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Item An efficient numerical method for pricing double-barrieroptions on an underlying stock governed by a fractal stochastic process(MDPI, 2023) Nuugulu, Samuel Megameno; Gideon, Frednard; Patidar, Kailash C.After the discovery of the fractal structures of financial markets, enormous effort has been dedicated to finding accurate and stable numerical schemes to solve fractional Black-Scholes partial differential equations. This work, therefore, proposes a numerical scheme for pricing double-barrier options, written on an underlying stock whose dynamics are governed by a non-standard fractal stochastic process. The resultant model is time-fractional and is herein referred to as a time-fractional Black-Scholes model. The presence of the time-fractional derivative helps to capture the time-decaying effects of the underlying stock while capturing the globalized change in underlying prices and barriers. In this paper, we present the construction of the proposed scheme, analyse it in terms of its stability and convergence, and present two numerical examples of pricing double knock-in barrier-option problems. The results suggest that the proposed scheme is unconditionally stable and convergent with order O(h2 + k2).Item Soil ingestion, nutrition and the seasonality of anthrax in herbivores of Etosha National Park(Ecological society of America, 2013) Turner, Wendy C.; Imologhome, Peace; Havarua, Zepee; Kaaya, G.P.; Mfune, John K.; Getz, W.M.Anthrax, caused by the bacterium Bacillus anthracis , is a seasonally occurring infectious disease affecting primarily herbivorous wildlife and livestock. The seasonality of anthrax outbreaks varies among locations, making it difficult to develop a single consistent ecological description of this disease. Over 44 years of mortality surveillance, most anthrax cases in Etosha National Park, Namibia are observed in the wet season, although elephants have an anthrax mortality peak in the dry season. Focusing on three host species (plains zebra, Equus quagga ; African elephant, Loxodonta africana ; and springbok, Antidorcas marsupialis ) occupying the endemic anthrax area of Etosha National Park, Namibia, we tested two commonly posited causes of anthrax seasonality in herbivores: increased pathogen exposure due to greater soil contact, and increased host susceptibility due to seasonal nutritional stress. These hypotheses were assessed using fecal sampling and measurement of the percentage of fecal silicates as an index of soil ingestion and fecal nitrogen, phosphorus and crude fiber as nutritional indices. Nutritional quality for all three species was higher in wet than dry seasons. Comparing among wet seasons, nutritional indices showed either a decline in nutrition with increasing rainfall or no significant pattern. All three species had greater soil ingestion in the wet season than the dry season. Higher soil contact during the anthrax peak suggests that anthrax seasonality may in part be due to heightened exposure to B. anthracis in wet seasons, for zebra and springbok. Elephant anthrax deaths do not correspond with the season of increased soil ingestion or grazing, suggesting that other behavioral mechanisms may overshadow foraging-based risk factors for this species. Nutritional stress is unlikely the primary causative factor in wet season anthrax systems, although nutritional stress sufficient to reduce resistance is difficult to assess non-invasively in wild herbivores. In contrast, increased soil ingestion may be an important predisposing factor for wet season anthrax outbreaks. Ultimately, the amount of soil ingested and its importance in the transmission of soil-borne pathogens will vary based on foraging behaviors, intake rates, grassland structure and on the likelihood that foraging areas intersect with pathogen aggregations in the environmentItem Exploring the relationship between HIV and alcohol use in a remote Namibian mining community(AJAR, 2009) Lightfoot, ElizabethIn southern Africa, the use of alcohol is increasingly seen as creating a context of risk for HIV transmission. This qualitative study investigates the links between alcohol use and higher-risk sexual behaviours in a remote southern Namibian mining-town community. Using data from six focus groups and 16 in-depth interviews conducted in 2008, the researchers investigated knowledge of the link between alcohol consumption and HIV risk, focusing on the specific mechanisms related to drinking and higher-risk sexual behaviours. Although know!edga regarding HIV and alcohol was high among the mineworkers and other community members, the social structure of a remote mining town appears to lead to high levels of alcohol use and higher-risk sexual behaviours. The heavy use of alcohol acts as an accelerant to these behaviours, including as a source of fortitude for those with an intention to engage in casual sexual partnerships or multiple concurrent partnerships, and as a cause for those behaviours for people who may otherwise intend to avoid them. The findings suggest a need for HIV-prevention programmes that focus more holistically on HIV and AIDS and alcohol use, as well as the need for structural changes to mining-town communities in order to reduce the likelihood of both heavy alcohol use as well as a high prevalence of higher-risk sexual behaviours.Item Youth and Culture in Namibia(1998) Maree, MarethaBACKGROUND ON NAMIBIA Namibia is the last colony in Africa to attain Independence. The Republic of Namibia, lying across the Tropic of Capricorn, has a population of about 1.8 million and covers an area of 824.292 sq km. It is bordered by South Africa in the south, by Botswana on the east and Angola on the north, while the narrow Caprivi Strip in north east extends Namibia's borders to the Zambezi river and a short border with Zambia. The name Namibia was officially adopted by the United Nations in 1968. lt replaced the colonial name of ' South West Africa'. The name derives from one of the oldest deserts in the world, the Namib. The desert forms a narrow plain 65-16km wide and extending 1 600km along the coast, separating the rest of the country from the south Atlantic Ocean. The fine sand of Namib forming huge sand dunes cover one fifth of the country. Namibia's major resource, diamond and uranium, is to be found in the fine sand of the Namib desert. However, the area is almost devoid of vegetation and therefore near to uninhabitable. The eastern parts of Namibia is covered by a semi-desert, the Kalahari, were there is some vegetation. In Ovamboland, the northern parts ofthe Kalahari, crop cultivation is possible, due to a network of watercourses known as 'oshanas'. In between the Namib and the Kalahari deserts lie the Central Plateau with an average elevation of 11 OOm above sealeveL It covers one half of the country. "The Plateau stretching the full length of the country, is Namibia's most fertile area and thus most suitable for human settlement. In its northern parts, the Plateau is suitable mostly for cattle-rearing but also for crop cultivation on a limited scale. The southern part is much dryer, covered with shrub steppe and it is unsuitable for anything but cattle, goat and/or sheep-rearing. Average annual rainfall is 270mm and droughts are frequent. Namibia has the driest climate south of Sahara." (Strand: 1991 ). The implication of the above mentioned is that vineyards cannabis coca plant or opium poppies is not cultivated in Namibia, and that all substances of abuse are imported.