This collection is made up of electronic theses and dissertations produced by post graduate students from Faculty of Sciences https://repository.biust.ac.bw/handle/123456789/34 2026-06-17T17:55:12Z 2026-06-17T17:55:12Z Mlambo, Shaw https://repository.biust.ac.bw/handle/123456789/747 2026-06-03T13:22:37Z 2025-09-01T00:00:00Z

Physiological and ecological responses of the larger grain borer, Prostephanus truncatus (Horn), to changing environments: implications for its population dynamics and management Mlambo, Shaw The rapid change in environments owing to anthropogenic activities and climate change has reshaped the geographical range and status of different insect pests of economic importance. Further, the mechanisms by which conspecific and allospecific species phenotypes vary and how that influences species adaptation in novel environments are poorly understood. The larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), is one of the quarantine pests which poses serious threats to stored maize and dried cassava tubers and has continued to expand its ranges in Africa. However, physiological and ecological data required to map the dispersal pathways and factors limiting geographical distribution of such pests in diverse environments are largely understudied. A combination of literature reviews, field (questionnaire survey and pest monitoring through pheromone baited traps) and laboratory studies were conducted to determine (i) the presence and geographical range of P. truncatus in Botswana (Chapter 2), (ii) local farmers’ knowledge, practices and perceptions on cereal postharvest management including the efficacy of current storage technologies against P. truncatus (Chapter 3), (iii) the drivers and implications of P. truncatus and Spodoptera frugiperda biological invasions in Africa (Chapter 4), (iv) effects of increasing temperatures on the transgenerational (Chapter 5) and intergenerational (Chapter 6) responses of P. truncatus, (v) feeding rates and effects of maternal host preferences on progeny fitness (Chapter 7) and (vi) effects of intra- an interspecific competition on P. truncatus’ physiological and ecological performance (Chapter 8). Standardised physiological (critical thermal maxima [CTmax], critical thermal minima [CTmin], heat knockdown time [HKDT], upper lethal temperatures [ULTs]) and ecological performance (% maize grain damage, % grain weight loss, progeny production, % insect feeding dust) traits were measured under controlled temperature and relative humidity conditions in climate chambers. Results confirmed, for the first time, the presence of P. truncatus in Botswana, but its distribution is still patchy. Although the pest seems not yet well-established inland, the current farmer practices dominated by use of botanical pesticides makes them vulnerable if P. truncatus was to become dominant. Lack of information and awareness of the dangers that P. truncatus pose and lack of improved grain storage facilities further expose local smallholder farmers to this threat. Laboratory assays showed behaviourally plastic responses to increased temperatures and varying xvii hosts. First, trait-dependent thermal plasticity responses are passed on to offspring through transgenerational and intergenerational plastic physiological responses which mediate P. truncatus progeny fitness. Alongside, maternal experiences or decisions by offspring through transgenerational plasticity act as signals for adaptation to a host. Ecological performance of P. truncatus was high at 25 and 30℃ in response to temperature suggesting high pest activity under elevated temperature conditions. This may mean that P. truncatus poses serious threats to food security with increasing temperatures under climate change. However, damage was highly suppressed at higher suboptimal temperatures of 35℃. Prostephanus truncatus failed to survive on mopane wood suggesting that the wood may not be a suitable host for the pest. The study shows P. truncatus physiological adaptative responses to changes in the environment and climate and calls for concerted efforts to monitor the pest inland, forewarn farmers of the dangers of the pest and train them on appropriate efficacious grain storage technologies to manage the pest. This work contributes insights into the ecology and physiology of P. truncatus, which are important in developing models for early warning and control, as well as integrated national and regional pest management strategies against the pest. Thesis (PhD Biological Sciences and Biotechnology)--Botswana International University of Science and Technology, 2025

2025-09-01T00:00:00Z Oluyede, Broderick Mdlongwa, Precious Makubate, Boikanyo Huang, Shujiao https://repository.biust.ac.bw/handle/123456789/734 2026-03-16T10:19:20Z 2019-01-01T00:00:00Z

The Burr-Weibull Power Series Class of Distributions Oluyede, Broderick; Mdlongwa, Precious; Makubate, Boikanyo; Huang, Shujiao A new generalized class of distributions called the Burr-Weibull Power Series (BWPS) class of distributions is developed and explored. This class of distributions generalizes the Burr power series and Weibull power series classes of distributions, respectively. A special model of the BWPS class of distributions, the new Burr-Weibull Poisson (BWP) distri- bution is considered and some of its mathematical properties are obtained. The BWP distribution contains several new and well known sub-models, including Burr-Weibull, Burr- exponential Poisson, Burr-exponential, Burr-Rayleigh Poisson, Burr-Rayleigh, Burr-Poisson, Burr, Lomax-exponential Poisson, Lomax-Weibull, Lomax-exponential, Lomax-Rayleigh, Lomax-Poisson, Lomax, Weibull, Rayleigh and exponential distributions. Maximum likeli- hood estimation technique is used to estimate the model parameters followed by a Monte Carlo simulation study. Finally an application of the BWP model to a real data set is presented to illustrate the usefulness of the proposed class of distributions

2019-01-01T00:00:00Z Oluyede, Broderick Yang, Tiantian Makubate, Boikanyo https://repository.biust.ac.bw/handle/123456789/733 2026-03-16T10:17:19Z 2016-01-01T00:00:00Z

A New Class of Generalized Power Lindley Distribution with Applications to Lifetime DataApplications to Lifetime Data Oluyede, Broderick; Yang, Tiantian; Makubate, Boikanyo In this paper, a new class of generalized distribution called the Kumaraswamy Power Lindley (KPL) distribution is proposed and studied. This class of distributions con- tains the Kumaraswamy Lindley (KL), exponentiated power Lindley (EPL), power Lindley (PL), generalized or exponentiated Lindley (GL), and Lindley (L) distributions as special cases. Series expansion of the density is obtained. Statistical properties of this class of distributions, including hazard function, reverse hazard function, monotonicity property, shapes, moments, reliability, quantile function, mean deviations, Bonferroni and Lorenz curves, entropy and Fisher information are derived. Method of maximum likelihood is used to estimate the parameters of this new class of distributions. Finally, a real data example is discussed to illustrate the applicability of this class of distribution.

2016-01-01T00:00:00Z Habtamu Bayissa, Yadeta https://repository.biust.ac.bw/handle/123456789/731 2026-03-16T09:43:32Z 2025-06-01T00:00:00Z

Magnetic drug targeting phenomena during non- Newtonian flow in the microvessel with time- Fractional derivative Habtamu Bayissa, Yadeta Cancer and cardiovascular disease are the leading causes of death worldwide incurring substantial medical costs and care and become a potential barrier to average life expectancy. Several treatment options available have considerable side effects and often are not sufficient for curative treatment. Most challenges include targeting non-specifically, poor pharmacokinetic characteristics drugs arising from poor solubility, stability, and toxicity, inefficacy and limited bio-distribution. Recently, with the advancement of nanotechnology, treatment options such as magnetic drug targeting (MDT) through the application of magnetic nanoparticles (MNPs) treatment have significantly changed the paradigm of cancer treatment due to minimum side effects and high efficacy. This research aims at theoretical analysis to examine the efficacy of the accumulation of drug carrier magnetic nanoparticles influenced by biophysical parameters near the diseased region during magnetic drug targeting. In this study, the time fractional derivatives of blood flow and factors governing the transport of drug carrier nanoparticles such as particle – particle interaction, Saffman uplift force, size and shape of carrier particles, permeability of the vessel, magnetic and viscous forces are considered. The conclusion drawn from the study shows that spherical shaped drugs carrying magnetic nanoparticles are more prominent to be targeted to the tumor region than other non-spherical shaped drugs carrying magnetic nanoparticles. Capture efficiency of the drug-carrier particles is improved with increase in the magnetization, and radius of carrier particles as both increase the magnetic force among the magnet and Drug-carrier particles. A decrease in Darcy number, Reynolds number, and tumor magnet distance decreases the total volume fraction of nanoparticles. Total volume fraction of magnetic nanoparticles decreases with increase in pulsatile frequency, Casson parameter and Hematocrit parameter. The velocity of blood and velocity of magnetic nanoparticles are boosted with enhancement in the Darcy number and Jeffrey fluid parameter, which shows an important application to the therapy of atherosclerosis. The flow resistance increases with an increase in stenosis height and Hartman number. The present study will help biomedical engineers and nanomedicine researchers develop magnetic devices and the next generation of drug carrier particles to treat cancerous tumors. Dissertation (PhD in Mathematics)---Botswana International University of Science and Technology, 2025

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