The motor insurance industry in South Africa: a survival analysis

Thesis (M.M. (Finance & Investment))--University of the Witwatersrand, Faculty of Commerce, Law and Management, Graduate School of Business Administration, 2015.An interesting phenomenon experienced in the insurance sector is the concept of underwriting cycles. The underwriting cycle challenge usually affects new registered insurers. When the premiums charged in the market are high, above the average, new players are prompted to enter the market and an underwriting cycle commences. New players in the insurance market may threaten the survival of the established companies. Established companies respond by strategically reducing their premiums below the average prices attracting clients by offering a better premium. This chokes the new insurers to death, and once they are out of business and there is less competition, the established insurers, will gradually increase their premiums to maintain profitability. What are the chances of survival of any new player in the short term insurance industry? Are there any significant differences in survival chances of motor insurers to non-motor insurers in the short term insurance sector? Are there any trends in the underwriting profits/losses for insurers who experienced death, years prior to death? Survival analysis methods enable us to answer these questions. We embarked on a survival analysis study, of short term insurance companies in South Africa, over a period of fourteen years. The Kaplan-Meir, test is used extensively in this project. We find that any new registered player in the motor and non-motor insurance industry has over 75% chance of survival over a period of 10 years. There are no significant differences in the survival functions of a motor and a non-motor insurer. Dormancy and fluctuations in net underwriting profits/losses are cited in the trend analysis of insurance companies that experience deat

The function and significance of war names in the Zimbabwean armed conflict (1966-1979)

This study is a survey of war names adopted by guerrillas during the Zimbabwean conflict (1966-1979). The study collects, describes and analyses war names that were used by ZANLA guerrillas in the conflict. It explores onomastic patterns and processes that influenced these war names. Names collected from textual sources and from interviews of former guerrillas are analysed and classified into nine categories. One of the main findings is that the background of the namer influenced the naming patterns and processes identified in the study. Another finding is that most guerrillas named themselves and it was also observed that some guerrillas have retained their names. The findings, analysed within the theoretical framework developed earlier from the onomastic and identity theories, indicate that the war name plays a vital role not only in concealing the old identity of the guerrilla but also in creating new identities, which were used as weapons for challenging the enemy and contesting space. Onomastic erasure and resuscitation are proposed as partial explanation for the creation of some war names. The study contributes to onomastic research not only in that it has produced a large corpus of war names that can be used for further research in that it is a significant point of reference in onomastic research in Zimbabwe and in southern Africa, especially in the area of nicknames and war names. It also lays the foundation for further research on the role of naming patterns and processes in peace building and conflict resolution in Zimbabwe, on the southern African subcontinent and elsewhere.Thesis (D. Litt et Phil.

Sorghum value chain analysis in semi-arid Zimbabwe

The role of extension in strengthening relationships among stakeholders along agricultural commodity value chains remains an important discussion point especially with orphan crops in semi-arid areas. The study used a participatory framework to analyse the sorghum value chain in the Mid Zambezi Valley of Zimbabwe. A sample comprising of 380 small scale farmers, proportionately selected from five major sorghum producing wards, was used. Six agrodealers, 15 traders, 10 retailers, three wholesalers, and two processors were also sampled. Inaddition, focus group discussions, informant interviews, questionnaires and reviews of records were conducted. Input supply systems for sorghum are weakly developed and production is stalled by inappropriate innovations including seed and fertilizer application. Marketing and processing channels are limited due to erratic supply and low producer prices. Demand for sorghum inputs can be created by engaging extension agents in helping farmers with realising the benefits of using improved sorghum seed varieties and fertilizer in sorghum production. This will smoothen the flow of sorghum products along strategic value chain nodes.Keywords: Sorghum, small scale farmers, value chain, extension networks, marketing margins, agribusines

Synthesis, Structure and Crystallization Behavior of Amphiphilic Hetero-arm Molecular Brushes with Crystallizable Poly(ethylene oxide) and N-Alkyl Side Chains

Unformatted post-print version of the accepted articleA series of hetero-arm amphiphilic molecular brushes (AMBs) with poly(ethylene glycol) (PEG) and long chain n-alkyl side chains were synthesized via conventional free radical polymerization (FRP) of mainly 4-vinyl benzyl-PEG methyl ether and N-alkylmaleimide macromonomers. By varying PEG side chain degree of polymerization (D.P. = 12, 16 and 20) and n-alkyl chain lengths (C16 and C20), AMBs with varying combinations of side chain lengths were produced. This enabled the elucidation of the effect of side chain length on AMB phase behavior, semicrystalline morphologies and crystallization kinetics, via differential scanning calorimetry, polarized light optical microscopy and x-ray diffraction experiments. Calculations of segregation strength together with SAXS measurements indicate that all materials are probably phase segregated structure in the melt. Most of the AMB materials prepared were double crystalline, i.e., contained crystals from alkyl and PEG chains. AMB crystallization was constrained by AMB architecture, the frustration being most evident in AMBs with combinations of either low D.P.PEG, or short alkyl chain lengths. Large, well-developed spherulites, implying break-out crystallization from a weakly segregated melt, were only observed for the AMBs with the combination of the longest PEG chain (D.P. = 20) and longest alkyl chain length (C20). A peculiar behavior was found when spherulitic growth rates and overall crystallization rates of the PEG chains, within this particular AMB sample, were determined as a function of crystallization temperature. In both cases, a distinct minimum with decreasing temperature was observed, probably caused by the challenges encountered in crystal packing of the PEG side chains, tethered to an amorphous backbone, which also contained already crystallized C20 chains. This minimum is analogous to that observed in the crystallization of long chain n-alkanes, or high molar mass polyethylenes with bromine pendant groups that has been attributed to a self-poisoning effect; this is the first observation of this phenomenon in AMBs.This work is based on the research supported by the South African Research Chairs Initiative of the Department of Science and Technology (DST) and National Research Foundation (NRF) of South Africa (Grant No 46855). J.M. acknowledges support from the Provincial Council of Gipuzkoa under the program Fellow Gipuzkoa and “Fomento San Sebastián” in the framework program “Retorno del Talento Local” Donostia up! 2016. This work has received funding from the European Union´s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 778092, from MINECO, project: MAT2017-83014-C2-1-P and from the Basque Government through grant IT1309-19. We also thank ALBA Synchrotron facility for providing funding and beam time (proposal number: 2018082953)

Facile route to targeted, biodegradable polymeric prodrugs for the delivery of combination therapy for malaria

A facile synthetic methodology has been developed to prepare multifaceted polymeric prodrugs that are targeted, biodegradable, and nontoxic, and used for the delivery of combination therapy. This is the first instance of the delivery of the WHO recommended antimalarial combination of lumefantrine (LUM, drug 1) and artemether (AM, drug 2) via a polymeric prodrug. To achieve this, reversible addition-fragmentation chain transfer (RAFT)-mediated polymerization of N-vinylpyrrolidone (NVP) was conducted using a hydroxy-functional RAFT agent, and the resulting polymer was used as the macroinitiator in the ring-opening polymerization (ROP) of α-allylvalerolactone (AVL) to synthesize the biodegradable block copolymer of poly(N-vinylpyrrolidone) and poly(α-allylvalerolactone) (PVP-b-PAVL). The ω-end thiol group of PVP was protected using 2,2′-pyridyldisulfide prior to the ROP, and was conveniently used to bioconjugate a peptidic targeting ligand. To attach LUM, the allyl groups of PVP-b-PAVL underwent oxidation to introduce carboxylic acid groups, which were then esterified with ethylene glycol vinyl ether. Finally, LUM was conjugated to the block copolymer via an acid-labile acetal linkage in a “click”-type reaction, and AM was entrapped within the hydrophobic core of the self-assembled aggregates to render biodegradable multidrug-loaded micelles with targeting ability for combination therapy.The South African Research Chairs Initiative of the Department of Science and Technology (DST), the National Research Foundation (NRF) of South Africa, SARCHI: Communities of Practice in Malaria Elimination and SARChI Research Chair UID 84627 and UID 84627.http://pubs.acs.org/journal/abseba2021-10-07hj2021BiochemistryGeneticsMicrobiology and Plant Patholog

Influence of DIBMA polymer length on lipid nanodisc formation and membrane protein extraction

Polymer-based lipid nanoparticles like styrene-maleic acid lipid particles have revolutionized the study of membrane proteins. More recently, alternative polymers such as poly(diisobutylene-alt-maleic acid) (DIBMA) have been used in this field. DIBMA is commonly synthesized via conventional radical copolymerization. In order to study the influence of its chain length on lipid nanodisc formation and membrane protein extraction, we synthesized DIBMA with molar masses varying from 1.2–12 kDa via RAFT-mediated polymerization. For molar masses in the range of 3–7 kDa, the rate of lipid nanodisc formation was the highest and similar to those of poly(styrene-co-maleic acid) (SMA) and commercially available DIBMA. ZipA solubilization efficiency was significantly higher than for commercially available DIBMA and similar to SMA (circa 75%). Furthermore, RAFT-made DIBMA with a molar mass of 1.2–3.9 kDa showed a much cleaner separation on SDS–PAGE, without the smearing that is typically seen for SMA and commercially available DIBMA

Linear dichroism activity of chiral poly(p-Aryltriazole) foldamers

Controllable higher-order assembly is a central aim of macromolecular chemistry. An essential challenge to developing these molecules is improving our understanding of the structures they adopt under different conditions. Here, we demonstrate how flow linear dichroism (LD) spectroscopy is used to provide insights into the solution structure of a chiral, self-assembled fibrillar foldamer. Poly(para-aryltriazole)s fold into different structures depending on the monomer geometry and variables such as solvent and ionic strength. LD spectroscopy provides a simple route to determine chromophore alignment in solution and is generally used on natural molecules or molecular assemblies such as DNA and M13 bacteriophage. In this contribution, we show that LD spectroscopy is a powerful tool in the observation of self-assembly processes of synthetic foldamers when complemented by circular dichroism, absorbance spectroscopy, and microscopy. To that end, poly(para-aryltriazole)s were aligned in a flow field under different solvent conditions. The extended aromatic structures in the foldamer give rise to a strong LD signal that changes in sign and in intensity with varying solvent conditions. A key advantage of LD is that it only detects the large assemblies, thus removing background due to monomers and small oligomers

Poly(N-vinylpyrrolidone) antimalaria conjugates of membrane-disruptive peptides

The concepts of polymer–peptide conjugation and self-assembly were applied to antimicrobial peptides (AMPs) in the development of a targeted antimalaria drug delivery construct. This study describes the synthesis of α-acetal, ω-xanthate heterotelechelic poly(N-vinylpyrrolidone) (PVP) via reversible addition–fragmentation chain transfer (RAFT)-mediated polymerization, followed by postpolymerization deprotection to yield α-aldehyde, ω-thiol heterotelechelic PVP. A specific targeting peptide, GSRSKGT, for Plasmodium falciparum-infected erythrocytes was used to sparsely decorate the α-chain ends via reductive amination while cyclic decapeptides from the tyrocidine group were conjugated to the ω-chain end via thiol–ene Michael addition. The resultant constructs were self-assembled into micellar nanoaggregates whose sizes and morphologies were determined by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The in vitro activity and selectivity of the conjugates were evaluated against intraerythrocytic P. falciparum parasites.© 2020 American Chemical Societyhttp://pubs.acs.org/journal/bomaf62021-11-06hj2021BiochemistryGeneticsMicrobiology and Plant Patholog

Phytochemical analysis, antioxidant and antimicrobial effects of extracts from grape (Vitis vinifera) by-products and mandarin orange (Citrus reticulata Blanco)

Thesis (MScFoodSc)--Stellenbosch University, 2018.ENGLISH ABSTRACT: The increase in level of customer sophistication, motivated by a general interest in healthier food options, has seen growing focus on fruit by-products processing and value addition as a potential source of natural preservatives. In this study, the phytochemical composition, pH, titratable acidity, antioxidant and antimicrobial properties of extracts from orange peel and pulp (OPE), grape pomace (GPE) and seeds (GSE) grown in South Africa were analysed. Spectrophotometric methods were used to quantify total phenols, total tannins, flavonoids, anthocyanins, proanthocyanidins, as well as ascorbic acid and total carotenoids. The pH was measured using a laboratory pH meter while a titrosampler was used to measure the titratable acidity. Antioxidant properties were evaluated using the 2,2-diphenyl-1-picrylhydrazyl radical-scavenging method, ferric reducing-antioxidant power test, oxygen radical absorbance capacity assay and the lipoxygenase inhibition assay. Comparisons were made against ascorbic acid used commercially as an antioxidant preservative. The antimicrobial properties were evaluated against five bacteria (Listeria monocytogenes, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa) and one yeast (Candida albicans) using the broth microdilution method with comparisons against tetracycline (positive indicator) and sodium metabisulphite (artificial antimicrobial preservative). Total phenols and carotenoids were highest in GPE followed by GSE and OPE (p ≤ 0.05). Flavonoids and anthocyanins were higher (p ≤ 0.05) in GPE and GSE compared to OPE. The GSE had highest proanthocyanidins followed by GPE and OPE (p ≤ 0.05). Ascorbic acid was only detected in OPE, which also had the highest titratable acidity and lowest pH (p ≤ 0.05). The GSE had the highest antioxidant activity based on all four antioxidant assays, as evident in GSE having the highest antioxidant potency composite index followed by GPE and OPE (p ≤ 0.05). The extracts showed less antimicrobial activity compared to the positive indicator and artificial antimicrobial preservative. Greatest antimicrobial activity among the extracts, however, was shown by OPE. The order of antimicrobial activity of the extracts was OPE > GSE > GPE (p ≤ 0.05). Current findings show that GSE is a potential antioxidant while OPE holds promise as an antimicrobial for the food industry. Overall, valorisation of fruit processing by-products is a promising avenue for enhancing food preservation and shelf life stability while offsetting environmental problems due to waste dumping.AFRIKAANSE OPSOMMING: Die toename in die vlak van verbruikers se gesofistikeerdheid, gemotiveer deur 'n algemene belangstelling in gesonder kos-opsies, het toenemende fokus begin plaas op die verwerking van en dus waardetoevoeging tot vrugtebyprodukte wat as 'n potensiële bron van natuurlike preserveermiddels gebruik kan word. In hierdie studie is die fitochemiese samestelling, pH, titreerbare suurheid, antioksidante en antimikrobiese eienskappe van ekstraksies van lemoenskil en -pulp (OPE), druiwepulp (GPE) en -pitte (GSE) verbou in Suid-Afrika, ontleed. Spektrofotometriese metodes is gebruik om totale fenole, totale tanniene, flavonoïede, antosianiene, pro-antosianidiene, sowel as askorbiensuur en totale karotenoïede te kwantifiseer. Die pH is gemeet met behulp van 'n laboratorium pH meter, terwyl 'n titrosampler gebruik is om die titreerbare suurstof te meet. Antioksidant eienskappe is geëvalueer deur gebruik te maak van die 2,2-difenyl-1-pikrylhidrasiel radikaal-opruimingsmetode, die reduksie-antioksidant kragtoets, die suurstof-radikaal absorbansiekapasiteitsassessering en die lipoksigenase-inhibisie-toets. Vergelykings is gemaak teen askorbiensuur wat kommersieel gebruik word as 'n antioksidant preserveermiddel. Die antimikrobiese eienskappe is geëvalueer teen vyf bakterieë (Listeria monocytogenes, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa) en een gis (Candida albicans) met behulp van die sous-mikroverdunningsmetode met vergelykings teen tetrasiklien (positiewe aanwyser) en natrium metabisulfiet (kunsmatige antimikrobiese preserveermiddel). Totale fenole en karotenoïede was die hoogste in GPE, met laer vlakke in GSE en OPE. Flavonoïede en antosianiene was hoër in GPE en GSE, wanneer vergelyk met OPE. Die GSE het die hoogste pro-antosianidien inhoud, met laer vlakke gevind in GPE en OPE. Askorbiensuur is slegs in OPE gevind, wat ook in die bron die hoogste titreerbare suurheid en laagste pH gehad het. Die GSE het die hoogste antioksidant aktiwiteit op grond van al vier antioksidant-toetse gehad, soos blyk uit GSE wat die hoogste saamgestelde indeks van antioksidant potensiaal het, gevolg deur GPE en OPE. Die onderskeie ekstraksies het minder antimikrobiese aktiwiteit getoon in vergelyking met die positiewe indikator en kunsmatige antimikrobiese preserveermiddel. Die grootste antimikrobiese aktiwiteit onder die ekstraksies is egter deur OPE getoon. Die volgorde van antimikrobiese aktiwiteit van die uittreksels was OPE> GSE> GPE. Huidige bevindinge toon dat GSE 'n potensiële antioksidant is, terwyl OPE belofte as 'n antimikrobiese verbinding vir die voedselbedryf inhou. In geheel, die waardetoevoeging tot die byprodukte van verwerkte vrugte het potensiaal om by te dra tot die verbetering van voedselbehoud en rakleeftydstabiliteit, terwyl die omgewingsprobleme weens afvalstorting ook hiermee aangespreek kan word.Master