Metrological framework for selecting morphological characters to identify species and estimate developmental maturity of forensically significant insect specimens
- Authors: Midgley, John M , Villet, Martin H
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440784 , vital:73813 , https://doi.org/10.1080/20961790.2020.1794347
- Description: Accurate age estimates of immature necrophagous insects associated with a human or animal body can provide evidence of how long the body has been dead. These estimates are based on species-specific details of the insects’ aging processes, and therefore require accurate species identification and developmental stage estimation. Many professionals who produce or use identified organisms as forensic evidence have little training in taxonomy or metrology, and appreciate the availability of formalized principles and standards for biological identification. Taxonomic identifications are usually most readily and economically made using categorical and qualitative morphological characters, but it may be necessary to use less convenient and potentially more ambiguous characters that are continuous and quantitative if two candidate species are closely related, or if identifying developmental stages within a species. Characters should be selected by criteria such as taxonomic specificity and metrological repeatability and relative error. We propose such a hierarchical framework, critique various measurements of immature insects, and suggest some standard approaches to determine the reliability of organismal identifications and measurements in estimating postmortem intervals. Relevant criteria for good characters include high repeatability (including low scope for ambiguity or parallax effects), pronounced discreteness, and small relative error in measurements. These same principles apply to individuation of unique objects in general.
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Mobile attendance based on face detection and recognition using OpenVINO
- Authors: Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465201 , vital:76582 , xlink:href="https://ieeexplore.ieee.org/abstract/document/9395836"
- Description: The OpenVINO toolkit enables versatile computer vision with an Intel® Movidius ™ Neural Compute Stick 2 connected to a Raspberry Pi. This small portable platform provides new opportunities for innovative solutions in computer vision applications and beyond. This paper investigates its feasibility for mobile attendance systems for settings such as classrooms or other scenarios that require headcount or roll call. Related studies of face-based systems are explored, while the advantages of the proposed system are highlighted. Although there are some positioning constraints, the proof-of-concept system processes an approximate average of five faces per second. That means it can take attendance in a lecture room of 90 students in about 18 seconds. A recognition accuracy of 98.1% with an f-score of 96.9% was yielded on a private classroom dataset captured with a modest RPi camera. These promising results were achieved using a tiny ResNet-18 architecture, producing significantly better results than MobileNet. Furthermore, it outperformed the recognition accuracy of other ‘lightweight’ methods used in the literature that do not run off embedded devices on publicly available datasets.
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Modulation of the optical properties of chiral porphyrin dimers by introducing bridged chiral amide-bonds
- Authors: Qin, Mingfeng , Zhang, Zhen , Zhu, Weihua , Mack, John , Soy, Rodah C , Nyokong, Tebello , Liang, Xu
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190815 , vital:45031 , xlink:href="https://doi.org/10.1142/S1088424620500492"
- Description: The d/l-enantiomers of a series of three Zn(II)tetraarylporphyrin dimers were synthesized and isolated by incorporating a bridging amide-bonded xanthene moiety at the para-position of one of the meso-aryl rings. The electronic structures and optical properties were modulated by incorporating chiral amino acid moieties into the amide-bonding moieties of the xanthene bridge that contain methyl, tolyl and 2-methylindole substituents. A cofacial dimer was formed in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) resulting in a significant red shift of the B band, due to a relative destabilization of the HOMO, which has large MO coefficients on the pyrrole nitrogens. The sign sequences observed in the B band region of the CD spectra due to the presence of the chiral amino acid moieties were modified due to this change in geometry. Significant CD intensity is also observed in the B band region of the CD spectra of anion radical species during in situ spectroelectrochemical measurements.
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Monetary Policy Credibility and Inflation Expectations: Exploring an unconventional channel in South Africa
- Authors: Bom, Abongile S , Khumalo, Sibanisezwe A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/470644 , vital:77381 , https://hdl.handle.net/10520/ejc-aa_ajber_v16_n3_a15
- Description: Conventional monetary policies have been tested by the various shocks that have recently affected the globe. As a result, the effectiveness of traditional tools in dealing with contemporary shocks have been questioned in recent literature. In South Africa, relatively high inflation levels and sluggish growth rates when compared to other emerging economies have made it difficult for the South African Reserve Bank (SARB) to maintain credibility through its monetary policies. This study ascertained if a forward guidance unconventional monetary policy measure is one way to help regain monetary policy credibility. Using the ARDL technique, the study assessed whether the monetary policy credibility level altered the economic agents' views on inflation expectations within South Africa in the short run and long run. The study found that asymmetric credibility at a threshold of 5.5% lowered inflation expectations.
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Morton Feldman-Morton Feldman, Morton Feldman Piano. Philip Thomas
- Authors: Fourie, William
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/484405 , vital:78903 , xlink:href="https://doi.org/10.1017/S0040298220000741"
- Description: ‘The scale of what is actually being represented, whether it be of the whole or of the part, is a phenomenon unto itself.’ Feldman’s words from his famous 1981 essay, ‘Crippled Symmetry’, echoed in my ears as I sat down to listen to Philip Thomas’s monumental new record of the composer’s piano music. It spans over four decades of the composer’s singular creative engagement with the instrument and has a total run-time of nearly six hours. The five-disc box set also contains a rich 52-page essay on Feldman’s piano music, which broaches a wide range of issues ranging from abstract, interpretative ideas regarding touch and decay to more practical discussions around notation.
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Muco-adhesive clarithromycin-loaded nanostructured lipid carriers for ocular delivery: Formulation, characterization, cytotoxicity and stability
- Authors: Makoni, Pedzisai A , Khamanga, Sandile M , Walker, Roderick B
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183150 , vital:43916 , xlink:href="https://doi.org/10.1016/j.jddst.2020.102171"
- Description: Topical ophthalmic formulations are the preferred approach to treat the anterior segment of the eye as it is a non-invasive therapeutic approach. The ocular bioavailability of drugs is generally limited, due to the presence of impervious anatomical barriers and low residence time and contact with the target tissue. Optimization of clarithromycin-loaded nanostructured lipid carriers using Design of Experiments was undertaken. Manufacture of nanostructured lipid carriers was achieved using hot emulsification ultrasonication. Formulation and process parameters were successfully identified following screening and subsequently optimized using Tween® 20, as a stabilizer. Muco-adhesive properties that could potentially increase ocular residence time, in vitro clarithromycin release and cytotoxicity against HeLa cells were evaluated. Short term stability studies of the optimized lipidic formulations was assessed at 4 °C and 22 °C. The optimized formulation exhibited muco-adhesive properties under stationary conditions assessed using Laser Doppler Anemometry, sustained release of API over 24 h under in vitro conditions. In vitro cytotoxicity studies revealed that the NLC were less cytotoxic to HeLa cells in comparison to pure API. The results suggest that the optimized carriers may have the potential to enhance precorneal retention, increase ocular availability and permit dose reduction or permit use of a longer dosing frequency.
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Naked Eye and Colorimetric Detection of Cyanide with a 1, 3‐Diethyl‐2‐thiobarbituric Acid Substituted Ferrocene Chemosensor
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190567 , vital:45006 , xlink:href="https://doi.org/10.1002/slct.202100163"
- Description: A 1,3-diethyl-2-thiobarbituric-acid-substituted ferrocene (FET) has been evaluated for its cyanide sensing ability by UV-visible absorption spectroscopy and other characterization methods. FET provides a ratiometric colorimetric chemosensor for the CN− anion detection in 1 : 1 DMSO/H2O (v/v) solution. The addition of CN− results in an immediate color change from dark blue to pale orange that is visible to the naked eye. Mechanism studies and molecular modelling with TD-DFT calculations demonstrate that nucleophilic addition of CN− to an electrophilic sp2-hybridized carbon atom blocks charge transfer from the ferrocene ring complex to the thiobarbituric acid moiety. The FET sensor exhibits excellent selectivity for CN− and a limit of detection of 0.2 μM.
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Nano Co-Crystal Embedded Stimuli-Responsive Hydrogels: A Potential Approach to Treat HIV/AIDS
- Authors: Witika, Bwalya A , Stander, Jessé-Clint , Smith, Vincent J , Walker, Roderick B
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183137 , vital:43915 , xlink:href="https://doi.org/10.3390/pharmaceutics13020127"
- Description: Currently, the human immunodeficiency virus (HIV) that causes acquired immunodeficiency syndrome (AIDS) can only be treated successfully, using combination antiretroviral (ARV) therapy. Lamivudine (3TC) and zidovudine (AZT), two compounds used for the treatment of HIV and prevention of disease progression to AIDS are used in such combinations. Successful therapy with 3TC and AZT requires frequent dosing that may lead to reduced adherence, resistance and consequently treatment failure. Improved toxicity profiles of 3TC and AZT were observed when combined as a nano co-crystal (NCC). The use of stimuli-responsive delivery systems provides an opportunity to overcome the challenge of frequent dosing, by controlling and/or sustaining delivery of drugs. Preliminary studies undertaken to identify a suitable composition for a stimulus-responsive in situ forming hydrogel carrier for 3TC-AZT NCC were conducted, and the gelation and erosion time were determined. A 25% w/w Pluronic® F-127 thermoresponsive hydrogel was identified as a suitable carrier as it exhibited a gelation time of 5 min and an erosion time of 7 days. NCC-loaded hydrogels were evaluated using in vitro dissolution and cytotoxicity assays. In vitro dissolution undertaken using membrane-less diffusion over 168 h revealed that 3TC and AZT release from NCC-loaded hydrogels was complete and followed zero-order kinetic processes, whereas those loaded with the micro co-crystal and physical mixture were incomplete and best described using the Korsmeyer–Peppas kinetic model. The release of AZT and 3TC from the physical mixture and MCC-loaded gel exhibited a value for n of 0.595 for AZT release from the physical mixture and 0.540 for the MCC technology, whereas the release exponent for 3TC was 0.513 for the physical mixture and 0.557 for the MCC technology indicating that diffusion and erosion controlled 3TC and AZT release. In vitro cytotoxicity assay data revealed that the addition of NCC to the thermoresponsive hydrogel resulted in an improved cell viability of 88.0% ± 5.0% when compared to the cell viability of the NCC of 76.9% ± 5.0%. The results suggest that the use of a thermoresponsive nanosuspension may have the potential to be delivered as an intramuscular injection that can subsequently increase bioavailability and permit dose reduction and/or permit use of a longer dosing frequency.
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Nanohybrid electrocatalyst based on cobalt phthalocyanine-carbon nanotube-reduced graphene oxide for ultrasensitive detection of glucose in human saliva
- Authors: Adeniyi, Omotayo , Nwahara, Nnamdi , Mwanza, Daniel , Nyokong, Tebello , Mashazi, Philani N
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231356 , vital:49880 , xlink:href="https://doi.org/10.1016/j.snb.2021.130723"
- Description: The current diabetes management systems require collecting blood samples via an invasive and painful finger pricking leading to the formation of callus, scarring and loss of sensibility to patients due to continuous monitoring. Therefore, a non-invasive and painless method of determining glucose levels would be desirable to diabetes patients who need constant monitoring. Saliva glucose measurement is a non-invasive alternative for diabetes management. A highly sensitive, stable, and selective non-enzymatic electrochemical sensor that can accurately quantify saliva glucose is required. A single-walled carbon nanotube/reduced graphene oxide/cobalt phthalocyanines nanohybrid modified glassy carbon electrode (GCE-SWCNT/rGO/CoPc) has been fabricated for the non-enzymatic determination of glucose in human saliva. The SWCNT/rGO/CoPc was characterized using various spectroscopic, microscopic, and electrochemical techniques. The synergistic effect between SWCNT, rGO, and CoPc facilitated excellent electron transfer process that improved the sensor sensitivity. The GCE-SWCNT/rGO/CoPc sensor exhibited two linear responses in the 0.30 μM to 0.50 mM and 0.50–5.0 mM glucose concentration ranges, and the detection limit was 0.12 μM. The sensor had an excellent saliva glucose detection sensitivity of 992.4 μA·mM−1·cm−2 and high specificity for glucose in the presence of other coexisting analytes. In addition, it showed good storage stability, reusability, and a fast response time of about 1.2 s. The GCE-SWCNT/rGO/CoPc nanohybrid electrode showed excellent potential for developing accurate, non-invasive, and painless glucose sensing.
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Nationwide Assessment of Population Structure, Stability and Plant Morphology of Two Mimusops Species along a Social-Ecological Gradient in Benin, West Africa
- Authors: Sinasson Sanni, Giséle K , Shackleton, Charlie M , Sinsin, Brice
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399805 , vital:69560 , xlink:href="https://doi.org/10.3390/f12111575"
- Description: Understanding tree species autecology and population structure supports effective conservation actions. Of particular importance are multipurpose trees that provide non-timber forest products (NTFPs). We assessed the population structures and morphologies of two species of NTFP trees in the genus Mimusops across bioclimatic zones in Benin by sampling 288 plots within 11 forests. Structural characteristics were compared between species, forests and zones. Correlations were also observed between Mimusops tree regeneration density, tree features and ecological characteristics. The density of trees ≥5 cm and of regeneration and mean tree height were higher for M. andongensis (within more protected forest) than M. kummel (in forests with access to people), while the highest mean diameter was observed for M. kummel. Tree and regeneration densities and mean height were greatest in the humid zone of Benin, whilst the largest mean diameter was obtained in the sub-humid zone. The results showed significant correlations between regeneration density and soil properties for M. andongensis but not for M. kummel. The correlations between tree morphology and soil characteristics were weak for both species. Ecological characteristics, along with the species’ functional traits and pressures, are important factors related to the observed differences between the species. All diameter classes were represented, and the population seemed more stable in the more protected forest relative to other forests. Mimusops trees with a diameter of 5–15 cm represented more than 30% of this species in most forests; this suggests, for M. kummel, whose trees flower when quite small (≥6 cm dbh), that there are sufficient reproductive trees. Thus, as a long-lived species, its populations could be maintained even with low/episodic recruitment. However, we found no regeneration in many forests and climate change could threaten populations. Therefore, it is important to investigate regeneration growth and dynamics, seed production and germination of the species in relation to the biophysical conditions and disturbances experienced by Mimusops stands.
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Nature-Based Solutions for Coastal Engineering and Management
- Authors: Slinger, Jill , Stive, Marcel , Luijendijk, Arjen
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177521 , vital:42829 , https://doi.org/10.3390/w13070976
- Description: There is a growing scientific and engineering interest in exploring how natural processes can provide management solutions to resolve the degradation and vulnerability of coastal environments. Climate change and associated sea level rise together with drivers, such as subsidence, reduced sediment supply and coastal squeeze represent major risk factors for coastal systems sustainability. Using natural processes to deal with these risk factors presents a nontrivial challenge. This special issue focuses on nature-based solutions and state-of-the-art interventions in the coastal environment.
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New insights into the geographical distribution, ecology and conservation status of South Africa’s endemic Coastal Leaf-toed Gecko, Cryptactites peringueyi (Boulenger, 1910)
- Authors: Nicolau, Gary K , Petford, Melissa , Edwards, Shelley , Busschau, Theo , Lynch, Kier , Kemp, Luke , Balmer, Jonathan P , Keates, Chad , Hundermark, Courtney R , Weeber, Joshua , Conradie, Werner C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/461517 , vital:76209 , xlink:href="https://www.biotaxa.org/hn/article/view/63908"
- Description: Range-restricted species are generally poorly known and at higher risk of extinction than species with wider distributions. In the past, the Coastal Leaf-toed Gecko, Cryptactites peringueyi (Boulenger, 1910) caused much confusion and was once referred to as “one of the herpetological mysteries of the region”. Knowledge on the species has grown substantially, predominately due to new insights into its ecological preferences. Surveys from 2018 through early 2020 re-established the presence of C. peringueyi at three of four historical localities, as well as documenting four new localities. In 2018, preliminary data from these surveys resulted in an IUCN Red List downgrading from Critically Endangered to Near Threatened. However, with further investigation into the distribution of the species, the results from the present study more than doubled the previously estimated Extent of Occurrence from 785 km2 to 1504 km2 and the populations appear to be stable, despite environmental and anthropogenic disturbance. By incorporating environmental niche modelling, we further discuss the distribution, habits and ecology of C. peringueyi. The results presented here highlight the importance of fully understanding a species’ ecology to address its conservation status and we suggest that a new listing of Least Concern is appropriate for C. peringueyi.
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News for action: a critical case study of Yes! magazine
- Authors: Hosford-Israel, Carly
- Date: 2021
- Subjects: Yes! (Bainbridge Island, WA) , Magazines -- United States -- History and criticism , Journalistic ethics , Journalism -- Social aspects -- United States , Journalism -- Objectivity , Mass media -- Ownership -- United STates , Publishers and publishing -- United States
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/170822 , vital:41963
- Description: Coming out of more than a century of concern over the commercialization and monopolization of media ownership, this study highlights some areas of opportunity for alternative media in the United States. Holding an ideal of participatory democracy, driven by an educated electorate, the research considers an example of US media action, Ye s ! magazine, from the perspective of alternative media and social movement theories. As alternative media are most generally a response to the mainstream model which acts in the interests of profit rather than public participation in politics, this thesis will cover not only democratic responsibility, but also mainstream media ownership and organization when considering the current manifestation of Ye s ! magazine. Inspired by a frustration with the concentration of mainstream media ownership, and consequently journalistic homogenization, this research explores opportunities for democratic media divergence and contestation. After 18 years of publication, Ye s ! was chosen as an ideal candidate for research due to its sustainability and longevity as one such critical media organization. Through in-depth interviews with Yes! personnel, and ideological analysis of Yes! articles, the following case study research explores the complexities that construct Ye s ! magazine, a corporately independent publication from Bainbridge Island, Washington.
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No size fits all: Design considerations for networked professional development in higher education
- Authors: Pallitt, Nicola , Gachago, Daniela , Bali, Maha
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/453520 , vital:75260 , ISBN 978-3-030-85241-2 , https://doi.org/10.1007/978-3-030-85241-2_4
- Description: This chapter develops a framework for design considerations that can be used to analyze, contrast, and design networked professional development (NPD) in higher education (HE) contexts. The framework was developed after reflecting on three professional development (PD) courses, each with facilitators who are academic developers across the African continent. Using a Collaborative Autoethnographic methodology, the three authors reflect on design considerations for different forms of blended and online PD courses, based on their experiences of designing and/or facilitating these interventions and with PD more broadly. We argue that course designs can be positioned along a range of dimensions, namely open/closed, structured/unstructured, facilitated/unfacilitated, certified/uncertified, with/without date commitments, homogenous versus autonomous learning path, content vs. process centric, serious vs. playful, and individual vs. collaborative. We discuss relationships between dimensions and learning theories (the more open dimensions speak to connectivist, while more structured courses follow social constructivist approaches). We also identify various tensions that arise in the design of NPD, such as between academic developers’ pedagogical advocacy vs. usefulness, need to maintain volunteerism without exploitation of affective labour, and struggle to create spaces for agency within institutional constraints.
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Nothing forever
- Authors: Krueger, Anton
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225533 , vital:49233 , xlink:href="https://doi.org/10.5920/pam.1013"
- Description: Thank you to everybody who made contributions to this bumper 2021 Special Issue on Improvisation. Many thanks to our peer reviewers and especially to co-editors Deborah and Daniel for their help with the selection and editing process which has now culminated in a baker’s dozen texts. With contributions from Australia, South Africa, and New Zealand, as well as from France, the USA and the UK, the issue includes five interviews, four articles, two book reviews, a reflection and a score.
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Novel dynamic residue network analysis approaches to study allosteric modulation: SARS-CoV-2 Mpro and its evolutionary mutations as a case study
- Authors: Sheik Amamuddy, Olivier , Boateng, Rita A , Barozi, Victor , Nyamai, Dorothy W , Tastan Bishop, Özlem
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/476596 , vital:77940 , xlink:href="https://doi.org/10.1016/j.csbj.2021.11.016"
- Description: The rational search for allosteric modulators and the allosteric mechanisms of these modulators in the presence of mutations is a relatively unexplored field. Here, we established novel in silico approaches and applied them to SARS-CoV-2 main protease (Mpro) as a case study. First, we identified six potential allosteric modulators. Then, we focused on understanding the allosteric effects of these modulators on each of its protomers. We introduced a new combinatorial approach and dynamic residue network (DRN) analysis algorithms to examine patterns of change and conservation of critical nodes, according to five independent criteria of network centrality. We observed highly conserved network hubs for each averaged DRN metric on the basis of their existence in both protomers in the absence and presence of all ligands (persistent hubs). We also detected ligand specific signal changes. Using eigencentrality (EC) persistent hubs and ligand introduced hubs we identified a residue communication path connecting the allosteric binding site to the catalytic site. Finally, we examined the effects of the mutations on the behavior of the protein in the presence of selected potential allosteric modulators and investigated the ligand stability. One crucial outcome was to show that EC centrality hubs form an allosteric communication path between the allosteric ligand binding site to the active site going through the interface residues of domains I and II; and this path was either weakened or lost in the presence of some of the mutations. Overall, the results revealed crucial aspects that need to be considered in rational computational drug discovery.
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Overcoming hurdles facing researchers in Africa
- Authors: Nyokong, Tebello , Ngoy, Bokolombe P , Amuhaya, Edith K
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177511 , vital:42828 , https://doi.org/10.1038/s41563-021-00961-0
- Description: Several countries on the African continent recognize that a transition to a knowledge-based economic model would stimulate growth and enable scientific independence. Investing in new knowledge would drive the formation of highly qualified professionals and the use of advanced technologies, triggering in return positive economic trends. Importantly, a knowledge-based economy that values the impact of science on society would help reversing the migration of skilled workers and lead to brain gain.
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Parametrised gains for direction-dependent calibration
- Authors: Russeeaeon, Cyndie
- Date: 2021
- Subjects: Radio astronomy , Radio inferometers , Radio inferometers -- Calibration
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/172400 , vital:42196
- Description: Calibration in radio interferometry describes the process of estimating and correcting for instrumental errors from data. Direction-Dependent (DD) calibration entails correcting for corruptions which vary across the sky. For small field of view observations, DD corruptions can be ignored but for wide fild observations, it is crucial to account for them. Traditional maximum likelihood calibration is not necessarily efficient in low signal-to-noise ratio (SNR) scenarios and this can lead to ovefitting. This can bias continuum subtraction and hence, restrict the spectral line studies. Since DD effects are expected to vary smoothly across the sky, the gains can be parametrised as a smooth function of the sky coordinates. Hence, we implement a solver where the atmosphere is modelled using a time-variant 2-dimensional phase screen with an arbitrary known frequency dependence. We assume arbitrary linear basis functions for the gains over the phase screen. The implemented solver is ptimised using the diagonal approximation of the Hessian as shown in previous studies. We present a few simulations to illustrate the performance of the solver.
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Partial Purification and Characterization of Endoxylanase from a fungus, Leohumicola incrustata
- Authors: Adeoyo, Olusegun R , Pletschke, Brett I , Dames, Joanna F
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440393 , vital:73779 , 10.4314/br.v19i1.2
- Description: Xylanases are glycoside hydrolases (GH) that degrade β-1, 4-xylan, a linear polysaccharide found as hemicellulose in cell wall of plants. Endoxylanase (Endo-1, 4-β-xylanase, EC 3.2. 1.8) randomly catalyses xylan to produce varying short xylooligosaccharides (XOS). This study aimed to determine the characteristics of a partially purified endoxylanase from Leohumicola incrustata. Enzyme production was carried out using beechwood (BW) xylan, after which the cell-free crude filtrate was concentrated using the ammonium sulphate precipitation method. The hydrolysed products were analysed by thin-layer chromatography (TLC) and zymography. The result showed that the enzyme produced varying smaller-sized linear xylooligosaccharides with R f values corresponding to those of xylobiose, xylotriose, xylotetraose, xylopentaose, xylohexaose and other higher oligomers. The endoxylanase had a molecular mass of 72 kDa. The enzyme is stable in the presence of K+, Na+, Ca 2+, Fe 2+, Mg 2+, Zn 2+, Co 2+, pH of 5.0 and temperature of 37 o C. However, the activity gradually decreased after 60 min at 50 o C and retained over 69% activity after 120 min, while at 60 and 70 o C, the enzyme activity sharply decreased (pre-incubation periods). Endoxylanase from L. incrustata is comparable to those of other microorganisms and should be considered an attractive candidate for future industrial applications.
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Participatory data collection
- Authors: de Vos, Alta , Preiser, Rika , Masterson, Vanessa A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433842 , vital:73004 , ISBN 9781000401516 , https://library.oapen.org/handle/20.500.12657/49560
- Description: Participatory mapping (direct-to-digital participatory mapping, 3D-participatory mapping, participatory GIS), photovoice, transect walks, ranking exercises, focus group discussions, Venn diagrams, matrix scoring, ecograms, timelines, Q-methodology, community mapping, participatory videography, photo elicitation, seasonal calendars, participatory action research, participatory rural appraisal, participant observation, arts-based methods.
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