular regulation. Pineal function was thought to be slowed by the prominent calcification seen with increasing age, but recently it has been shown that calcium plays a crucial role in the adrenergic regulation of the gland. Beta-adrenoceptor stimulation increases melatonin (aMT) synthesis by increasing the activity of cyclic 3 '-5' adenosine mono phosphate (cAMP). Cyclic-AMP regulates the production of the pineal hormone, melatonin, from serotonin via the rate-limiting enzyme N-acetyltransferase (NAT). Increased intracellular cAMP is essential to the adrenergic induction of NAT. Noradrenaline(NA)also elevates pinealocyte cyclic guanosine monophosphate (cGMP). Adrenergic regulation of these cyclic nucleotides involves both α₁ - and β-adrenoceptors. Beta-adrenoceptor stimulation is an absolute requirement. Alphal-adrenoceptor activation, which is ineffective alone, serves to amplify the β-stimulated cAMP and cGMP responses via a positive effect on a Ca²⁺⁻/ phospholipiddependent protein kinase (Protein kinase-C) and a net influx of Ca²⁺ into the pinealocyte. Previous studies suggest the use of organic calcium channel blockers (CCBs) as probes of calcium-mediated processes. Applying this concept, the study set out to investigate the influence of a representative of each of the structurally diverse groups of calcium channel blockers viz. verapamil, diltiazem and nifedipine, and to examine their effect on β-adrenoceptor stimulation. It used the β-agonist isoprenaline (ISO) and the mixed [α₁/β]agonist noradrenaline (NA), for its combined [α₁/β]adrenoceptor stimulation, on agonist-induced increases in the production of radio-labelled aMT and N-acetylserotonin(aHT) -measured as the sum of N-acetylated product- from [¹⁴C] serotonin. This was done using organ cultures of rat pineal glands. It was speciously assumed that this drug paradigm would allow the determination of Ca²⁺ influx and/or the blocking thereof in the reported potentiation by using ISO as a non Ca²⁺ -entry stimulating agonist, compared with NA and its Ca²⁺ -entry stimulating properties. Surprisingly, all 3 CCB's potentiated the effect of NA. Only diltiazem was found not to potentiate the effect of ISO. In an attempt to uncover the reason for these results, the study moved toward a mechanistic approach,focusing in an antecedent manner on the various steps in the indole metabolic pathway to identify the point at which the change occurred, and hence possibly elucidate the mechanism responsible for the paradoxical increase. Experiments which assayed the levels of NAT, under the same drug conditions, showed the paradoxical increase to be already evident at this stage. Secondary experiments confirmed that NA stimulation of the pineal is dependent on Ca²⁺, both in organ culture and with NAT: the Ca²⁺ chelator EGTA abolished adrenergically-induced stimulation, while Ca²⁺ added after EGTA, restored the enzyme activity. The ionophore A23187 (which is able to transport Ca²⁺ directly into the pinealocyte via a mechanism which differs from the α₁ - mechanism) when used in conjunction with ISO or NA, was able to potentiate the responses of these two agonists relative to control values (agonist-alone), but by itself had no effect. With the enzyme NAT critically dependent upon cAMP for its induction, it was decided to determine the levels of cAMP and then those of its regulator, cAMP-phosphodiesterase (cAMP-PDE). This reasoning was prompted by reports of anti-calmodulin activity shown by the CCBs, in addition to their channel blocking effects. By binding to calmodulin (CaM), the CCBs are reportedly able to inhibit the CaM-dependent activation of cAMP-PDE. Following NA stimulation, verapamil caused a significant decrease in cAMP-PDE levels and an increase in cAMP. The other CCBs showed a similar trend. Glands stimulated with ISO in the presence of verapamil and nifedipine showed no significant differences in cAMP or cAMP-PDE levels. Diltiazem, however, was found to decrease the effect of ISO on cAMP while causing a concomitant increase in cAMP-PDE. This i) supported a possible hypothesis that the observed enhancement is a result of cAMP levels remaining elevated due to an inhibition of cAMP-PDE by the CCEs and ii) pointed to the possible presence of a CaM-sensitive PDE within the rat pineal gland. To test this hypothesis, two drugs which are more specific in their actions on CaM effects were chosen to see if the earlier results could be mimicked and thereby confirmed. Glands stimulated with NA in the presence of the specific CaM inhibitor R 24571 showed increased NAT activity and [¹⁴C]-aMT production. cAMP-PDE levels were clearly down, thus corroborating the possibility of cAMP-PDE inhibition. Glands incubated in the presence of M&B 22948, a CaM-sensitive PDE inhibitor, showed similar increases in NAT activity and [¹⁴C]-aMT. These findings therefore support the initial results and although indirect, confirm the hypothesis that the paradoxical increase following predominantly NA stimulation could be a result of cAMP levels remaining elevated, due to inhibition by the CCEs of the CaM-dependent activation of its regulator cAMP-PDE. In summary, data presented herein concur with proposals that: i) the CCEs are not specific enough to be used as tools to research Ca²⁺ -mediated events, as they appear to have sites of action other than the voltage operated channel (VOC); eg. binding to calmodulin, ii) there are functional differences between the CCEs as shown by diltiazem in this series of experiments, iii) there is a CaM-sensitive-PDE present in the pineal.
- Full Text:
- Date Issued: 1992
"Museum spaces in post-apartheid South Africa": the Durban Art Gallery as a case study
- Authors: Brown, Carol
- Date: 2006
- Subjects: Durban Art Gallery -- History Museums -- South Africa -- Durban Art museums -- South Africa -- Durban Art -- South Africa -- Durban -- Exhibitions Art, Modern -- 20th century -- Exhibitions Art, Modern -- 19th century -- Exhibitions
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2446 , http://hdl.handle.net/10962/d1006231
- Description: This dissertation examines the history of the Durban Art Gallery from its founding in 1892 until 2004, a decade after the First Democratic Election. While the emphasis is on significant changes that were introduced in the post-1994 period, the earlier section of the study locates these initiatives within a broad historical framework. The collecting policies of the museum as well as its exhibitions and programmes are considered in the light of the institution 's changing social and political context as well as shifting imperatives within a local, regional and national art world. The Durban Art Gallery was established in order to promote a European, and particularly British, culture, and the acquisition and appreciation of art was considered an important element in the formation of a stable society. By providing a broad overview of the early years of the gallery, I identify reasons for the choice of acquisitions and explore the impact and reception of a selection of exhibitions. I investigate changes during the 1960s and 1970s through an examination of the Art South Africa Today exhibitions: in addition to opening up institutional spaces to a racially mixed community, these exhibitions marked the beginning of an imperative to show protest art. I argue that, during the political climate of the 1980s, there was a tension in the cultural arena between, on the one hand, a motivation to retain a Western ideal of 'high art' and, on the other, a drive to accommodate the new forms of people's art and to challenge the values and ideological standpoints that had been instrumental in shaping collecting and exhibiting policies in the South African art arena. I explore this tension through a discussion of the Cape Town Triennial exhibitions, organised jointly by all the official museums, which ran alongside more inclusive and independently curated exhibitions, such as Tributaries, which were shown mainly outside the country. The post-1994 period marked an opening up of spaces, both literally and conceptually. This openness was manifest in the revised strategies that were introduced to show the Durban Art Gallery 's permanent collection as well as in two key public projects that were started - Red Eye @rt and the AIDS 2000 ribbon. Through an examination of these strategies and initiatives, I argue that the central role of the Durban Art Gallery has shifted from being a repository to providing an interactive public space.
- Full Text:
- Date Issued: 2006
The initial grounding of rational numbers : an investigation
- Authors: Brown, Bruce John Lindsay
- Date: 2007
- Subjects: Number theory Numbers, Rational -- Study and teaching (Elementary) Numeracy -- Study and teaching (Elementary) Mathematics -- Study and teaching (Elementary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1904 , http://hdl.handle.net/10962/d1006351
- Description: This small scale exploratory research project investigated the grounding of rational number concepts in informal, everyday life situations. A qualitative approach was taken to allow for the identification and then in depth investigation, of issues of importance for such a grounding of rational number understanding. The methodology followed could be seen as a combination of grounded theory and developmental research. And the data was generated through in-depth and clinical interviews structured around a number of grounded tasks related to rational numbers. The research comprised three cycles of interviews that were transcribed and then analysed in detail, interspersed with periods of reading and reflection. The pilot cycle involved a single grade three teacher, the second cycle involved 2 grade three teachers and the third cycle involved 2 grade three children. The research identified a number of different perspectives that were all important for the development of a fundamental intuitive understanding that could be considered personally meaningful to the individual concerned and relevant to the development of rational number concepts. Firstly in order to motivate and engage the child on a personal level the grounding situation needed to be seen as personally significant by the child. Secondly, coordinating operations provided a means of developing a fundamental intuitive understanding, through coordination with affording structures of the situation that are relevant to rational numbers. Finally, goal directed actions that are deliberately structured to achieve explicit goals in a situation are important for the development of more explicit concepts and skills fundamental for rational number understanding. Different explicit structures give rise to different interpretations of rational numbers in grounding situations. In addition to these perspectives, it became evident that building and learning representations was important for developing a more particularly mathematical understanding, based on the fundamental understanding derived from the child's grounded experience. The conclusion drawn in this research as a result of this complexity, is that to achieve a comprehensive and meaningful grounding, children's learning of rational numbers will not follow a simple linear trajectory. Rather this process forms a web of learning, threading coordinating operations for intuitive development, interpretations for explicit grounding and representations to develop more formal mathematical conceptions.
- Full Text:
- Date Issued: 2007
Teacher education for Mathematical Literacy: a modelling approach
- Authors: Brown, Bruce J L , Schäfer, Marc
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141040 , vital:37939 , DOI: 10.4102/pythagoras.v0i64.98
- Description: This paper reports on a study of the extent to which question design affects the solution strategies adopted by children when solving linear number pattern generalisation tasks presented in pictorial and numeric contexts. The research tool comprised a series of 22 pencil-and-paper exercises based on linear generalisation tasks set in both numeric and two-dimensional pictorial contexts. The responses to these linear generalisation questions were classified by means of stage descriptors as well as stage modifiers. The method or strategy adopted was analysed and classified into one of seven categories. In addition, a meta-analysis focused on the formula derived for the nth term in conjunction with its justification. The results of this study strongly support the notion that question design can play a critical role in influencing learners' choice of strategy and level of attainment when solving pattern generalisation tasks. An understanding of the importance of appropriate question design has direct pedagogical application within the context of the mathematics classroom.
- Full Text:
- Date Issued: 2006
Where are the men? : an investigation into female-headed households in Rini, with reference to household structures, the dynamics of gender and strategies against poverty
- Authors: Brown, Brenda
- Date: 1996
- Subjects: Women heads of households -- South Africa , Poor women -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2097 , http://hdl.handle.net/10962/d1002660 , Women heads of households -- South Africa , Poor women -- South Africa
- Description: An in-depth study is conducted into ten female-headed households in the township of Rini, an underprivileged section of Grahamstown in the Eastem Cape region of South Africa. The study provides information on the way in which such households function in conditions of poverty and underemployment. The meaning of the term 'household' is clearly defined. A household consists of a group of people, who may or may not be kin-related, but who usually live under the same roof, eat together and share resources. Household members may be absent for varying periods of time, but are still considered to have rights in the household to which they belong. The female-headed household usually contains a core of adult women who are often uterine kin. Men are frequently members of these households and are usually related to the women who form the core. Their status and roles in such households are defined and intra-household relations between household members are discussed. In this study, female headship is observed to occur in conditions of poverty when an elderly woman is widowed, receives a regular income in the form of and old age pension, and when her status as the senior member of the household is acknowledged. The presence of men in female-headed households has not been widely emphasised in other studies, either of the female-headed household itself, or in research done in this area of South Africa. An attempt is therefore made to illustrate the way in which men function in these households and the varying roles they play. An attempt is also made to describe other structures and practices which support the female-headed household in a rapidly changing urban environment. These include church membership, burial society membership, the informal economy, wider kinship networks and, in the case of the men, the rite of circumcision.
- Full Text:
- Date Issued: 1996
A preliminary investigation of the ecology of the Larger Kleinmond River Estuary, Bathurst District
- Authors: Brown, Alexander Claude, 1931-2005
- Date: 1953
- Subjects: Kleinemonde River Estuary (South Africa) , Estuaries -- South Africa , Estuarine ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5904 , http://hdl.handle.net/10962/d1014611
- Description: Introduction. On the coast of the Bathurst Division, Eastern Cape Province, some 42 miles south- east of Grahamstown, lie two estuaries opening within a few yards of one another. These are known as the Kleinemonde. This paper embodies the results of an ecological survey of the fauna of the Larger Kleinmond Estuary. The chief concern has been the aquatic fauna but animals living along the banks have also been dealt with as far as possible, as have the birds. This is the second of South Africa's blind estuaries to be studied, the Klein River, Hermanus, having been investigated in 1947-49 by workers from the University of Cape Town. Though common in South Africa, blind estuaries are rare in parts of the world such as Europe, and present an almost entirely new field of research for the ecologist. It is hoped, therefore, that the investigation of the Kleinmond Estuary and a comparison with the results obtained from the Klein River, Hermanus, will add to our knowledge of this subject and be of service to future investigators. The history of the Kleimnond River is worthy of mention, for the lagoon was not always blind and shallow. The early maps of the 1820 settlers show the river as a navigable stream; sailing vessels anchored out at sea and sent lighters up what was then known as the Lydendoch River to collect fresh meat. The area at the mouth of the river was called Port Jessie. In these early days the region abounded with game. Hippo and elephant were common. the former inhabiting deep pools in the upper reaches of the river; pools which have since completely silted up. Constant ploughing of the slopes adjoining the river has caused vast amounts of soil to be washed by rains into the stream, and today what was within living memory a deep, clear stream is a shallow, blind and muddy river, a reflection of man's destructive methods of farming. These changes must have had a far-reaching effect on the fauna of the estuary; an effect about which we can, alas, only speculate. It is perhaps significant that though rich in numbers, the fauna is poor in species, tunicates and echinoderms being apparently entirely absent. The work involved in this survey was undertaken between September 1952 and November 1953, under the direction of Professor J . Omer-Cooper of Rhodes University, frequent and regular visits being made to the estuary. The entire month of February, 1953, was spent on the shore of the lagoon, so that animals could be observed over a continuous period. The starting date of the survey was particularly fortunate, as on September 28th, 1952, the river came down in flood and broke through the sand-bar separating the lagoon from the sea. The work thus began at a definite point in the estuarine cycle, the importance of which it is hoped to show.
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- Date Issued: 1953
The diary of James Brownlee
- Authors: Brown, Alastair Graham Kirkwood
- Date: 1981
- Subjects: Brownlee, James, 1824-1851 -- Diaries , South Africa -- History -- Frontier Wars, 1811-1878
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2598 , http://hdl.handle.net/10962/d1007678 , Brownlee, James, 1824-1851 -- Diaries , South Africa -- History -- Frontier Wars, 1811-1878
- Description: James Brownlee was born in April 1824. He was the second of three sons (and five daughters) born to the missionary John Brownlee, and his colonial born wife Catharine. The importance of James as an historical character is obscured by that of his father and elder brother Charles. James had a varied career which was cut short by his untimely death in March 1851 at the youthful age of twenty-six years and eleven months. We are fortunate that he has left a vivid account of several aspects of the seventh Frontier War in a diary which he kept from April to September 1846. The diary also points to the significance of his family in the history of the Eastern Cape. Thesis, p. 1.
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- Date Issued: 1981
Phases of sustainable development in small and medium enterprise (SME) retail outlets
- Authors: Brower, Marlon
- Date: 2009
- Subjects: Sustainable development -- South Africa -- Nelson Mandela Bay Municipality , Small business -- South Africa -- Nelson Mandela Bay Municipality , Outlet stores -- South Africa -- Nelson Mandela Bay Municipality
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8806 , http://hdl.handle.net/10948/d1018506
- Description: SMEs play a vital role in the country. For the purpose of the study the focus was on SMEs in the Nelson Mandela Bay Municipality Jurisdiction. Businesses which met the SME criteria (refer to Chapter 1, Section 1.7.1), (Du Plessis, 1996: 162; Marx et al., 1998: 728) were included in this study. The study is formed around the aspects of business which contribute to the growth of the business in the long term. A specific study was conducted on the ethnic entrepreneur and the aspects that influence business growth. There are many factors which influence the growth of the business; for the purpose of this study, a specific focus was placed on: (1) knowledge with regard to business; (2) entrepreneurial culture; (3) brand management; (4) location of the business; (5) business relationships; and (6) cultural influences. These variables will determine how the growth of the business is ultimately influenced. The research can also discover from respondents what they view as important in their lives. The study then goes further to analyse whether the independent variables, as reacted to by the respondents, have a significant or non-significant effect on growth.
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- Date Issued: 2009
Biology, population dynamics and management of carpenter (Argyrozona argyrozona) an endemic South African reef fish
- Authors: Brouwer, Stephen Leonard
- Date: 2005
- Subjects: Reef fishes -- South Africa Sparidae -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5241 , http://hdl.handle.net/10962/d1005084
- Description: Carpenter, Argyrozona argyrozona (Valenciennes, 1830), is an endemic South African sparid fish. They form an important component of the commercial linefishery on the South African east coast, where they are the third most important species landed. Recent investigations revealed that the catch per unit effort (cpue) of this species has declined markedly since the early 1900’s. Despite these declines and the importance of this resource, remarkably little biological information on this species exists for providing management advice. This thesis investigates the life history of carpenter, particularly those aspects that are used for management. This includes an investigation into the stock distribution and identification of nursery areas, and an assessment of age, growth, reproduction and movement patterns. Age and growth was assessed using methods based on both otoliths and mark-recapture. Transverse sagittal sections from the Tsitsikamma National Park showed clear opaque and translucent growth increments. Marginal growth zone analysis and mark-recapture of chemically tagged fish (Oxytetracycline) revealed that these were deposited on an annual basis: opaque in summer and translucent in winter. A. argyrozona were found to be long lived (up to 27 years) and slow growing. Within reader (between counts) and between readers average percent error (APE) was 5.3 and 1.8, respectively, showing that readability of carpenter otoliths is high. Comparison between whole and sectioned otoliths showed that the former significantly under-estimated the age of fish older than 10 years (p<0.01). A large proportion (68%) of the individual growth rates derived from mark-recapture data were below those predicted by the otolith based von Bertalanffy growth model (p<0.01). This was attributed to the negative influence of external tags, as hydroids, frequently occurring on the tags of recaptured fish, were observed to cause severe lesions and in some cases, extensive fin damage. This brings into question the use of mark-recapture studies to calculate growth of some species. The effects of sampling design and sample size on age and growth estimation were assessed. The minimum sample size required to accurately estimate growth and mortality, and the effects of using either random or stratified sampling procedures were tested. Decimal and integer ageing both produced similar estimates of von Bertalanffy growth parameters, growth curves, spawner biomass-per-recruit (SB/R) and fishing mortality (F) estimates. Sampling monthly throughout the year and collecting data in a single large sample provided similar growth curves, von Bertalanffy, F and SB/R estimates. The data showed that estimates based on less than 300 random samples were unreliable. However, accurate growth parameter estimates were achievable with less than 200 samples if the sample was stratified with 10 or more samples per 2 cm size class. An investigation into the reproductive biology of A. argyrozona within the Tsitsikamma National Park revealed that they were serial spawning late gonochorists. The size at 50% maturity (L₅₀) was estimated at 292 and 297 mm FL for females and males, respectively. Both monthly gonadosomatic indices and macroscopically determined ovarian stages strongly suggest that A. argyrozona within the Tsitsikamma National Park spawn in the austral summer between November and April. The presence of post-ovulatory follicles (POF's) confirmed the six month spawning season, while monthly proportions of early (0-6 hour old) POF's showed that spawning frequency was highest (once every 1-2 days) from December to March. Although spawning season was more highly correlated to photoperiod (r = 0.859) than temperature (r = -0.161), the daily proportion of spawning fish was strongly correlated (r = 0.93) to ambient temperature over the range 9-22⁰C. Both spawning frequency and season increased with fish length. As a result of the allometric relationship between annual fecundity and fish mass a 3 kg fish was calculated to produce 5 fold more eggs per kilogram of body weight than a fish of 1 kg. In addition to producing more eggs per unit weight each year, larger fish also produce significantly larger eggs. Adult emigration and larval dispersal of A. argyrozona from the Tsitsikamma National Park (TNP), South Africa, were investigated using mark-recapture data and Acoustic Doppler Current Profiler measurements of currents. Tagging data showed that adult carpenter were mainly resident, with a small proportion (7%) leaving the TNP in both easterly and westerly directions. No relationship was found between fish movement patterns and fish size or time-at-liberty. Current patterns suggest that eggs and larvae spawned within the TNP are mainly transported eastwards towards established nursery grounds; the median estimated distance moved was 299 km (range 42-561 km) in 30 days (time to flexion). Given this pattern of ichthyoplankton dispersal together with the fact that adult carpenter within the TNP display a high degree of residency and that they are much more abundant than in adjacent fishing grounds (cpue = 23 times greater), it appears that the TNP protects a viable carpenter spawner population capable of seeding adjacent fishing grounds. Fishery independent biomass surveys and commercial linefish catch returns were used to elucidate the spatial patterns of A. argyrozona distributed along the South African continental shelf. Two distinct areas of abundance were determined, one on the central and the other on the eastern Agulhas Bank. Tagging studies revealed little exchange between them. Two distinct nursery areas were identified. These data suggest that in each area juvenile A. argyrozona settle and move inshore, and then move offshore as they grow. Otolith readability and growth rates varied between regions, with fish from the Eastern Cape having the lowest average percentage error and the slowest growth rates, readability decreased westward. L₅₀ varied between the central and eastern Agulhas Bank as did mass at length. Based on the distribution of carpenter, variability in otolith readability, mass at length, variation in growth and size at maturity, it is concluded that carpenter exist as two separate stocks, one on the central Agulhas Bank and the other on the eastern Agulhas Bank. SB/R, fecundity-per-recruit (Egg/R) and yield-per-recruit (Y/R) models were used to model both South African carpenter stocks. Owing to the allometric relationship between annual fecundity and individual size, Egg/R ratios were between 40 and 74% of SB/R at equivalent F. Egg/R ratios account for allometric increases in fecundity with size/age, and are therefore regarded as more accurate estimates of reproductive potential, and biological reference points for per-recruit analysis should wherever possible be based on this quantum. It is shown that the current length at first capture (lc) (250 mm TL) and F (at M = 0.1) will reduce Egg/R to 6.41% of the pristine value in the Eastern Cape and between 6.06 and 14.15% on the central Agulhas Bank, indicating that both stocks are heavily over exploited. An increase in lc from 250 to 350 mm TL and a 70% reduction in commercial fishing effort is recommended to attain a target reference point of 40% Egg/RF=0. Bag frequency analysis indicates that a reduction in daily bag limit from 10 to 4 fish.person¹.day⁻¹ would effect an equivalent reduction in recreational F. The trawl bycatch of carpenter is only 3% of the reported line catch, consequently restrictions to this fishery are not recommended.
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- Date Issued: 2005