Showing papers by "University of South Africa published in 2015"

Worldwide evidence of a unimodal relationship between productivity and plant species richness

Abstract: The search for predictions of species diversity across environmental gradients has challenged ecologists for decades The humped-back model (HBM) suggests that plant diversity peaks at intermediate productivity; at low productivity few species can tolerate the environmental stresses, and at high productivity a few highly competitive species dominate Over time the HBM has become increasingly controversial, and recent studies claim to have refuted it Here, by using data from coordinated surveys conducted throughout grasslands worldwide and comprising a wide range of site productivities, we provide evidence in support of the HBM pattern at both global and regional extents The relationships described here provide a foundation for further research into the local, landscape, and historical factors that maintain biodiversity

Differentiating between descriptive and interpretive phenomenological research approaches.

Abstract: Aim To provide insight into how descriptive and interpretive phenomenological research approaches can guide nurse researchers during the generation and application of knowledge. Background Phenomenology is a discipline that investigates people's experiences to reveal what lies 'hidden' in them. It has become a major philosophy and research method in the humanities, human sciences and arts. Phenomenology has transitioned from descriptive phenomenology, which emphasises the 'pure' description of people's experiences, to the 'interpretation' of such experiences, as in hermeneutic phenomenology. However, nurse researchers are still challenged by the epistemological and methodological tenets of these two methods. Data sources The data came from relevant online databases and research books. Review methods A review of selected peer-reviewed research and discussion papers published between January 1990 and December 2013 was conducted using CINAHL, Science Direct, PubMed and Google Scholar databases. In addition, selected textbooks that addressed phenomenology as a philosophy and as a research methodology were used. Discussion Evidence from the literature indicates that most studies following the 'descriptive approach' to research are used to illuminate poorly understood aspects of experiences. In contrast, the 'interpretive/hermeneutic approach' is used to examine contextual features of an experience in relation to other influences such as culture, gender, employment or wellbeing of people or groups experiencing the phenomenon. This allows investigators to arrive at a deeper understanding of the experience, so that caregivers can derive requisite knowledge needed to address such clients' needs. Conclusion Novice nurse researchers should endeavour to understand phenomenology both as a philosophy and research method. This is vitally important because in-depth understanding of phenomenology ensures that the most appropriate method is chosen to implement a study and to generate knowledge for nursing practice. Implications for research/practice This paper adds to the current debate on why it is important for nurse researchers to clearly understand phenomenology as a philosophy and research method before embarking on a study. The paper guides novice researchers on key methodological decisions they need to make when using descriptive or interpretive phenomenological research approaches.

Green synthesis of Co3O4 nanoparticles via Aspalathus linearis: Physical properties

Abstract: This study reports on the bio-synthesis and the main physical properties of p-type Co3O4 nanoparticles for the first time by a completely green chemistry process using Aspalathus linearis's natural extract as an effective chelating agent. Their surface/interface and optical properties are reported. In addition to the X-ray diffraction investigations, the Raman, and infrared as well as X-ray photoelectron spectroscopies confirmed the single phase of the Co3O4 nanoparticles. As their average size can be as low as ⟨φparticle⟩ ∼3.6 nm, the reticular atomic plans are under a slight compressive state.

Decoloniality as the Future of Africa

Abstract: Decoloniality is not only a long-standing political and epistemological movement aimed at liberation of (ex-) colonized peoples from global coloniality but also a way of thinking, knowing, and doing. It is part of marginalized but persistent movements that merged from struggles against the slave trade, imperialism, colonialism, apartheid, neo-colonialism, and underdevelopment as constitutive negative elements of Euro-North American-centric modernity. As an epistemological movement, it has always been overshadowed by hegemonic Euro-North American-centric intellectual thought and social theories. As a political movement, it has consistently been subjected to surveillance of global imperial designs and colonial matrices of power. But today, decoloniality is remerging at a time when the erstwhile hegemonic Euro-North American-centric modernity and its dominant epistemology are experiencing an epistemological break. This epistemic break highlights how Euro-North American-centric modernity has created modern problems of which it has no modern solutions and how theories/knowledges generated from a Euro-North American-centric context have become exhausted if not obstacles to the understanding of contemporary human issues. This essay introduces, defines, and explains the necessity for decoloniality as a liberatory language of the future for Africa.

A review of Theileria diagnostics and epidemiology.

Abstract: An extensive range of serological and molecular diagnostic assays exist for most of the economically important Theileira species such as T. annulata, T. equi, T. lestoquardi, T. parva, T. uilenbergi and other more benign species. Diagnostics of Theileria is considered with regard to sensitivity and specificity of current molecular and serological assays and their use in epidemiology. In the case of serological assays, cross-reactivity of genetically closely related species reduces the use of the gold standard indirect fluorescent antibody test (IFAT). Development of antigen-specific assays does not necessarily address this problem, since closely related species will potentially have similar antigens. Even so, serological assays remain an important line of enquiry in epidemiological surveys. Molecular based assays have exploded in the last decade with significant improvements in sensitivity and specificity. In this review, the current interpretation of what constitute a species in Theileria and its impact on accurate molecular diagnostics is considered. Most molecular assays based on conventional or real-time PCR technology have proven to be on standard with regard to analytical sensitivity. However, consideration of the limits of detection in regard to total blood volume of an animal indicates that most assays may only detect >400,000 parasites/L blood. Even so, natural parasitaemia distribution in carrier-state animals seems to be above this limit of detection, suggesting that most molecular assays should be able to detect the majority of infected individuals under endemic conditions. The potential for false-negative results can, however, only be assessed within the biological context of the parasite within its vertebrate host, i.e. parasitaemia range in the carrier-state that will support infection of the vector and subsequent transmission.

Recent developments in environmental photocatalytic degradation of organic pollutants: the case of titanium dioxide nanoparticles—a review

Abstract: The presence of both organic and inorganic pollutants in water due to industrial, agricultural, and domestic activities has led to the global need for the development of new, improved, and advanced but effective technologies to effectively address the challenges of water quality. It is therefore necessary to develop a technology which would completely remove contaminants from contaminated waters. TiO2 (titania) nanocatalysts have a proven potential to treat "difficult-to-remove" contaminants and thus are expected to play an important role in the remediation of environmental and pollution challenges. Titania nanoparticles are intended to be both supplementary and complementary to the present water-treatment technologies through the destruction or transformation of hazardous chemical wastes to innocuous end-products, that is, CO2 and H2O. This paper therefore explores and summarizes recent efforts in the area of titania nanoparticle synthesis, modifications, and application of titania nanoparticles for water treatment purposes.

Research Directions on the Adoption, Usage, and Impact of the Internet of Things through the Use of Big Data Analytics

Abstract: The number of devices connected to the Internet of Things (IoT) by the year 2020 may be as high as 75 billion. Long before that, big data analytics will be needed to make use of the data generated by the Internet of Things. While the technical issues needed to create the Internet of Things are substantial, little attention has been given to the behavioral, organizational and business issues that are necessary for a better understanding of the adoption, usage and impact of the IoT. We propose a framework based on the idea that this technology will evolve from monitored "Things", to "Networks of Things", and ultimately to an "Internet of Things". Each of these instantiations of the technology raises adoption, usage and impact issues that can be scrutinized at four levels of analysis: individual, organization, industry, and society. We apply the framework to propose research questions that need to be addressed by researchers.

Shaped Carbons As Supports for the Catalytic Conversion of Syngas to Clean Fuels

Abstract: The conversion of syngas to hydrocarbons via Fischer–Tropsch synthesis (FTS) and to alcohols via higher alcohols synthesis (HAS) are two important chemical reactions that generate liquid fuels. Heterogeneous catalysts supported on carbon have been used in both of these fields. In this review, we first describe the features and surface properties of several shaped carbon materials, including carbon black, activated carbon, carbon nanotubes, carbon nanofibers, carbon spheres, ordered mesoporous carbon, graphene, and diamond. In particular, the microscopic structures of these shaped carbons are compared to differentiate the specific characteristics of different shaped carbons. Then we review the recent advances in the study of heterogeneous catalysts supported on these shaped carbon materials used for FTS and HAS from syngas in the past two decades. Various catalyst parameters, such as promoters, stability, autoreduction, pore structure, carbon morphology, and metal particle size, etc., are discussed and sum...

Applying long short-term memory recurrent neural networks to intrusion detection

Abstract: We claim that modelling network trac as a time series with a supervised learning approach, using known genuine and malicious behaviour, improves intrusion detection. To substantiate this, we trained long short-term memory (LSTM) recurrent neural networks with the training data provided by the DARPA / KDD Cup ’99 challenge. To identify suitable LSTM-RNN network parameters and structure we experimented with various network topologies. We found networks with four memory blocks containing two cells each oer a good compromise between computational cost and detection performance. We applied forget gates and shortcut connections respectively. A learning rate of 0.1 and up to 1,000 epochs showed good results. We tested the performance on all features and on extracted minimal feature sets respectively. We evaluated dierent feature sets for the detection of all attacks within one network and also to train networks specialised on individual attack classes. Our results show that the LSTM classier provides superior performance in comparison to results previously published results of strong static classiers. With 93.82% accuracy and 22.13 cost, LSTM outperforms the winning entries of the KDD Cup ’99 challenge by far. This is due to the fact that LSTM learns to look back in time and correlate consecutive connection records. For the rst time ever, we have demonstrated the usefulness of LSTM networks to intrusion detection.

The influence of corporate social responsibility disclosure on share prices: Evidence from the United Kingdom

Abstract: Purpose – The purpose of this paper is to examine the association between share prices and the level of corporate social responsibility (CSR) disclosure of large UK companies, using CSR data from an independent firm and a time period and setting (the UK) that coincides with increased legislation and increased public awareness of corporate social and environmental issues Against a background of increased interest by investors in CSR disclosure, prior mixed results on the association between CSR disclosure and share prices suggest the need for further research that overcome some of the identified limitations of the extant literature Design/methodology/approach – A modified Ohlson (1995) model is used to examine the relationship between CSR disclosure and share prices among the 100 largest UK companies Three different measures of CSR disclosure are used to ensure robustness of results Findings – The paper finds that higher levels of CSR disclosure are associated with higher share prices Furthermore, the

Mandatory corporate social responsibility assurance practices

Abstract: Purpose – Despite its voluntary nature, the Johannesburg stock exchange (JSE) requires all listed companies to apply the King III principles, including providing independent CSR assurance. King III has accordingly made independent CSR assurance a de facto mandatory requirement, albeit on an “apply or explain” basis. The purpose of this paper is to examine the impact mandatory corporate social responsibility (CSR) assurance practices in South Africa, within a King III context. Design/methodology/approach – To understand the impact of King III on South African CSR assurance practices, a longitudinal study covering reporting periods both before and after King III implementation. The first stage reviewed the annual reports of the 200 largest JSE-listed companies to establish the frequency of CSR assurance provision. The second stage involved performing a content analysis on the CSR assurance reports. Findings – King III is driving the institutionalisation of CSR assurance practices in South Africa, as evidenc...

Vervets revisited: A quantitative analysis of alarm call structure and context specificity

Abstract: The alarm calls of vervet monkeys (Chlorocebus pygerythrus) constitute the classic textbook example of semantic communication in nonhuman animals, as vervet monkeys give acoustically distinct calls to different predators and these calls elicit appropriate responses in conspecifics. They also give similar sounding calls in aggressive contexts, however. Despite the central role the vervet alarm calls have played for understanding the evolution of communication, a comprehensive, quantitative analysis of the acoustic structure of these calls was lacking. We used 2-step cluster analysis to identify objective call types and discriminant function analysis to assess context specificity. Alarm calls given in response to leopards, eagles, and snakes could be well distinguished, while the inclusion of calls given in aggressive contexts yielded some overlap, specifically between female calls given to snakes, eagles and during aggression, as well as between male vervet barks (additionally recorded in South Africa) in leopard and aggressive contexts. We suggest that both cognitive appraisal of the situation and internal state contribute to the variation in call usage and structure. While the semantic properties of vervet alarm calls bear little resemblance to human words, the existing acoustic variation, possibly together with additional contextual information, allows listeners to select appropriate responses.

Application and Uses of Graphene Oxide and Reduced Graphene Oxide

Abstract: Graphene oxide (GO) is a unique material that can be viewed as a single monomolecular layer of graphite with various oxygen-containing functionalities such as epoxide, carbonyl, carboxyl, and hydroxyl groups. When the GO is reduced with a suitable process, the reduced graphene oxide (rGO) formed resembles graphene but contains residual oxygen and other heteroatoms, as well as structural defects. GO and rGO have been used in nanocomposite materials, polymer composite materials, energy storage, biomedical applications, and catalysis, and as a surfactant with some overlaps between these fields. In this chapter, their different uses and applications are described.

Social integration confers thermal benefits in a gregarious primate

Abstract: Sociality has been shown to have adaptive value for gregarious species, with more socially integrated animals within groups experiencing higher reproductive success and longevity. The value of social integration is often suggested to derive from an improved ability to deal with social stress within a group; other potential stressors have received less attention. We investigated the relationship between environmental temperature, an important non-social stressor, and social integration in wild female vervet monkeys (Chlorocebus pygerythrus), using implanted data loggers to obtain direct measures of core body temperature. Heterothermy (as measured by 24-h amplitude of body temperature) increased, and 24-h minima of body temperature decreased, as the 24-h minimum ambient temperature decreased. As winter progressed, monkeys became increasingly heterothermic and displayed lower 24-h minima of body temperature. Monkeys with a greater number of social partners displayed a smaller 24-h amplitude (that is, were more homoeothermic) and higher 24-h minima of body temperature (that is, became less hypothermic), than did animals with fewer social partners. Our findings demonstrate that social integration has a direct influence on thermoregulatory ability: individual animals that form and maintain more social relationships within their group experience improved thermal competence compared to those with fewer social relationships. Given the likely energetic consequences of thermal benefits, our findings offer a viable physiological explanation that can help account for variations in fitness in relation to individual differences in social integration.

The Effect of Thermal Reduction on the Photoluminescence and Electronic Structures of Graphene Oxides

Abstract: Electronic structures of graphene oxide (GO) and hydro-thermally reduced graphene oxides (rGOs) processed at low temperatures (120–180°C) were studied using X-ray absorption near-edge structure (XANES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). C K-edge XANES spectra of rGOs reveal that thermal reduction restores C = C sp2 bonds and removes some of the oxygen and hydroxyl groups of GO, which initiates the evolution of carbonaceous species. The combination of C K-edge XANES and Kα XES spectra shows that the overlapping π and π* orbitals in rGOs and GO are similar to that of highly ordered pyrolytic graphite (HOPG), which has no band-gap. C Kα RIXS spectra provide evidence that thermal reduction changes the density of states (DOSs) that is generated in the π-region and/or in the gap between the π and π* levels of the GO and rGOs. Two-dimensional C Kα RIXS mapping of the heavy reduction of rGOs further confirms that the residual oxygen and/or oxygen-containing functional groups modify the π and σ features, which are dispersed by the photon excitation energy. The dispersion behavior near the K point is approximately linear and differs from the parabolic-like dispersion observed in HOPG.

Mobile Learning: Moving Past the Myths and Embracing the Opportunities.

Abstract: Mobile learning (mLearning) in the open and distance learning landscape, holds promise and provides exciting new opportunities. In order to understand and embrace these opportunities within various contexts and circumstances it is imperative to understand the essence of the phenomenon. In this regard, we first need to understand the core fundamentals of mLearning and gain insight in what mLearning entails. Using critical reflection, this paper clarifies what mLearning is by invalidating myths and misperceptions related to mLearning. Acknowledging the lessons learnt through past experience, the authors then explore the opportunities that mLearning provides. mLearning challenges and risks are discussed to assist those who are keen to embrace these opportunities, in avoiding unnecessary risks and pitfalls. The paper concludes by sharing a few thoughts on the future of mLearning. These perspectives on mLearning seek to provide an overview of what mobile learning entails, recognise the achievements of mobile learning to date, and stimulate an appetite to embrace the opportunities in open and distance learning, while minimising the potential negative effects of technological, social and pedagogical change.

Student privacy self-management: implications for learning analytics

Abstract: Optimizing the harvesting and analysis of student data promises to clear the fog surrounding the key drivers of student success and retention, and provide potential for improved student success. At the same time, concerns are increasingly voiced around the extent to which individuals are routinely and progressively tracked as they engage online. The Internet, the very thing that promised to open up possibilities and to break down communication barriers, now threatens to narrow it again through the panopticon of mass surveillance. Within higher education, our assumptions and understanding of issues surrounding student attitudes to privacy are influenced both by the apparent ease with which the public appear to share the detail of their lives and our paternalistic institutional cultures. As such, it can be easy to allow our enthusiasm for the possibilities offered by learning analytics to outweigh consideration of issues of privacy. This paper explores issues around consent and the seemingly simple choice to allow students to opt-in or opt-out of having their data tracked. We consider how 3 providers of massive open online courses (MOOCs) inform users of how their data is used, and discuss how higher education institutions can work toward an approach which engages and more fully informs students of the implications of learning analytics on their personal data.

Is Poverty in the African DNA (Gene)

Abstract: A 2015 World Bank report on attainment of Millennium Development Goals concludes that the number of extremely poor has dropped substantially in all regions with the exception of Sub-Saharan Africa. We assess if poverty is in the African gene by revisiting the findings of Ashraf and Galor (2013, AER) and reformulating the ‘Out of Africa Hypothesis’ into a ‘Genetic Diversity Hypothesis’ for a ‘Within Africa Analysis’. We motivate this reformulation with five shortcomings arising for the most part from the 2015 findings of the African Gerome Variation Project, notably: limitations in the concept of space, African dummy in genetic diversity, linearity in migratory patterns, migratory origins and underpinnings of genetic diversity in Africa. Ashraf and Galor have concluded that cross-country differences in development can be explained by genetic diversity in a Kuznets pattern. Our results from an exclusive African perspective confirm the underlying hypothesis in a contemporary context, but not in the historical analysis. From a historical context, the nexus is U-shaped for migratory distance, mobility index and predicted diversity while for the contemporary analysis; it is hump-shaped for ancestry-adjusted predicted diversity. Hence, poverty is not in the African gene from a within-Africa comparative standpoint. Policy implications are discussed.

Coalitions in theory and reality: a review of pertinent variables and processes

Abstract: Coalitions and alliances are ubiquitous in humans and many other mammals, being part of the fabric of complex social systems. Field biologists and ethologists have accumulated a vast amount of data on coalition and alliance formation, while theoretical biologists have developed modelling approaches. With the accumulation of empirical data and sophisticated theory, we are now potentially able to answer a host of questions about how coalitions emerge and are maintained in a population over time, and how the psychology of this type of cooperation evolved. Progress can only be achieved, however, by effectively bridging the communication gap that currently exists between empiricists and theoreticians. In this paper, we aim to do so by asking three questions: (1) What are the primary questions addressed by theoreticians interested in coalition formation, and what are the main building blocks of their models? (2) Do empirical observations support the assumptions of current models, and if not, how can we improve this situation? (3) Has theoretical work led to a better understanding of coalition formation, and what are the most profitable lines of inquiry for the future? Our overarching goal is to promote the integration of theoretical and field biology by motivating empirical scientists to collect data on aspects of coalition formation that are currently poorly quantified and to encourage theoreticians to develop a comprehensive theory of coalition formation that is testable under real-world conditions.

Enacting understanding of inclusion in complex contexts: classroom practices of South African teachers

Abstract: While the practice of inclusive education has recently been widely embraced as an ideal model for education, the acceptance of inclusive education practices has not translated into reality in most mainstream classrooms. Despite the fact that education policies in South Africa stipulate that all learners should be provided with the opportunities to participate as far as possible in all classroom activities, the implementation of inclusive education is still hampered by a combination of a lack of resources and the attitudes and actions of the teachers in the classroom. The main purpose of this paper was to develop a deeper understanding of a group of South African teachers’ personal understanding about barriers to learning and how their understanding relates to their consequent actions to implement inclusive education in their classrooms. A qualitative research approach placed within a cultural-historical and bio-ecological theoretical framework was used. The findings, in this paper, indicate that the way in which teachers understand a diversity of learning needs is based on the training that they initially received as teachers, which focused on a deficit, individualised approach to barriers to learning and development, as well as contextual challenges, and that both have direct and substantial effects on teachers’ classroom practices. As a result, they engage in practices in their classrooms that are less inclusive, by creating dual learning opportunities that are not sufficiently made available for everyone, with the result that every learner is not able to participate fully as an accepted member of their peer group in all classroom activities. Keywords : barriers to learning; deficit approach to learning and development; diverse educational needs; inclusive classrooms; inclusive education; mainstream schools; teacher education for inclusion