Anti-HIV-1 integrase potency of methylgallate from Alchornea cordifolia using in vitro and in silico approaches:
- Authors: Noundou, Xavier S , Musyoka, Thommas M , Moses, Vuyani , Ndinteh, Derek T , Mnkandhla, Dumisani , Hoppe, Heinrich C , Tastan Bishop, Özlem , Krause, Rui W M
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/162975 , vital:41001 , https://0-doi.org.wam.seals.ac.za/10.1038/s41598-019-41403-x
- Description: According to the 2018 report of the United Nations Programme on HIV/AIDS (UNAIDS), acquired immune deficiency syndrome (AIDS), a disease caused by the human immunodeficiency virus (HIV), remains a significant public health problem. The non-existence of a cure or effective vaccine for the disease and the associated emergence of resistant viral strains imply an urgent need for the discovery of novel anti-HIV drug candidates. The current study aimed to identify potential anti-retroviral compounds from Alchornea cordifolia.
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Behaviour of an alpine range-restricted species is described by interactions between microsite use and temperature
- Authors: Oswald, Krista N , Smit, Ben , Lee, Alan T K , Cunningham, Susan J
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441531 , vital:73896 , https://doi.org/10.1016/j.anbehav.2019.09.006
- Description: Climate change predictions include increased mean temperatures and increased frequency of heatwaves. Short-term responses to high air temperatures can allow animals to conserve water while maintaining a safe body temperature. For birds, cooling is often through evaporative water loss, which can be physiologically costly. Microsite use is an effective means of conserving water via reducing environmental heat load, so long as there are no negative trade-offs with other necessary functions, such as foraging. We examined behavioural responses to temperature in Cape rockjumpers, Chaetops frenatus (hereafter: ‘rockjumper’), an alpine specialist bird. We hypothesized that rockjumper behaviours would be temperature and microsite dependent. We collected data on rockjumper microsite use (sun, rock shade), behaviour (activity, foraging, preening, panting) and temperature (air, environmental). Rockjumpers made increased use of rock shade as air temperature increased. However, birds in rock shade foraged less. Depending on where their main food source is located, this suggests that when foraging demands are high, birds may need to remain in the sun despite risks of high thermal load, or else may suffer costs of lost foraging opportunities when using shade. The relationship between air temperature and heat dissipation behaviour (panting) was also mediated by microsite: birds showed significant increases in panting with increasing air temperature only when in the sun. The lack of increase in panting for birds in rock shade suggests that shade seeking may buffer physiological thermoregulatory costs (i.e. water expenditure). Individuals may therefore be able to mitigate some potential negative effects of high temperatures by making use of cooler microsites, although this could come at a cost to foraging.
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Focus on ‘the family’? How South African family policy fails queer families
- Authors: Macleod, Catriona I , Morison, Tracy , Lynch, Ingrid
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434398 , vital:73054 , ISBN 9780367777401 , https://www.routledge.com/Queer-Kinship-South-African-Perspectives-on-the-Sexual-politics-of-Family-making-and-Belonging/Morison-Lynch-Reddy/p/book/9780367777401
- Description: The most policy document is the White Paper on Families, which aims to facilitate the mainstreaming of a family perspective into all government policy-making from the national to the municipal level and across multiple departments. The irony is that less than a third of South African families actually conform to the two cisgender heterosexual biological parent model that is favoured in family policy. South African research has shown that children of lesbian parents learn open-mindedness and to be comfortable with the family in which they live, and that men in same-sex relationships challenge gendered divisions of household tasks. Promoting the two-biological-parent family as the preferred family structure creates an impossible ideal for the majority of South Africans to live up to. Because such a family structure is strongly connected to class, it is out of reach for the majority of citizens, let alone those who live in queer relationships.
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Food web structure and trophic dynamics of a fish community in an ephemeral floodplain lake
- Authors: Peel, Richard A , Hill, Jaclyn M , Taylor, Geraldine C , Weyl, Olaf L F
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444690 , vital:74260 , https://doi.org/10.3389/fenvs.2019.00192
- Description: In Africa, wetlands, such as shallow, ephemeral lakes provide ecosystem services, such as water purification, food supply, and flood control but are subject to dynamic flooding/drying cycles which vary in duration from years to decades. The stochastic nature of drying events subjects ephemeral lake fauna to persistent disturbance regimes, therefore understanding how biota respond to flooding and drying events is essential for their conservation and management. Primary production sources supporting consumer biomass in the shallow ephemeral Lake Liambezi (upper Zambezi Ecoregion), were investigated using stable isotope analysis, mixing models and stomach content analysis to investigate the following hypotheses: (1) algal primary production supports a higher consumer biomass than aquatic macrophytes; (2) the lake food chain is short, because the majority of fish fauna are detritivorous/herbivorous cichlids that are consumed by top predators; (3) fish community trophic structure will be similar between years; and (4) with short food chains and stochastic resource availability, there will be substantial competition for food among fish species.
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International book donors and public libraries as partners in primary school literacy development in Kenya:
- Authors: Mose, Peter , Kaschula, Russell H
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/174783 , vital:42509 , https://doi.org/10.1108/LM-05-2018-0046
- Description: The purpose of this paper is to explore the impact of international library materials aid in primary schools and to outline obstacles to effective utilization for maximum literacy benefits among primary school children. Data were gathered via interviews, observation, focus group discussions and document analyses.
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Outcome of illustrated information leaflet on correct usage of asthma-metered dose inhaler:
- Authors: Wrench, Wendy W , Van Dyk, Lynette , Srinivas, Sunitha C , Dowse, Roslind
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156640 , vital:40033 , https://doi.org/10.4102/phcfm.v11i1.2079
- Description: Research globally has shown that metered dose inhaler (MDI) technique is poor, with patient education and regular demonstration critical in maintaining correct use of inhalers. Patient information containing pictorial aids improves understanding of medicine usage; however, manufacturer leaflets illustrating MDI use may not be easily understood by low-literacy asthma patients. To develop and evaluate the outcome of a tailored, simplified leaflet on correct MDI technique in asthma patients with limited literacy skills.
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Poverty reduction strategies and non-timber forest products
- Authors: Pullanikkatil, Deepa , Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433583 , vital:72985 , ISBN 978-3-319-75580-9 , https://link.springer.com/chapter/10.1007/978-3-319-75580-9_1
- Description: The first of the 17 Global Goals that make up the 2030 Agenda for Sustainable Development is to end poverty in all its forms everywhere. Although the numbers of poor people in the world has declined over the last few decades, it is still alarmingly high, being approximately 770 million in 2013 (Fig. 1) (World Bank in Understanding Poverty 2017). Currently the majority of the world’s poor live in rural areas, and their livelihoods are dominated by land-based activities including gathering of Non-Timber Forest Products (NTFPs). There were rela tively few studies offering more socially orientated perspectives and insights on the links between NTFP use, dependency and poverty. The ordinary people using NTFPs, their reasons for doing so and their experiences are given in this book.
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Rethinking the dialectics of rural and urban in African art and scholarship:
- Authors: Siegenthaler, Fiona , Nzewi, Ugochukwu-Smooth C , Siegert, Nadine
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146022 , vital:38488 , DOI: 10.1080/19301944.2018.1538856
- Description: This issue of Critical Interventions is dedicated to rethinking the dialectics of the rural and the urban in African art and scholarship. Inspired by the general theme of the European Conference of African Studies (ECAS/AEGIS) in Basel (June 28 to July 1, 2017), Urban Africa – Urban Africans: New Encounters of the Rural and the Urban, the guest editors of this issue hosted two panels on the relationship of urban-based artists and their interest in rural topographies, aesthetics, and cultural practices.
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The contribution of NTFPs to rural livelihoods in different agro-ecological zones of South Africa
- Authors: Mugido, Worship , Shackleton, Charlie M
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177488 , vital:42826 , https://doi.org/10.1016/j.forpol.2019.101983
- Description: Although many studies have examined the contributions of non-timber forest products (NTFPs) to rural livelihoods, relatively few consider the context in which income shares are shaped. A core one is the local agro-ecological potential because it moulds possible land use options and the potential balance between agricultural and NTFP activities. Using income surveys of 1200 households, this paper examined the absolute and relative contribution of NTFP income at six sites each paired across a gradient of differing agro-ecological potential.
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The use of turnitin in the higher education sector: Decoding the myth
- Authors: Mphahlele, Amanda , McKenna, Sioux
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124229 , vital:35578 , https://doi.org/10.1080/02602938.2019.1573971
- Description: Plagiarism needs to be addressed to maintain academic standards and to safeguard the integrity of the academic project. With the evolving digital world, conventional methods of addressing plagiarism are gradually being dismissed in favour of new technologies. Unfortunately, there is a general misunderstanding about what such technologies do. This paper was written from a PhD study, and looks at how such misunderstandings emerge across the higher education sector of one country. Institutional policies and other documents related to plagiarism were analysed from public universities across South Africa, and this was then augmented with interviews with members of institutional plagiarism committees. The results of the study revealed that technology is a key facet in these universities’ attempts to reduce the incidents of plagiarism, and that Turnitin is the most favored text-matching tool. However, the software is misunderstood to be predominantly a plagiarism detection tool for policing purposes, ignoring its educational potential for student development. The implication is that, if Turnitin is primarily used as a policing tool, students are not only denied access to nuanced pedagogical interventions that might develop their academic writing, but its misuse could also change students’ behavior in undesirable ways.
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A Flexible Approach for the Application of Immersive Audio to an Installation Performance:
- Authors: Devonport, Sean , Foss, Richard
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426720 , vital:72385 , https://www.isea-international.org/symposia/1988-2022/
- Description: This paper investigates the use of the ImmerGo spatial audio system and Ethernet AVB as a platform for the creation and deployment of immersive audio content. An analysis of Ethernet AVB and ImmerGo’s features is given. This is followed by a practical implementation of ImmerGo within an installation setting of a choreographed performance. This approach provided key features such as user control from a mobile device to render positions of audio tracks and control DAW transport. The Ethernet AVB network allowed for real-time synchronized audio streaming, audio device interoperability, distributed endpoint processing and simple audio routing schemes.
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A missing link in the estuarine nitrogen cycle?: coupled nitrification-denitrification mediated by suspended particulate matter
- Authors: Zhu, Weijing , Wang, Cheng , Hill, Jaclyn M , He, Yangyang , Tao, Bangyi , Mao, Zhihua , Wu, Weixiang
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68368 , vital:29244 , https://0-doi.org.wam.seals.ac.za/10.1038/s41598-018-20688-4
- Description: In estuarine and coastal ecosystems, the majority of previous studies have considered coupled nitrification-denitrification (CND) processes to be exclusively sediment based, with little focus onsuspended particulate matter (SPM) in the water column. Here, we present evidence of CND processes in the water column of Hangzhou Bay, one of the largest macrotidal embayments in the world.
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A preliminary study of minimal-contention locks
- Authors: Machanick, Philip , Mbiyavanga, Mamana
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439093 , vital:73544 , https://doi.org/10.1145/3278681.3278713
- Description: As multicore CPUs become more common, scalable synchronization primitives have wider use and ideas previously used in large-scale computation are worth re-opening for wider use. In this paper I explore one approach to scalable synchronization, a minimal-contention lock (M-lock). The key idea is to avoid spinning on a global variable but instead for each blocked task (process or thread) to spin on a local lock representing the task that immediately preceded it in attempting to acquire the lock. This creates an ordering based on the order in which tasks attempt to acquire the lock, preventing starvation. The only globally shared variable is a pointer to the next local lock to be contended for. Each contending task swaps the value of this pointer for a pointer to its own variable. It spins on the variable previously pointed to by the global pointer. Each waiting task spins on a lock only seen by itself and the owner of that lock variable. While a task is spinning, the lock variable can be held in its local cache until invalidated by the lock owner when it unsets the lock. Consequently, the amount of bus traffic is considerably less than with a spinlock, which has the pernicious feature that the task releasing the lock is delayed by all the other bus traffic arising from contention for the lock. An MCS lock has similar properties but is more complicated and requires more memory contention-causing operations. This paper outlines the design of the M-lock and provides a preliminary performance analysis.
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Avian thermoregulation in the heat: phylogenetic variation among avian orders in evaporative cooling capacity and heat tolerance
- Authors: Smit, Ben , Whitfield, Maxine C , Talbot, William A , Gerson, Alexander R , McKechnie, Andrew E , Wolf, Blair O
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440517 , vital:73789 , https://doi.org/10.1242/jeb.174870
- Description: Little is known about the phylogenetic variation of avian evaporative cooling efficiency and heat tolerance in hot environments. We quantified thermoregulatory responses to high air temperature (Ta) in ∼100-g representatives of three orders, namely, the African cuckoo (Cuculus gularis, Cuculiformes), lilac-breasted roller (Coracias caudatus, Coraciiformes) and Burchell's starling (Lamprotornis australis, Passeriformes). All three species initiated respiratory mechanisms to increase evaporative heat dissipation when body temperature (Tb) approached 41.5°C in response to increasing Ta, with gular flutter observed in cuckoos and panting in rollers and starlings. Resting metabolic rate and evaporative water loss increased by quantitatively similar magnitudes in all three species, although maximum rates of evaporative water loss were proportionately lower in starlings. Evaporative cooling efficiency [defined as the ratio of evaporative heat loss (EHL) to metabolic heat production (MHP)] generally remained below 2.0 in cuckoos and starlings, but reached a maximum of ∼3.5 in rollers. The high value for rollers reveals a very efficient evaporative cooling mechanism, and is similar to EHL/MHP maxima for similarly sized columbids which very effectively dissipate heat via cutaneous evaporation. This unexpected phylogenetic variation among the orders tested in the physiological mechanisms of heat dissipation is an important step toward determining the evolution of heat tolerance traits in desert birds.
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Expanding the SAR of Nontoxic Antiplasmodial Indolyl-3-ethanone Ethers and Thioethers:
- Authors: Lunga, Mayibongwe J , Chisango, Ruramai L , Weyers, Carli , Isaacs, Michelle , Taylor, Dale , Edkins, Adrienne L , Khanye, Setshaba D , Hoppe, Heinrich C , Veale, Clinton G L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164389 , vital:41114 , DOI: 10.1002/cmdc.201800235
- Description: Despite major strides in reducing Plasmodium falciparum infections, this parasite still accounts for roughly half a million annual deaths. This problem is compounded by the decreased efficacy of artemisinin combination therapies. Therefore, the development and optimisation of novel antimalarial chemotypes is critical. In this study, we describe our strategic approach to optimise a class of previously reported antimalarials, resulting in the discovery of 1-(5-chloro-1H-indol-3-yl)-2-[(4-cyanophenyl)thio]ethanone (13) and 1-(5-chloro-1H-indol-3-yl)-2-[(4-nitrophenyl)thio]ethanone (14), whose activity was equipotent to that of chloroquine against the P. falciparum 3D7 strain.
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Exploration and design of a synchronous message passing framework for a CPU-NPU heterogeneous architecture
- Authors: Pennefather, Sean , Bradshaw, Karen L , Irwin, Barry V W
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429537 , vital:72620 , https://ieeexplore.ieee.org/abstract/document/8425384
- Description: In this paper we present the development of a framework for communication between an NPU (network processing unit) and CPU through synchronous message passing that is compliant with the synchronous communication events of the CSP formalisms. This framework is designed to be used for passing generic information between application components operating on both architectures and is intended to operate in conjunction with existing datapaths present on the NPU which in turn are responsible for network traffic transmission. An investigation of different message passing topologies is covered before the proposed message passing fabric is presented. As a proof of concept, an initial implementation of the fabric is developed and tested to determine its viability and correctness. Through testing it is shown that the implemented framework operates as intended. However, it is noted the throughput of the exploratory implementation is not considered suitable for high-performance applications and further evaluation is required.
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Introduction: Blurring Boundaries
- Authors: Mnyaka, Phindezwa , Macleod, Catriona I
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434252 , vital:73042 , ISBN 978-3-319-74720-0 , https://link.springer.com/chapter/10.1007/978-3-319-74721-7_9
- Description: This chapter introduces the section on blurring boundaries in research. The chapters within this section unpack the ethical dilemmas that researchers negotiate when they find themselves stepping outside their roles as researchers in the field. Research encounters presuppose particular boundaries, depending on the methodology employed and the research questions posed. However, participants may identify researchers differently, compelling them to respond in unanticipated ways as possibly therapists, clinicians, interlocutors, and activists. Collectively, the authors of the chapters in this section explore the ethical implications of blurring such boundaries. They unpack the significance of various forms of intimacies that may emerge while undertaking research, how researchers are positioned as agents of social change, and how researchers negotiate their statuses as insiders and outsiders in fieldwork.
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Purification and characterization of an amyloglucosidase from an ericoid mycorrhizal fungus (Leohumicola incrustata)
- Authors: Adeoyo, Olusegun R , Pletschke, Brett I , Dames, Joanna F
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440405 , vital:73780 , https://doi.org/10.1186/s13568-018-0685-1
- Description: This study aimed to purify and characterize amyloglucosidase (AMG) from Leohumicola incrustata. AMG was purified to homogeneity from cell-free culture filtrate of an ERM fungus grown in a modified Melin–Norkrans liquid medium. The molecular mass of the AMG was estimated to be 101 kDa by combining the results of Sephadex G-100 gel filtration, sodium dodecyl sulphate–polyacrylamide gel electrophoresis, and zymography. The Km and kcat values were 0.38 mg mL−1 and 70 s−1, respectively, using soluble starch as a substrate. The enzyme was stable at 45 °C (pH 5.0), retaining over 65% activity after a pre-incubation period of 24 h. The metal inhibition profile of the AMG showed that Mn2+ and Ca2+ enhanced activity, while it was stable to metals ions, except a few (Al3+, Co2+, Hg2+ and Cd2+) that were inhibitory at a concentration higher than 5 mM. Thin layer chromatography revealed that only glucose was produced as the product of starch hydrolysis. The amylase from L. incrustata is a glucoamylase with promising characteristics such as temperature stability over an extended period, high substrate affinity and stability to a range of chemicals. Also, this study reports for the first time the possibility of using some culturable ERM fungi to produce enzymes for the bio-economy.
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Seasonal physiological responses to heat in an alpine range-restricted bird: the Cape Rockjumper (Chaetops frenatus)
- Authors: Oswald, Krista N , Lee, Alan T K , Smit, Ben
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441655 , vital:73904 , https://doi.org/10.1007/s10336-018-1582-8
- Description: Hot, dry summer conditions impose physiological stress on endotherms, yet we have a poor understanding of how endotherms seasonally adjust their costs of thermoregulation under hot conditions. We determined whether seasonal phenotypic plasticity in evaporative cooling capacity at high temperatures explained how the range-restricted Cape Rockjumper (Chaetops frenatus; hereafter ‘Rockjumper’), copes with hot and dry summer temperatures of the temperate mountain peaks of southwest South Africa. We measured evaporative water loss (EWL), resting metabolic rate (RMR), and body temperature at high air temperatures (30–42 °C) of individuals from a wild population of Rockjumpers during winter and summer (n = 11 winter, 4 females, 7 males; n = 10 summer, 6 females, 4 males). We found Rockjumper evaporative cooling in summer imposes higher EWL (i.e. greater water costs) compared to winter, although an accompanying lack of change in RMR resulted in increased summer cooling efficiency. These patterns are similar to those observed in species that inhabit regions where summer temperatures are routinely high but the species are not water stressed. Our findings indicate that avian seasonal physiological adjustments to heat can be diverse. Further seasonal studies on thermoregulation in response to heat will greatly improve our knowledge of the functional value of traits such as evaporative cooling efficiency and heat tolerance and how they contribute to the physiological stress organisms experience in heterogenous environments.
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When an Editor Decides to Listen to a City: Heather Robertson, The Herald, and Nelson Mandela Bay
- Authors: Garman, Anthea , Malila, Vanessa
- Date: 2018
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/158427 , vital:40185 , ISBN 9781351664363
- Description: This book provides case studies, many incorporating in-depth interviews and surveys of journalists. It examines issues such as journalists’ attitudes toward their contributions to society; the impact of industry and technological changes; culture and minority issues in the newsroom and profession; the impact of censorship and self-censorship; and coping with psychological pressures and physical safety dilemmas. Its chapters also highlight journalists’ challenges in national and multinational contexts. International scholars, conducting research within a wide range of authoritarian, semi-democratic, and democratic systems, contributed to this examination of journalistic practices in the Arab World, Australia, Bangladesh, Bulgaria, China, Denmark, India, Kenya, Kyrgyzstan, Malaysia, Mexico, Russia, Samoa, South Africa, Taiwan, Turkey, and the United States.
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