School of Biological, Physical, Mathematics & Actuarial Sciences
http://ir.jooust.ac.ke/handle/123456789/266
2024-03-28T21:44:43ZCorrelation Between the Degree of Alignment and Opto-Piezoelectric Properties of Cellulose Nanocrystals Fabricated From Water Hyacynth
http://ir.jooust.ac.ke/handle/123456789/12139
Correlation Between the Degree of Alignment and Opto-Piezoelectric Properties of Cellulose Nanocrystals Fabricated From Water Hyacynth
Adem, Jack Abibo
Cellulose nanomaterials have recently continued to attract higher attention in the current research output, due to their extremely excellent mechanical, optical as well as electrical properties. Their sustainability coupled with good structural and morphological properties have made them become a great resource in the construction of both active and passive components in the electronics sector. Interestingly, water hyacinth, a serious environmental threat in Lake Victoria and other water bodies globally, is a rich source of this novel material. This research study has been dedicated to find out the correlation between the degree of alignment and the piezoelectric effect of cellulose nanocrystals fabricated from water hyacinth. The CNCs were synthesized by a rigorous acid hydrolysis using varied acids, concentration, temperature and time and the effects of these parameters on the opto-structural properties of the resultant films investigated using UV Visspectrophotometer, fluorescence spectrophotometer and XRD technique.Further, the Urbach energies have been calculated and found to increase while the optical band gap energies found to decrease with increase in hydrolysis temperature. From a plot of Eg verses Eu, the optical band gap energy of the CNCs when there was no disorder in their microstructure was found to be ~5.43 eV. Further, it has been shown that the Urbach energy is absent when hydrolysis process is done at 14.23oC. Additionally, the piezoelectric effect of the electric field assisted convective
shear assembled CNCs has been systematically studied and the effect of the applied voltage and the frequency mapped. The sensitivity of fabricated sensors was measured using the fabricated measurement setup. From the study, a high degree of CNC orientation in the films has been found to be a key characteristic for the piezoelectric response. The amount of applied voltage and the frequency have been found to increase the degree of the orientation/alignment of the CNCs within the films hence leading to enhanced piezoelectric response. This is because the orientation of crystalline CNC regions inside the films led to a remarkable increase of piezoelectric effect as a result of the large piezoelectric coefficient of the CNCs. From the study, it was clear that functional piezoelectric sensors can be fabricated from CNF films and thus, the results obtained suggests that CNC films are suitable sensor materials for applications in different fields including electronics, biomedical diagnostics and material sciences.
2023-01-01T00:00:00ZEffect of Pollution Gradient on Sediment Bacterial Composition and Potential Pathogens in Urbanization-Impacted Streams Draining into Lake Victoria
http://ir.jooust.ac.ke/handle/123456789/12114
Effect of Pollution Gradient on Sediment Bacterial Composition and Potential Pathogens in Urbanization-Impacted Streams Draining into Lake Victoria
Achieng’, Odhiambo K.
Despite urban rivers/streams draining into Lake Victoria suffering from urbanization-
linked anthropogenic pollution, little is known about their microbiome diversity and structure, or
how they respond to intensive anthropogenic inputs. This study conducted a comprehensive
analysis of the spatial bacterial community distribution in the sediments of Kisat and Auji streams,
that flows through Kisumu City into Lake Victoria's Winam Gulf. Specifically, the study: i) used
16S rRNA gene-based Illumina MiSeq sequencing to determine the diversity and abundance of
sediment bacterial communities along the stream catchment impacted by varying levels of
urbanisation; ii) determined the presence of potential pathogens and the predicted functional
profiles of the sediment bacterial communities in the river to establish their role in the ecosystem,
and (iii) identified the key environmental factors (nutritional factors and heavy metals) influencing
compositional variations in these communities. The study adopted a stratified purposive sampling,
where 22 sediment samples were randomly collected from Lower, Mid and Upper catchment of
Auji and Kisat streams, stratified as highly, moderate and non-urbanized zones, respectively, based
on land use patterns. Results showed that polluted mid and lower catchment zones stream
sediments were highly enriched (p < 0.05) with Actinobacteria and Proteobacteria, and potential
pathogen groups such Corynebacterium, Staphylococcus, Cutibacterium, Turicella, Acinetobacter
and Micrococcus, including enterics such as Faecalibacterium, Escherichia, Klebsiella,
Enterococcus, Prevotella, Legionella, Vibrio and Salmonella. Further, Phylogenetic Investigation
of Communities by Reconstruction of Unobserved States (PICRUSt) analysis revealed enrichment
of genes associated with carbon and nitrogen metabolism and disease pathogenesis and
virulence in the lower and mid catchment zones stream sediment. Physicochemical analyses also
showed that the highly urbanized mid and lower stream catchment zones had significantly higher
(p < 0.05) total organic carbon (TOC), total nitrogen (TN), and total phosphorous (TP) content,
including severely pollution with toxic heavy metals such as lead (Pb), cadmium (Cd), and copper
(Cu) than the less urbanized upper catchment zone. Multivariate analysis suggested that TOC, Pb,
Cd, TN, pH and Cr were the significant drivers (p < 0.01) of spatial variation in community
structure, with Pb, TOC and Cd content being most influential sediment properties (p < 0.01).
Overall, these results suggest urban pollution significantly affects the stream sediment microbiome
and that the current waste management in Kisumu City is insufficient for the protection of public
health and aquatic ecosystems. Therefore, proactive and sustainable urban waste management
strategies are needed as the city undergoes rapid urbanization.
2022-01-01T00:00:00ZOn Continuity and Separability in Bitopological Spaces
http://ir.jooust.ac.ke/handle/123456789/12100
On Continuity and Separability in Bitopological Spaces
Ogola, Blasus
Many studies have been conducted on properties of bitopological spaces and aspects of continuity over a long period of time and different results have been obtained so far. However, pointwise characterization of various aspects of continuity has not been done in bitopological spaces. Moreover, our work is aiming at establishing particular separation criteria for bitopological and spaces where N > 2. This therefore calls for an in depth study of continuity and separability in bitopological spaces. The objectives of the study were to: characterize notion of ij-continuity in bitopological spaces; establish separation criteria for bitopological spaces via ij-continuity; and determine extensions of continuity and separability in N-topological spaces. The methodologies involved use of criterion for continuity, criteria for inverse continuity, separation axioms and conditions for normality. The results showed that various continuity notions such as p_, θ_ and pd exist in bitopological spaces. For separation criteria, the results showed that if bitopological spaces are T0, T1, T2 and T52 properties are both topological and hereditary. For extension and separability in N-topological spaces results indicated that properties can be naturally extended to N-topological spaces. The results obtained are useful in studying topological deformations such as stretching which is fundamental in understanding the shape and structure of the universe and formulations of real functions and topological mappings. Our results also help in deep understanding of molecular biology more particularly on DNA structure. Our results also play a great role in understanding the applications of computer topology such as line, ring, star and hybrid topologies.
2023-01-01T00:00:00ZRelationship Between Internal Psychological States and Indulgence in Behaviour Problems of Secondary School Students in Kenya.
http://ir.jooust.ac.ke/handle/123456789/11943
Relationship Between Internal Psychological States and Indulgence in Behaviour Problems of Secondary School Students in Kenya.
Aomo., Agwaya, John
Behavioural problems among students are a challenge in most Kenyan schools and the occurrence of behavior problems among students has been reported in Kisii County. Since most of the previous studies have focused on external factors that influence indulgence in behavior problems among students and scanty information in literature on internal psychological states necessitated the present study. The purpose of this study was to establish the relationship between internal psychological states and indulgence in behaviour problems among secondary school students in Kisii County of Kenya . The study objectives were; To establish the relationship between personality subtypes, and student indulgence in behaviour problems, To determine the relationship between students' self-esteem and indulgence in behavior problems, to determine relationship between students self-efficacy and indulgence in behaviour problems and to find out the relationship between locus of control and student indulgence in behaviour problems. The study was informed by Eysencks theory of criminal personality, theory of planned behaviuor and Person centred theory. A Concurrent Triangulation Design within the Mixed Method approach was adopted. The target population was 11479 form three students drawn from three Sub Counties; Sameta, Kisii Central and Gucha South Sub Counties. A sample size of 386 students was involved in the study. The Eysenck Personality Questionnaire, Self-esteem scale, Self-Efficacy Scale, Locus of Control Scale and Indulgence in Behaviour Problem Questionnaire were used to collect quantitative data for the study. Interview schedule were used to collect qualitative data. Reliability of the instruments were determined using internal consistency and an index of 0.838 was reported. Validity of the instruments were ensured by expert judgement by University lectures. The study adopted stratified sampling technique for student respondents as simple random technique was used to draw participants for interview schedule. Quantitative data was analyzed by using inferential statistics, which included Analysis of Variance (ANOVA) and Pearson product moment correlation coefficient to test the hypotheses. Qualitative data was analyzed by using thematic analysis. The findings indicated that there was a statistically significant difference (at the p<0.05 level) in students' indulgence in behaviour problems scores for the three personality subtypes [F (2, 344) =1181.25, p<0.05]. That is, the indulgence to behaviour problems mean score for extroverted students was significantly different from the mean score of introverted students and neurotic. The mean indulgence in behaviour problem for inrrovert and neurotic students also differed significantly from each other. The study established a plausible negative (r = -0.564) correlation between students' self-esteem and indulgence in behaviour problems. The analysis revealed a highly significant (p< 0.05) negative relationship between the two variables, with high level of self-esteem associated with low level of indulgence in behaviour problems. The study shows that there was a strong negative (n=347, r = -0.612) but highly significant (p <0.05) correlation between students' self-efficacy and students' indulgence in behaviour problems with high level of self-efficacy associated with low level of indulgence in behaviour problems. The study also revealed that there was a statistically significant difference (p<0.05) in students' indulgence in behaviour scores for the three locus of control [F (2, 344)
=40387.97, p<0.05] The teacher counselors should identify appropriate therapy techniques for the students at risk of indulgence in behavior problems.
2017-01-01T00:00:00ZEstimation of volatility using mean reverting European-logistic type option pricing model.
http://ir.jooust.ac.ke/handle/123456789/11942
Estimation of volatility using mean reverting European-logistic type option pricing model.
Brian, Oduor, Daniel
Mean reversion is a mathematical concept that is frequently and widely used in stock investing, modeling interest rates and modeling commodities. In particular there is consensus that a commodity price cannot increase exponentially but rather revert to their equilibrium mean levels. The field of mean reversion has been considered a natural choice of option contract in the essence of its concepts and assumptions that both stock's high and low prices are temporary and that stock's price will tend to move to average price over time. Oldrich Vasicek developed a Vasicek model used in valuation of interest rates and that was adopted for credit markets. The concept of mean reverting processes that has been discussed in financial literature has mainly been derived from mean reverting geometric Brownian motion. However, mean reverting logistic Brownian motion has not been discussed in any financial literature. In this study we have used the knowledge of logistic Brownian motion to develop a mean reverting logistic Brownian motion model for price process. The methodology involved analysis of mean reverting models for pricing process in particular Vasicek model. We have considered logistic Brownian motion and incorporated mean reverting process. We have applied the approach of Vasicek model to derive mean reverting logistic Brownian motion. The presence of mean reversion is tested using Dickey-Fuller test. We have finally estimated volatility using maximum likelihood estimate. The results are analyzed from historical price data collected from Nairobi Security Market. This model can be used by long-term investors to the know impact of mean reverting behavior of stocks on assets before allocating decisions on investment and profitability of trading strategies.
2016-01-01T00:00:00ZA Valuation Model for a Defined Contribution Pension Scheme Assets using a Contingent Claim
http://ir.jooust.ac.ke/handle/123456789/11939
A Valuation Model for a Defined Contribution Pension Scheme Assets using a Contingent Claim
Joshua, Were
Investment of pension assets are normally held in consideration of a financial market of different asset types such as stocks, bonds with different maturities or various financial derivatives. In recent years, two directions for funded pension systems have been taken. The first entails abolishment of the collective arrangement, and a direct move into individual pension schemes, where funding responsibility is shifted completely from sponsors to individuals. Various individual defined-contribution (DC) accounts are typical examples here. However, the DC schemes not only concentrate the risks on each individual, but also confront individuals with complex investment decisions. The second direction involves keeping the collective nature of the DB schemes, but spreading out the funding responsibility to all stakeholders (retirees, employees and sponsors). Various hybrid collective schemes are typical examples of such practices. It puts forward the question as to how risks should be allocated among stakeholders. Is one direction better than the other, or should both directions be improved? The answer to this lies in the development of a relevant contingent claim.The objective of this study is to construct a contingent claim that guarantees a specific investment return on a Defined Contribution fund .assets held.. This thesis develops a general stochastic model in a frictionless market with assumed continuous trading. Within the framework of this model we discuss the modern theory of contingent claim valuation including the known option pricing formula of Black and Scholes. We then apply t.hc Faynman-Kac representation theorem to generate the contingent claim process that allows for guaranteed investment income by solving the generated boundary value problem.This has been generalised to incorporate a further consideration of the mar• ket price of risk in a normalized gain process.A guaranteed investment income gives a member of a scheme an assured additional income generated from investments.
2017-01-01T00:00:00ZBinomial Mixtures Based on Beta Prior Distributions and their Generalizations
http://ir.jooust.ac.ke/handle/123456789/11937
Binomial Mixtures Based on Beta Prior Distributions and their Generalizations
Andrea, Otwande
A mixed distribution can be obtained when two or more distributions are combined. The integral of the product of the mixture is determined for continuous case and for the discrete the sum of the product is determined Binomial distribution is discrete distribution while beta distribution is continuous distribution. However the joint distribution of their mixture turns out to be in the form of beta distribution which is continuous. McDonald generated many generalized beta distributions that could be applicable as mixing distributions in the Binomial mixtures. Bowman and other researchers used the transformation p = e-0 to generate a large number of generalized mixing distributions. The most common prior distribution for the probability of success is classical beta distribution. However beta II distribution and its generalizations have not been used as prior distributions. Also the methods of construction of the mixtures such as direct integration and method of moments were not proved to be identical. Studies in the statistical literature concentrated on binomial mixtures but did not focus on posterior distributions and Bayesian inference. This study focused on Beta-binomial mixture whose origin dated back to the year 1948 when Skellam mixed a binomial distribution with its parameters being probability of success taking beta distribution. The objective was to construct binomial mixtures using beta prior distribution and its generalizations. Specifically it focused on proving identity of two methods of construction of binomial mixtures, construction of the binomial mixtures with parameterized beta distribution such as p = 1�0 and p = e:", differential equations of binomial mixtures using Panjor-Willmot and Hesselager's recursive models and posterior distributions were obtained. Construction of the beta-binomial mixtures involved use of special functions such as Gamma function, beta function, confluent hypergeometric function and Gauss hypergeometric function. Transforms such as generating functions and laplace transforms were applied to construct, probability distributions. To obtain differential equations the recursive models obtained from the Beta-Binomial mixtures were fitted to appropriate known models such as Panjer-Willmot and Hesselagers recursive models. This study is important as it addresses the problem of over-dispersion, a challenge which is common in modeling data that has binomial outcomes. This was achieved as the variance of the binomial mixtures obtained is theoretically larger and hence more likely to fit till' variance of the empirical data. The mixture was applied to group screening design where the varying probability of contamination was estimated, with the outcome in support of Bayesian technique than maximum likelihood technique for low values of p and vise versa for higher values of p,
2018-01-01T00:00:00ZModeling of jumps and mean reversion in the Kenyan interest rates.
http://ir.jooust.ac.ke/handle/123456789/11936
Modeling of jumps and mean reversion in the Kenyan interest rates.
Rangita, Apaka Boniface
The Black-Scholes-Merton model of 1973 has been used and improved upon by various scholars and practitioners to model stock price, interest rates, options and other financial derivatives. Derived from this model are various term structure models and their jump diffusion counterparts. In particular the pure diffusion process is one of the term structure models nested in the Clum, Karolyi, Longstaff and Sanders (CKLS) model that has not been combined with the jump processes. We therefore used the Pure diffusion model (PDP) combined with the Poisson jump process, Bernoulli jump process and mean reversion process to create new models namely; Bernoulli jump diffusion (BJD), mean reverting Bernoulli jump diffusion (MR.BJD) and Poisson jump diffusion (PJD) models. The ap• plication of interest rate models has also been mainly restricted to the developed countries, and for the first time here we study their application in Kenya. We fitted the weekly changes in the risk free 91 day Kenyan treasury bills rates rather than the rates themselves into these models. Using the Maximum likelihood estimation methodology (MLE) we esti• mated the parameters and found evidence of jumps but no evidence of mean reversion in these rates. We also found that the Poisson Jump diffusion (P JD) model outperforms the Bernoulli jump diffusion (BJD), mean reverting Bernoulli jump diffusion (MR.BJD) and the Pure diffusion (PDP) models with respect to these rates. This study may help traders in forecasting, pricing and investment decisions.
2015-01-01T00:00:00ZOn Complete Positively and Boundedness of Operators on Non- Unital C*- Algebras.
http://ir.jooust.ac.ke/handle/123456789/11935
On Complete Positively and Boundedness of Operators on Non- Unital C*- Algebras.
Karieko, Obogi, Robert
Properties of completely positive and completely bounded operators are fundamental in understanding the applications of operator theory in other fields like quantum mechanics. Up to date the question as to whether com• pletely positive operators are completely bounded has not yet been fully investigated particularly on non-unital C*-algebras. Paulsen established that completely positive operators are completely bounded on unital C*• algebras. However, his study did not focus on non-unital C*-algebras. The question which arises then is: Are completely positive operators com• pletely bounded on non-unital C*-algebras? Therefore, it is interesting to investigate completely positive and completely bounded operators on non-unital C*-algebras. The objectives of this study are to: investigate completely positive operators on non-unital C*-algebras; investigate com• pletely bounded operators on non-unital C*-algebras and establish the relationship between completely positive and completely bounded oper• ators on non-unit.al C*-algebras. The methodology involved considering C*-algebras from the known ones like B(1i), the C*-algebra of all bounded linear operators on a Hilbert space 'H. and then investigating the properties of completely positive and completely bounded operators on non-unital C*-algebras. The technical approach in this study included techniques of tensor products and the Haagerup norm which were useful in determining the norms of completely bounded operators. The results obtained from this study are applicable in quantum chemistry in estimation of ground state energy of chemical systems and in genetics to represent the DNA double helix strand using adjoints. Moreover, the results are also useful in commutator approximation and quantum error correction.
2017-01-01T00:00:00ZOpportunities of Recreational Ecotourism in Water Resources within Beach Environments of Lake Victoria.
http://ir.jooust.ac.ke/handle/123456789/11933
Opportunities of Recreational Ecotourism in Water Resources within Beach Environments of Lake Victoria.
Okungu, Jared Ouma.
Ecotourism, one of the world's biggest revenue generating industries world over, utilizes natural water resources as recreational destinations in most economies around the world. However, developing nations, including Kenya, lag behind on the industry development because of limited scientific evaluations. The study was conducted in Asat, Ogal, Usoma and Lwang'ni beaches in Victoria, Kenya, the main objective being to demonstrate chal• lenges and opportunities of recreational ecotourism in fresh water Lake Victoria shore are• as of Kisumu county. The study integrated diverse themes through the objectives: to doc• ument the physical and aesthetic status of recreational features within environments of L. Victoria; to assess water quality indicators of recreational ecotourism at the beach areas; and to determine the influence of risk perceptions on participation in water-based recrea• tionable activities. Applying case study and mixed design approach, observation data were treated with content analysis and presented by descriptions. A 12 - month water samples were collected and analyzed for physical and bio-chemical recreational quality. The re• sultant values were treated to significance test (t-test) for spatio-temporal variations. Sur• vey data attributes for risk factors were treated for significance using Kruskal-Wallis va• lidity test. Results of physical status revealed that 85. I% of the study sites constituted dry• lands, but with little facilitative amenities for recreation. Circumstances of recreationally unfriendly environments observed to be characterized by decayed organic matter, silt & sediment deposits at 43.38%; spread of algae at 23.75%; oil films and foams at 8.10%; and occupancy by heaps of solid wastes at 0.85%. Results of confirmatory water quality tests suggested that Temperature, pH, DO, E. Coli and BOD occurred within recommended recreational detection limits, but turbidity, TSS, TN and TP occurred at unfavorably high levels by 29.28%, 19.48%, 4.17%, and 3.16% respectively. Statistically significant differ• ences were confirmed to exist for mean values of all parameters during wet and dry months except for pH. Mean values of current research were compared with those of
2015/16 correspondingly. Results indicate increased trends in Turbidity, TSS, BOD, TN and E. Coli at 4.72%, 5.36%, 3.93%, 6.04% and 8.51% respectively. In all possible water• based recreational activities participation levels were observed for swimming, fishing, boating and sunbathing at a mean low of 5.9% - a close reflection of survey responses ob• tained for participation levels at 9.48%, and perception of popularity at 11.8% for similar activities. Across all study sites, there was a statistically significant effect of perceived risk factors on participation in recreationable activities. This study recommends enhancement of sanitary and aesthetically conducive waterfront environments, control of pollution sources and mitigation of impacts, and initiation and implementation of sensitization and branding programmes for potential recreationists.
2017-01-01T00:00:00Z