Bounds on baskets option prices

Includes bibliographical references (leaves 70-71).The celebrated Black-Scholes option pricing model is unable to produce closed-form solutions for arithmetic basket options. This problem stems from the lack of an analitical form for the distribution of a sum of lognormal random variables. lVlarket participants commonly price basket options by assuming the basket follows lognormal dynamics, although it is known that this approximation performs poorly in some cicumstances. The problem of finding an analytical approximation to the sum of lognormally distributed random variables has been widely studied. In this dissertation we seek to draw these studies together and apply them in an option pricing setting. We propose some new option pricing formulae based on these approximations. In order to examine the utility of these new formulae and compare them to commonly used market approximations we present rigorous analytical bounds for the price of arithmetic basket options using the theory of comonotonicity. In this we follow the ideas in Deelstra et al. [7]. Additionally we provide an interval of hedge parameters (the Greeks). We carry out a numerical sensitivity analysis and identify circumstances under which the market approximation misprices basket options

Meta-modes of learning that support and influence the millennial student’s holistic learning experience at an academic institute in South Africa

Teaching in diverse ways to a diverse generation, globally, academic institutes must ensure that learning is responsive, appropriate and supportive of cohorts in emerging and involving modes of learning. However, the pedagogy, processes and learning methods are of paramount importance for this diverse student generation in order to recognise subsequent cohorts for whom motivation and engagement in a holistic learning experience for millennial students could be maximised. While it has been recognised that current learning practices may not address the holistic learning experience of the millennial student, the purpose of this study, through the adoption of the Student-Owned Learning-Engagement (SOLE) model, its nine elements and 42 meta-modes of learning, is to investigate and identify the confluence of meta-modes of learning that could support and influence the millennial student’s holistic learning experience. In response to the needs of aspiring millennial learners, data were obtained from 69 students and 15 teachers by means of a self-administrated questionnaire. A comparison was drawn between the theories that the millennials preferred meta-modes of learning and the modes of teaching that the teachers had adopted. Hence, this study offers strategies to improve the holistic experience of learning. This is performed in a manner that support new empirical emerging and involving modes of learning for the millennial student

Investigating the effects of mopane worms (Imbrasia belina) on nutrients, Venetia-Limpopo Nature Reserve, South Africa

Ecologists have long been aware that large mammalian herbivores can alter ecosystem functioning in various ways, for example through changing where they defecate and urinate, which consequently affects nutrient cycling. The effects of herbivorous insects on ecosystems, however, have received limited attention until recently. Insects are capable of mass outbreaks, they can consume large volumes of vegetative material and can deposit large quantities of dung (frass), one example being the mopane worm, Imbrasia belina. This study looked at the effect of mopane worm frass on soil fertility in the mopane veld of the Venetia-Limpopo Nature Reserve and neighbouring Haakdoring farm. It found that mopane worms are capable of altering soil nutrient dynamics beneath the trees where they are browsing in three ways. Firstly, they increase the potential amount of nutrients deposited when compared with that deposited through conventional leaf litter. Secondly, they alter the rate of nutrient recycling by depositing nutrients in frass which decomposes more rapidly than conventional leaf litter. Lastly, they increase the amounts of potassium and phosphorus in the soil. While there is no conclusive data from this study that the mopane veld would become extinct if mopane worms were harvested to extinction, it has shown that there is relatively little evidence on how herbivorous insects could affect ecosystem functioning in the landscapes in which they occur. Further research is recommended that investigates how mopane worms influence soil fertility in more detail and over multiple geographical locations

An industry-sponsored, school-focused model for continuing professional development of technology teachers

Traditionally a divide has existed between faculties of education at higher education institutions (HEIs) and trade and industry, but the business sector is increasingly buying into community development with corporate social investment, especially regarding technology education. We report on a continuing professional teacher development (CPTD) model, which entails trade and industry sponsoring learning and teacher support material (LTSM) for technology education in under-resourced schools, paying for LTSM through their corporate social investment funds, and sponsoring CPTD of technology teachers where they are trained to use LTSM more efficiently. Trade and industry, together with HEIs and Departments of Education (DoE), could change the traditional concept that CPTD is the responsibility of DoEs into a new model where the business sector shares some of the responsibility for equipping teachers so that they can provide quality education. We argue that custom-made and sponsored LTSM and CPTD play an important role in the training and empowerment of technology teachers

Speaking with rape survivors : an analysis of the stories women share

Includes bibliographical references (leaves 109-117).Rape is an all too familiar phenomenon in South Africa. Yet, whereas there is a growingliterature in the west, which examines the everyday understandings of rape amongst women, inSouth Africa documented understanding of rape is largely contained within theoretical-sociological explanations for its high prevalence. This study aimed to explore the ways in which a group of rape survivors in the Western Cape, South Africa, make sense of rape and its impact on their lives. A secondary aim was to examine whether Western trauma classifications provide a useful framework for understanding the impact of rape in this context. The study formed the qualitative component of a larger quantitative study focused on women's adherence to anti-retroviral medication post rape (The Post Exposure Prophylaxis Study). The research question was approached from a feminist social constructionist perspective, using qualitative methodology. In depth interviews with ten rape survivors were carried out, six months postrape

An industry-sponsored, school-focused model for continuing professional development of technology teachers

Traditionally a divide has existed between faculties of education at higher education institutions (HEIs) and trade and industry, but the business sector is increasingly buying into community development with corporate social investment, especially regarding technology education. We report on a continuing professional teacher development (CPTD) model, which entails trade and industry sponsoring learning and teacher support material (LTSM) for technology education in under-resourced schools, paying for LTSM through their corporate social investment funds, and sponsoring CPTD of technology teachers where they are trained to use LTSM more efficiently. Trade and industry, together with HEIs and Departments of Education (DoE), could change the traditional concept that CPTD is the responsibility of DoEs into a new model where the business sector shares some of the responsibility for equipping teachers so that they can provide quality education. We argue that custom-made and sponsored LTSM and CPTD play an important role in the training and empowerment of technology teachers. Keywords: continuing professional development; learning and teacher support material; technology education South African Journal of Education Vol. 27 (4) 2007: pp. 579-59

Aroma: a larger than life experience?

Aroma is today an essential part of our diet. Often used to reinforce the initial neutral taste of the food produced on an industrial scale, it is sometimes the main course, at the core of many edible products. First thought as accessory, it now takes the lead. From this observation and through the review of examples of the food industry, this article puts forward the hypothesis that the aroma supplants the food –in the relation of resemblance between the original model and its representation, which falls under the inculcation – and eclipses it. Potentially strong on the palate, it is a promise of intense experience. This is particularly true in the case of flavors without pre-established references. Pure abstract aromatic constructions allow greater freedom of projection, and foster discursive emphasis. In these cases, the taste alone, uncorrelated with prerogatives of nutrition, becomes the support of a hyperesthesic experience

Blood dendritic cells in chronically HIV-1 infected individuals in South Africa: Phenotype, function and immune modulation

Thesis (PhD)--Stellenbosch University, 2016ENGLISH ABSTRACT :HIV-1 infection detrimentally affects CD4 T lymphocytes as well as the blood plasmacytoid (pDC) and myeloid dendritic cell (mDC) compartment. DCs act as innate sensors and as initiators and directors of antigen-specific immune responses. Whereas, mDCs have the unique ability to prime naïve T-lymphocytes and activate adaptive immune responses, pDCs are primary producers of type 1 interferons (IFNs), playing a pivotal role in anti-viral immunity. In the current study both pDCs and mDCs from chronically HIV-1 infected South African individuals (on or naïve for ARV therapy) as well as with and without concurrent TB disease, were compared to matched uninfected controls. Similar to CD4 T lymphocytes, bothpDCs and mDCs, were significantly depleted during HIV-1 infection, (reduction of pDC, mDC and CD4 T lymphocyte was 63% (p 0.001), 80% (p 0.001) and 31% (p 0.01), respectively). In parallel, significantly higher levels of generalised immune activation and exhaustion (CD38+CD8+, PD-1+CD8+ and CD38+PD-1+CD8+ T lymphocytes) were observed. ARV treatment ( 1 year) did not result in DC number recovery despite a significant increase of CD4 T lymphocytes numbers (CD4 T lymphocyte number gain of 89% (p 0.01), it fell short of full recovery).TB co-infection did not exacerbate number loss. Phenotypic characterisation of DC populations in circulation during HIV-1 infection may indicate the underlying reasons for the loss from circulation. Phenotypic profiling by multiparameter flow cytometry included: markers of activation (CD86, CD80 and CD62L), maturation (CD83), apoptosis (TNF-R2, FAS, FASL and TRAIL R1-R4) and chemotaxis (CCR5, CCR7, CCR9 and CXCR6). HIV-infection was associated with a significantly higher percentage of CD86+mDCs which may be indicative of early maturation or transition to secondary lymphoid tissue. The frequency of the CD86+mDCs subset normalised upon ARV therapy. Also, HIV-1 infection influenced the distribution of TNF-R2+pDCs and TNF-R2+mDCs. Increased TNF-R2 expression in both subsets, may attest to enhanced survival function. Functionally, DCs of HIV-1 infected individuals were reactive to TLR-L stimulation and in some cases showed enhanced responses compared to uninfected individuals. A significantly higher frequency of TNF-R2+pDCs, IFN- +pDCs, and TNF +mDCs was observed in whole blood TLR cultures of HIV-1 infected individuals (TNF-R2+pDCs: LPS (p = 0.002) and R848 (p = 0.01), IFN- +pDCs: R848 (p = 0.04), TNF +mDCs: LPS (p = 0.003))s.In addition, whole blood TLR cultures of the ARV treated study group generally showed normalisation of the responses, however; in certain cases ARV therapy reduced responsiveness to levels significantly lower than the control study group (i.e.TNF-R2+pDCs and TNF-R2+mDCs in CpG ODN stimulation). In contrast, a significantly lower frequency of IL12p40+mDCs was observed during HIV-1 infection (p = 0.02). TLR-L cultures of the ARV treated study groups showed normalisation of IL12p40+mDCsfrequency. Notably, treatment with the immunomodulating peptide VIP induced a decline in IL12p40+mDCs to levels lower than the control study group.The frequency of TNF +pDCs in TLR-L whole blood cultures was similar between the healthy, untreated and treated HIV-1 infected study groups, however, significantly reduced frequencies were observed in these study groups upon VIP treatment. These data indicate unique phenotypic and functional changes in DC subsets in chronic HIV- 1 infection which may provide potential targets for immunotherapeutic intervention.AFRIKAANSE OPSOMMING : Die CD4 T limfosiet asook die plasmasito ede (pDSe) en myelo ede dendritiese selle (mDSe) word nadelig geraak deur `n MIV-1 infeksie. Dendrietiese selle tree op as aangebore sensors en as inisieerders en reguleerders van antigeen-spesifieke immuun reaksies. mDSe het `n besonderse funksie om naïewe T limfosiete teinisieer en so die verworwe immune reaksies te aktiveer. pDSe is primêre produseerders van tipe 1 Interferon wat `n rol speel in anti-virale immuniteit. In die studie is beide die pDSe en mDSe van Suid- Afrikaners met chroniese MIV-1 infeksie (ARV en nie ARV gebruikers) met of sonder TB siekte vergelyk met ooreenstemmende MIV-1 negative kontroles. Soortgelyk aan CD4 T limfosiete, was beide die pDSe en mDSe beduidend verminder tydens `n MIV-1 infeksie (die verlaging in pDSe, mDSe en CD4 T limfosiete was onderskeidelik 63% (p 0.001), 80% (p 0.001) en 31% (p 0.01). Terselfdertyd is `n verhoogde vlak van algemene immuun aktivering en uitputting (CD38+CD8+, PD-1+CD8+T en CD38+PD-1+CD8+ T limfosiete) waargeneem. ARV behandeling ( 1 jaar) het nie gelei tot die herstel in DSe getalle alhoewel die studie `n beduidende vermeerdering in CD4 T limfosiete waargeneem het (CD4 T limfosiet vermeerdering van 89% (p 0.01), die verhogingwas nie voldoende nie). TB mede-infeksie het nie die vermindering van DSe vererger nie. Fenotipiese karakterising van die DS populasie in sirkulasie tydens MIV-1 infeksie mag die onderliggende rede vir die verlaging aandui. Fenotipiese profilering deur multi-parametriese vloeisitrometrie het ingesluit merkers van aktivering (CD86, CD80 en CD60L), maturasie (CD83), seldood (TNF-R2, FAS, FASL en TRAIL R1-R4) en chemotaksiese (CCR5, CCR7, CCR9 en CXCR6). MIV-1 infeksie was geassosieer met beduidende hoër persentasie van CD86+mDSe wat moontlik vroeë maturasie of transisie na die sekondêre limfoïedeweefsel aandui. Die frekwensie van die CD86+mDSe subpopulasie normaliseer tydens ARV terapie. MIV-1 infeksie het ook `n invloed op die distribusie van TNF-R2+pDSe en TNFR2 +mDSe gehad. Verhoogde TNF-R2 uitdrukking in beide DS populasies mag moontlik getuig van `n verhoogde oorlewings funksie.Op `n funksionele vlak het DSe van MIV-1 geinfekteerde individue reaksie tot TLR-L stimulasie getoon en in sommige gevalle was die reaksie hoër as in MIV-1 negatiewe individue. `n Beduidende hoër frekwensie van TNF-R2+pDSe, IFN- +pDSe, TNF +mDSe was waargeneem in heel bloed TLR-L kulture van MIV-1 geinfekteerde individue (TNF-R2+pDSe: LPS (p = 0.002) and R848 (p = 0.01), IFN- +pDSe: R848 (p = 0.04), TNF +mDSe: LPS (p = 0.003)) terwyl die heel bloed kulture van die ARV studie groep in die algemeen normalisering getoon het. In sekere gevalle het ARV terapie reaksies verlaag tot vlakke beduidend laer as die van die kontrole studie groep (i.e.TNF-R2+pDSe and TNF-R2+mDSe met CpG ODN stimulasie). In kontras, `n beduidende laer frekwensie van IL12p40+mDSe is opgemerk gedurende MIV-1 infeksie (p = 0.02). TLR-L kulture van die ARV studie groep het normalisering van die IL12p40+mDSe frekwensie getoon. Behandeling met die immunomodulerende VIP peptied het `n verlaging in IL12p40+mDSe vlakke geinduseer wat laer was as die van die kontrole groep. Normalisering van die IL12p40+mDSe vlakke is waargeeem in die TLR-L kulture van die ARV studie groep. Die frekwensie van TNF +pDSe in TLR-L heel bloed kulture was soortgelyk tussen die MIV-1 negatiewe, onbehandelde and behandelde MIV-1 geinfekteerde studie groepe. `n Beduidende verlaagde frekwensie was waargeneem in hierdie studie groepe tydens VIP behandeling. Hierdie data wys op unieke fenotipiese en funksionele veranderinge in die DS populasies tydens chroniese MIV-1 infeksie wat`n moontlik potensiele teiken vir immunoterapeutiese intervensie kan wees