Symmetry Properties of Autonomous Integrating Factors

We study the symmetry properties of autonomous integrating factors from an algebraic point of view. The symmetries are delineated for the resulting integrals treated as equations and symmetries of the integrals treated as functions or configurational invariants. The succession of terms (pattern) is noted. The general pattern for the solution symmetries for equations in the simplest form of maximal order is given and the properties of the associated integrals resulting from this analysis are given.Comment: Published in SIGMA (Symmetry, Integrability and Geometry: Methods and Applications) at http://www.emis.de/journals/SIGMA

Exploring limits to performativity : (re)constituting everyday performances through planned change

This thesis addresses a critical conundrum in the strategy-as-practice debate: to what extent and under what conditions can a model be performative during the co-performation of routines and strategy? The concept of performativity argues that models do not merely describe settings but transform and shape the reality within these settings. As evidenced by the failure of most change initiatives, not all models successfully transform settings. Drawing on an ethnographic study of interactional patterns of action in the context of a complex technology-mediated, boundary spanning professional service routine; this work explores the limits to progression and diffusion of a planned change model’s performativity during the co-performation of routines and strategy to achieve the purposeful routinisation and coordination of organizational activities. Through identifying the felicity and infelicity conditions for the performativity of a planned change model and analyzing their dynamic interplay, I develop a model for the co-performation of routines and strategy; and propose a framework for the model’s empirical limits to performativity. I argue that these limits demarcate the space for ‘performativity struggles’ and provide a framework for the analysis of ‘performativity failures’ for new strategy. I add to the literature on strategy-as-practice through theorising on the empirical limits to performativity – a key dynamic within strategy praxis that is as yet under studied within the strategy-as-practice approach.This thesis addresses a critical conundrum in the strategy-as-practice debate: to what extent and under what conditions can a model be performative during the co-performation of routines and strategy? The concept of performativity argues that models do not merely describe settings but transform and shape the reality within these settings. As evidenced by the failure of most change initiatives, not all models successfully transform settings. Drawing on an ethnographic study of interactional patterns of action in the context of a complex technology-mediated, boundary spanning professional service routine; this work explores the limits to progression and diffusion of a planned change model’s performativity during the co-performation of routines and strategy to achieve the purposeful routinisation and coordination of organizational activities. Through identifying the felicity and infelicity conditions for the performativity of a planned change model and analyzing their dynamic interplay, I develop a model for the co-performation of routines and strategy; and propose a framework for the model’s empirical limits to performativity. I argue that these limits demarcate the space for ‘performativity struggles’ and provide a framework for the analysis of ‘performativity failures’ for new strategy. I add to the literature on strategy-as-practice through theorising on the empirical limits to performativity – a key dynamic within strategy praxis that is as yet under studied within the strategy-as-practice approach

Leveraging on past investment in understanding the immunology of COVID-19 – the South African experience.

Significance:The COVID-19 pandemic, and in particular the emergence of viral variants, resulted in an enormous global public health crisis. South African scientists, with a long history of studying viral evolution and antibody responses, were well positioned to pivot their research to focus on SARS-CoV-2. Using the expertise and infrastructure developed over decades for HIV vaccine research, South Africa took a leadership role in studying the antibody response elicited by SARS-CoV-2 infection and vaccination. We describe key scientific outcomes of those studies, and the drivers of a successful national response

Perceptions of climate change and adaptation to microclimate change and variability among smallholder farmers in Mhakwe Communal Area, Manicaland province, Zimbabwe

Climate change and the related increasing variability are real phenomena in sub-Saharan Africa. They are exacerbating climatic risks associated with small-scale agriculture in tropical regions. This study seeks to assess smallholder farmers' perceptions of climate change and also their adaptive strategies at the microscale in Mhakwe Communal Area in Zimbabwe. A mixed method research design was employed to carry out the study. The design was a triangulation of quantitative and qualitative data collection methods. A sample of 43 smallholder farmers was purposively selected because the population of smallholder farmers was unknown. The study noted that government agencies and non-governmental organisations were providing information about climate change and variability to smallholder farmers. Farmers practiced a number of adaptation strategies such as timing in planting, zero tillage, mulching, agroforestry and gardening. The study recommended that external agencies should focus on strengthening existing adaptive strategies. There is also need to scale-up programmes on capacity building with regards to dissemination of analysed weather andclimate data.Key Words: Climate change; Adaptation; Agriculture; Smallholder farmers, Vulnerabilit

Analysis of Essential Elements for Plants Growth Using Instrumental Neutron Activation Analysis

In this study, a total of ten essential elements for plants growth in the Guinea savanna region of Niger State in Northern Nigeria have been identified in the soils using instrumental neutron activation analysis. The experimental results show good agreement with certified or literature values within the agreed percentage range of ±2.35% to ±8.69%. However, the concentration distributions of the ten identified elements in the soil samples within the studied area for plants growth revealed the following: Fe (123.4 ppm), Mn (2100.7 ppm), K (5544.3 ppm), Al (54752.4 ppm), Ti (3082.9 ppm), Ca (4635 ppm), V (54.3 ppm), Na (857.5 ppm), Mg (13924.1 ppm), and Dy (12.1 ppm). A further analysis of the two fundamental soil physical parameters for healthy growth of some common crops like egusimelon, groundnut, rice, yams, soybeans, cassava, and potato analyzed in this work revealed a pH range of 4.0 pH–8.0 pH and a temperature range of 28.0°C to 29.3°C, which are optimal for plant nutrients availability in the soils within the study area

Susceptibility of Grapevine Sucker and Green Shoot Wounds to Trunk Disease Pathogens

Grapevine trunk disease fungi infect vines through openings, primarily pruning wounds. The main objective of this study was to understand the role of sucker wounds and wounds made by the removal of green shoots from the stems of potted grapevines as potential points of infection for grapevine trunk disease pathogens. Six wine and four table grape vineyards of different ages were sampled in differentproduction areas in the Western Cape grape region of South Africa. Isolations were made from 161 sucker wounds, and fungal pathogens were identified using morphology and DNA sequence analysis of the internal transcribed spacers (ITS1 and ITS2) and the 5.8S ribosomal RNA gene, the translation elongation factor 1alpha or the partial β-tubulin gene. The results show that 62% of the sucker wounds were infected by trunk disease pathogens, including Diaporthe ampelina, Diplodia seriata, Phaeomoniella chlamydospora, Phaeoacremonium minimum, Eutypella microtheca, Cryptovalsa ampelina and Neofusicoccum australe.  Diaporthe ampelina was the most common, followed by D. seriata and P. chlamydospora, in both the wine and table grape sucker wounds. Under glasshouse conditions, wounds made by the removal of young green shoots on one-year-old potted grapevine plants were inoculated with spore suspensions of D. ampelina, E. lata, N. parvum, P. minimum and P. chlamydospora. After four months, all the inoculated pathogens could be re-isolated. This study shows that grapevine sucker and green shoot wounds are susceptible to different grapevine trunk disease pathogens and may therefore play a role in the epidemiology of trunk diseases

Aflatoxins contamination in processed cassava in Malawi and Zambia

Strains of the Aspergillus fungi, especially A. flavus and A. parasiticus, primarily produce aflatoxins which are a major health concern to man and livestock because of their acute and chronic health effects. Aflatoxins pose the greatest risk to health in tropical Africa because of their widespread prevalence and high toxicity; carcinogenic (cause liver and esophageal cancer) effect, immune system suppressing and anti-nutritional  contaminants in many food commodities and even cause death. Aflatoxins have also been reported to compromise vaccine efficacy in experimental animals. Due to the seriousness of aflatoxins, international agencies have restricted levels of aflatoxins to 20 ppb in food materials as the maximum permissible level in the United States and 4 ppb total aflatoxins and under 2 ppb aflatoxin B1 in Europe. These regulations directed at minimizing human exposure to aflatoxins results in severe economic loss to producers, processors and marketers of the contaminated crop. A study was conducted in Malawi and Zambia to assess the level of fungal and mycotoxins’ contamination in commonly processed cassava products. A total of 92 and 88 samples of processed cassava products comprising makaka, flour, kanyakaska, kadonoska, scrapes and grates were collected in the rainy season of 2008 and 2009 in Malawi, respectively. Further, 22 samples of processed cassava products comprising dried cassava chips and flour were collected in the rainy season of 2009 in Zambia. The samples were analyzed for fungal and aflatoxins B1, B2, G1 and G2 contamination using the Romer mini-column method and the VICAM AflaTest  immunoaffinity fluorometric method. None of the samples in 2008 were contaminated with aflatoxins. Similar results were obtained in 2009 with almost all the samples in Malawi and Zambia having aflatoxin levels much lower (<2.0 ìg/kg in Malawi and <4.2 ìg/kg in Zambia) than the Codex Alimentarius Commission (CAC) maximum permissible level of aflatoxins of 10.0 ìg/kg, implying that the cassava products analyzed were safe for human consumption. However, further studies are needed to cover a larger sample size over a period of a year to represent all seasons in the cassava producing and consuming areas and conclusively make certain the safety of these products for human consumption.Key words: Cassava, consumption, aflatoxin, food, safet

The spatial and temporal characterisation of flooding within the floodplain wetland of the Nyl River, Limpopo Province, South Africa

The inundated area of a wetland is characterised by annual and interannual variability. This paper presents remotely-sensed imagery in order to better understand the spatial and temporal patterns of flooding within the floodplain wetland of the Nyl River, Limpopo Province. A detailed understanding of the hydrological characteristics of these flood events is essential in order to develop sustainable ecological and hydrological management plans for the area. From the results, flooding is shown to occur in 2 distinct phases. The initial phase is characterised by water ponding on the floodplain. The later phase is characterised by the input of water from tributaries to the north (e.g. Andriesspruit and Tobiasspriut) and southwest (e.g. Klein Nyl and Groot Nyl). This distinction may relate to the increasingly widespread practice of agricultural irrigation within adjacent tributary catchments. The methodology described in this study could yield valuable results when applied to other wetland systems in southern Africa.Keywords: Landsat, remote sensing, flood dynamics, floodplain wetlands, Nyl Rive

Re-tracing invisible maps : landscape in and as performance in contemporary South Africa

This thesis suggests an approach to landscapes both in and as performance, in order to explore how identity and belonging are sited and performed in contemporary South Africa. I deploy an inter-disciplinary concept of landscape, drawing from the work of Tim Ingold (2000), who defines landscape as 'a plenum' and argues that we engage with landscapes through a performative process of 'way-finding.' With this in mind, I position myself as a participant-observer in this thesis, and through a process of way-finding aim to 're-trace invisible maps' of identity in a selection of examples ranging from the theatrical to the everyday. Throughout my discussion I analyse how specific performances reflect/resist certain histories and social constructions of belonging. The thesis is divided into three thematic sections which explore how various cultural practices, or forms of 'mapping', attempt to make the world 'knowable', at the same time indicating what escapes or exceeds the limits of their own codes of representation. The first section entitled Fortress City investigates identity formation as a spatially situated process in Cape Town, using the example of the public arts festival Infecting the City and focusing on the period 2009-2011 when it was curated by Brett Bailey. In the second section Frontier Nations, I discuss the temporality of landscape by juxtaposing how collective/national memory and subjective/personal memory both emerge in and through performance. I compare two speeches made by Presidents Mandela and Zuma in Grahamstown in 1996 and 2011 respectively, and contrast the political rhetoric on nationhood with Brett Bailey’s use of mythic time in an experiential site-specific performance Terminal (2009). In the last section Corporeal Networks, I argue that the body acts as primary generator of meaning, identification and belonging. I discuss Juanita Finestone-Praeg’s Inner Piece (2009) a physical theatre work which tackles issues of violence and representation