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Age and growth of the Cape knifejaw Oplegnathus conwayi, an endemic South African teleost

- Foster, Ryan M, Childs, Amber-Robyn, Mann, Bruce Q, Potts, Warren M

Authors: Foster, Ryan M , Childs, Amber-Robyn , Mann, Bruce Q , Potts, Warren M
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/443128 , vital:74080 , https://doi.org/10.1080/15627020.2022.2035254
Description: The South African spearfishery targets a variety of data-deficient species, which are consequently poorly managed. This study aimed to describe the age and growth of one of these species, the Cape knifejaw, Oplegnathus conwayi, which is endemic to the southern and eastern coasts of South Africa. Monthly biological samples were collected through research spearfishing (n = 170) and augmented by recreational spearfishers’ catches (n = 135). The results indicated that the O. conwayi population sex ratio was skewed towards males (1M:0.6F). The length- and age-frequency distributions were similar between sexes. Oplegnathus conwayi is a relatively slow-growing species, with a maximum-recorded age of 27 years. No significant differences were observed between male and female growth, with the overall population growth curve being best described as L(t) = 697.15(1 − e−0.06(t−6.30)). The slow growth observed in this species is characteristic of a species that is vulnerable to overexploitation, and accordingly a precautionary approach to future management is recommended.
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Date Issued: 2022

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Alignment, scaling and resourcing of citizen-based water quality monitoring Initiatives

- Lotz-Sisitka, Heila, Ward, Mike, Taylor, Jim, Vallabh, Priya, Madiba, Morakane, Graham, P Mark, Louw, Adrienne J, Brownell, Faye

Authors: Lotz-Sisitka, Heila , Ward, Mike , Taylor, Jim , Vallabh, Priya , Madiba, Morakane , Graham, P Mark , Louw, Adrienne J , Brownell, Faye
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , report
Identifier: http://hdl.handle.net/10962/435729 , vital:73195 , ISBN 978-0-6392-0344-7 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2854%20final.pdf
Description: This action-oriented research project seeks to address the policy-practice contradiction that exists between commit-ments and requirements for citizen engagement and in-volvement in Integrated Water Quality Management (IWQM) and a lack of sustainable support for scaling high quality Citi-zen-based Water Quality Monitoring (CBWQM) practices that exist in South Africa.
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Date Issued: 2022

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AMADAR: a python-based package for large scale prediction of Diels–Alder transition state geometries and IRC path analysis

- Isamura, Bienfait K, Lobb, Kevin A

Authors: Isamura, Bienfait K , Lobb, Kevin A
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/453143 , vital:75226 , xlink:href="https://link.springer.com/article/10.1186/s13321-022-00618-3"
Description: Predicting transition state geometries is one of the most challenging tasks in computational chemistry, which often requires expert-based knowledge and permanent human intervention. This short communication reports technical details and preliminary results of a python-based tool (AMADAR) designed to generate any Diels–Alder (DA) transition state geometry (TS) and analyze determined IRC paths in a (quasi-)automated fashion, given the product SMILES. Two modules of the package are devoted to performing, from IRC paths, reaction force analyses (RFA) and atomic (fragment) decompositions of the reaction force F and reaction force constant κ. The performance of the protocol has been assessed using a dataset of 2000 DA cycloadducts retrieved from the ZINC database. The sequential location of the corresponding TSs was achieved with a success rate of 95%. RFA plots confrmed the reaction force constant κ to be a good indicator of the (non)synchronicity of the associated DA reactions. Moreover, the atomic decomposition of κ allows for the rationalization of the (a)synchronicity of each DA reaction in terms of contributions stemming from pairs of interacting atoms. The source code of the AMADAR tool is available on GitHub [CMCDD/AMADAR(github. com)] and can be used directly with minor customizations, mostly regarding the local working environment of the user.
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Date Issued: 2022

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AMANZI For Food

- Lotz-Sisitka, Heila, Pesanayi, Tichaona, Sisitka, Lawrence, Metelerkamp, Luke, Chakona, Gamuchirai, van Staden, Wilma, Durr, Sarah, Matiwane, Mandelive, Maqwelane, Lwanda, Conde-Aller, Laura, Shawarire, Patience

Authors: Lotz-Sisitka, Heila , Pesanayi, Tichaona , Sisitka, Lawrence , Metelerkamp, Luke , Chakona, Gamuchirai , van Staden, Wilma , Durr, Sarah , Matiwane, Mandelive , Maqwelane, Lwanda , Conde-Aller, Laura , Shawarire, Patience
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , report
Identifier: http://hdl.handle.net/10962/435745 , vital:73197 , ISBN 978-0-6392-0309-6 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/TT 868 final web.pdf
Description: This action-oriented research project seeks to address the policy-practice contradiction that exists between commit-ments and requirements for citizen engagement and in-volvement in Integrated Water Quality Management (IWQM) and a lack of sustainable support for scaling high quality Citi-zen-based Water Quality Monitoring (CBWQM) practices that exist in South Africa.
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Date Issued: 2022

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An assessment of the medium-term reproductive success of an extralimital white rhinoceros population

- Truter, Anja, Mgqatsa, Nokubonga, Parker, Daniel M

Authors: Truter, Anja , Mgqatsa, Nokubonga , Parker, Daniel M
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/462570 , vital:76315 , xlink:href="https://doi.org/10.1080/15627020.2022.2132120"
Description: The white rhinoceros (Ceratotherium simum) is threatened primarily due to continued poaching for its horns. In South Africa, partly to promote the conservation of the species, white rhinos have been introduced into areas where they did not occur historically (i.e. where they are considered extralimital). Few studies have investigated the conservation contribution of extralimital white rhinos to the overall national herd. We aimed to determine whether the white rhinos introduced to a private game reserve in the Eastern Cape province have been successful from a reproductive perspective. We calculated inter-calving intervals, age at first calving, sex ratios of calves, and recruitment rates for white rhinos at a single site between 1992 and 2019. The average net annual population growth rate for the population was 10%, which is higher than the recommended 5% by the Biodiversity Management Plan for white rhinos. Trends in density-dependent parameters such as age at first calving and inter-calving intervals also indicated that the study population is still well below the density at which ecological constraints may manifest. We demonstrate that an extralimital white rhino population in the Eastern Cape can be successful from a reproductive perspective.
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Date Issued: 2022

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An evaluation of hand-based algorithms for sign language recognition

- Marais, Marc, Brown, Dane L, Connan, James, Boby, Alden

Authors: Marais, Marc , Brown, Dane L , Connan, James , Boby, Alden
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/465124 , vital:76575 , xlink:href="https://ieeexplore.ieee.org/abstract/document/9856310"
Description: Sign language recognition is an evolving research field in computer vision, assisting communication between hearing disabled people. Hand gestures contain the majority of the information when signing. Focusing on feature extraction methods to obtain the information stored in hand data in sign language recognition may improve classification accuracy. Pose estimation is a popular method for extracting body and hand landmarks. We implement and compare different feature extraction and segmentation algorithms, focusing on the hands only on the LSA64 dataset. To extract hand landmark coordinates, MediaPipe Holistic is implemented on the sign images. Classification is performed using poplar CNN architectures, namely ResNet and a Pruned VGG network. A separate 1D-CNN is utilised to classify hand landmark coordinates extracted using MediaPipe. The best performance was achieved on the unprocessed raw images using a Pruned VGG network with an accuracy of 95.50%. However, the more computationally efficient model using the hand landmark data and 1D-CNN for classification achieved an accuracy of 94.91%.
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Date Issued: 2022

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Analysing the Impact of Extended Curriculum Programmes: Implications for Theory, Design and Practice

- Boughey, Chrissie

Authors: Boughey, Chrissie
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , book chapter
Identifier: http://hdl.handle.net/10962/434453 , vital:73063 , ISBN 9781991201737 , https://africansunmedia.store.it.si/ZA/book/extended-curriculum-programmes-challenges-and-opportunities/1199327
Description: The introduction of ECPs in South African Universities is seen by many as South Africa’s key strategy for addressing the problem of poor patterns of student success and has its basis on the uncontested acceptance that an extended study duration may be necessary to bring some categories of learners to a level of parity with the readiness expectations of their course of study. Even so, this transformative strategic imperative has been plagued by a range of challenges that include poor systems readiness; poor selection mechanisms in the identification of ECP students; poor numeracy and literacy amongst students, and indifferent teacher involvement in ECPs. This volume offers a rare insight into many of the above-recognised challenges and in so doing provides critical matter for thought for educators within the higher education sector.
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Date Issued: 2022

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Application of gold and palladium nanoparticles supported on polymelamine microspheres in the oxidation of 1-phenylethanol and some other phenyl substituted alcohols

- Storm, Ené, Maggott, Emile D, Mashazi, Philani N, Nyokong, Tebello, Malgas-Enus, Rehana, Mapolie, Selwyn F

Authors: Storm, Ené , Maggott, Emile D , Mashazi, Philani N , Nyokong, Tebello , Malgas-Enus, Rehana , Mapolie, Selwyn F
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/299824 , vital:57858 , xlink:href="https://doi.org/10.1016/j.mcat.2022.112456"
Description: Melamine formaldehyde and melamine resorcinol formaldehyde microspheres were decorated with Au and Pd nanoparticles and applied as heterogeneous catalysts in the oxidation of 1-phenylethanol. The catalysts showed similar activities irrespective of the support employed. Moderate conversion activities of 48–50% were achieved when using acetonitrile as solvent; however, when employing water as solvent, the supported catalysts formed a three-phase, emulsion system which facilitated the catalytic conversion of 1-phenylethanol to acetophenone at much higher conversions of around 83%. The oxidant, TBHP, decomposed rapidly in acetonitrile, whilst it remained stable in aqueous solution, leading to the enhanced activities observed when using water as solvent. These systems also proved to be recyclable for up to five cycles, with only slight loss of activity observed; this can be attributed to the physical loss of catalyst during the workup procedure conducted between each cycle.
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Date Issued: 2022

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Aptamer versus antibody as probes for the impedimetric biosensor for human epidermal growth factor receptor

- Centane, Sixolile, Nyokong, Tebello

Authors: Centane, Sixolile , Nyokong, Tebello
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/229884 , vital:49720 , xlink:href="https://doi.org/10.1016/j.jinorgbio.2022.111764"
Description: In the present work, the performance of aptamer and antibody bioreceptors for the detection of the human epidermal growth factor receptor (HER2) cancer biomarker on a glassy carbon electrode is reported. The carboxylic acid group rich graphene quantum dots (GQDs) modified with gold nanoparticles and a porphyrin binuclear framework (CoP-BNF) were used to modify the glassy carbon electrode. The aptamer and antibody were both amine functionalized and attached to GQDs and CoP-BNF through an amide bond. The designed immunosensors and aptasensors in this work were characterized using electrochemical impedance spectroscopy. The aptasensors, compared to the immunosensors gave better limit of detection values. The aptasensor outperforms the immunosensor in terms of its reusability and storability, while the immunosensor could not be regenerated for subsequent experiments. The potential applicability of all sensors in this work was also investigated, by detection of HER2 in spiked human serum with acceptable results.
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Date Issued: 2022

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Artisanal mining versus sustainability of agricultural food supply chains: effects of the conflicts in Southern Zimbabwe

- Chari, Felix, Novukela, Cawe, Ngcamu , Bethuel Sibongiseni

Authors: Chari, Felix , Novukela, Cawe , Ngcamu , Bethuel Sibongiseni
Date: 2022
Subjects: Traditional farming Small Scale mining Great Zimbabwe Article
Language: English
Type: text , article
Identifier: http://hdl.handle.net/11260/7082 , vital:52810 , xlink:href="https://doi.org/10.1080/23311886.2021.2002542"
Description: This article seeks to establish the social and environmental consequences of artisanal mining on economic sustainability of agricultural food supply chains in Zimbabwe. Following a descriptive research design, interviews were conducted with 36 farmers. Interviewees were purposively sampled from potential respondents in Southern Zimbabwe. Interview results were triangulated with data from published reports and newspaper articles. Data was analysed using NVivo application version 12 and presented in vignettes. The results of this study are useful to artisanal miners, farmers, and government. Recommendations for further studies are given. KEYWORDS: Artisanal mining farmers food supply chains Zimbabwe sustainability
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Date Issued: 2022

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Assessing climate risk to support urban forests in a changing climate

- Esperon-Rodriguez, Manuel, Rymer, Paul D, Power, Sally A, Barton, David N, Cariñanos, Paloma, Dobbs, Cynnamon, Eleuterio, Ana A, Escobedo, Francisco J, Hauer, Richard, Hermy, Martin, Jahani, Ali, Onyekwelu, Jonathan C, Östberg, Johan, Pataki, Diane, Randrup, Thomas B, Rasmussen, Tørres, Roman, Lara A, Russo, Alessio, Shackleton, Charlie M, Solfjeld, Ingjerd, Van Doorn, Natalie S, Wells, Matthew J, Wiström, Björn, Yan, Pengbo, Yang, Jun, Tjoelker, Mark G

Authors: Esperon-Rodriguez, Manuel , Rymer, Paul D , Power, Sally A , Barton, David N , Cariñanos, Paloma , Dobbs, Cynnamon , Eleuterio, Ana A , Escobedo, Francisco J , Hauer, Richard , Hermy, Martin , Jahani, Ali , Onyekwelu, Jonathan C , Östberg, Johan , Pataki, Diane , Randrup, Thomas B , Rasmussen, Tørres , Roman, Lara A , Russo, Alessio , Shackleton, Charlie M , Solfjeld, Ingjerd , Van Doorn, Natalie S , Wells, Matthew J , Wiström, Björn , Yan, Pengbo , Yang, Jun , Tjoelker, Mark G
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/402191 , vital:69829 , xlink:href="https://doi.org/10.1002/ppp3.10240"
Description: Globally, cities are planning for resilience through urban greening initiatives as governments understand the importance of urban forests in improving quality of life and mitigating climate change. However, the persistence of urban forests and the ecosystem benefits they provide are threatened by climate change, and systematic assessments of causes of tree dieback and mortality in urban environments are rare. Long-term monitoring studies and adaptive management are needed to identify and prevent climate change-driven failures and mortality. Research and monitoring when coupled with systematic forecasting will enable governments to incorporate climate change resilience into urban forestry planning. Future scenarios in which urban forests are resilient or in decline will depend on the management and planning actions we make today.
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Date Issued: 2022

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Assessing the electrocatalytic activity of a localized push-pull system in cobalt phthalocyanine/graphene quantum dot hybrids

- Nkhahle, Reitumetse, Nyokong, Tebello

Authors: Nkhahle, Reitumetse , Nyokong, Tebello
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/229909 , vital:49722 , xlink:href="https://doi.org/10.1016/j.matchemphys.2022.125842"
Description: In this study, two cobalt phthalocyanines (asymmetric complex 1) and symmetric (complex 2) were synthesized and conjugated to nitrogen-doped graphene quantum dots (NGQDs) through covalent and non-covalent means to create Co phthalocyanine (CoPc)-NGQDs hybrid systems. The CoPcs and conjugates were applied as electrode modifiers on a glassy carbon electrode in the electrochemical sensing of nitrite. Of the CoPcs alone, complex 1 performed better than complex 2 regarding the limits of detection (LoD) recorded (5.74 μM for 1 and 15.1 μM for 2). Regarding the conjugates/nanocomposites, the π-π stacked conjugate derived from complex 2 (2πNGQDs) demonstrated highly favourable electrochemical potential with an LoD value of 0.70 μM. The nanocomposites fashioned from complex 1 were marred by a reduced loading which rendered the conjugates poor electrochemical sensors. These observations however do not disqualify GQDs as complementary nanomaterials to phthalocyanines but rather shed light on seeking alternative routes to increasing the Pc loading in conjugates (more so in π-π stacked conjugates).
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Date Issued: 2022

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Assessing the Impact of DNS Configuration on Low Bandwidth Networks

- Okuthe, J A, Terzoli, Alfredo

Authors: Okuthe, J A , Terzoli, Alfredo
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/430903 , vital:72726 , https://doi.org/10.1007/978-3-031-34896-9_6
Description: Domain name system (DNS) is an essential enabler for connecting us-ers and services on the Internet. DNS translates human readable do-main names into IP addresses and precedes client connection to a server via a domain name. DNS service is therefore expected to con-sume network bandwidth even though it offers no direct benefit to the user. Having observed the large component of DNS traffic on the com-munity network local loop in our previous study, we migrated the DNS service from a server on the LAN to the gateway router and reconfig-ured the cache time-to-live. Results from the analysis of network traffic captured from the gateway router interface show a 26% decrease in the downlink bandwidth utilization and 46% decline in the uplink bandwidth utilization. The DNS component of the local loop traffic reduces from 45.28% to 4.11%. On the other hand, the Web component of the local loop traffic increases from 49.42% to 95.49%. Data collected from a mirroring port on the LAN switch indicate a decrease in the DNS portion of the internal traffic from 0.38% to 0.18%. Although the DNS reconfigu-ration helps alleviate network bandwidth constraints and reduces DNS component of the traffic, the Web portion increases. The implementa-tion of effective, efficient and sustainable Web traffic management is therefore required.
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Date Issued: 2022

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Asymmetrical zinc (II) phthalocyanines conjugated to metal tungstate nanoparticles for photoinactivation of Staphylococcus aureus

- Mgidlana, Sithi, Managa, Muthumuni, Nyokong, Tebello

Authors: Mgidlana, Sithi , Managa, Muthumuni , Nyokong, Tebello
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/295718 , vital:57372 , xlink:href="https://doi.org/10.1080/00958972.2022.2090837"
Description: In this study, we report for the first time on the photodynamic antimicrobial chemotherapy (PACT) of asymmetrical zinc(II) phthalocyanines and their conjugates with nickel tungstate (NiWO4), cobalt tungstate (CoWO4) and bismuth tungstate (Bi2WO6) nanoparticles. CoWO4, NiWO4 and Bi2WO6 were capped with glutathione and covalently linked to three asymmetrical zinc(II) phthalocyanines for PACT. The plate count method was used to investigate the effect of covalently linking asymmetrical zinc(II) phthalocyanines to nanoparticles under light (for PACT against Staphylococcus aureus) and in the dark. Both Pc complexes and the conjugates indicated minimum dark-toxicity. The conjugates showed greater antimicrobial activity against a gram-positive and drug resistant bacteria, Staphylococcus aureus, than Pc complexes alone.
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Date Issued: 2022

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