Department of Mathematics

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Browsing Department of Mathematics by Author "Chikamai, Lucy W."

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    On derivation of the probability of occurrence of an epidemic with application to HIV/AIDS spread given tuberculosis co-infections in the presence of treatment
    (Science Publishing Group, 2017-08-22) Simwa, Richard Onyino; Muhati, Nelson L.; Chikamai, Lucy W.
    Human Immunodeficiency Virus (HIV) and Mycobacterium Tuberculosis (TB) infections are two major world’s public health problems especially in developing countries. Worldwide, 13% of TB cases are estimated to be co-infected with HIV and about a third of 33 million people living with HIV are infected with the bacterium that causes TB. Deterministic models are derived and applied to estimate the basic reproduction number of HIV and TB co-infection as a single output value by treating each of the parameter input as a constant value. In this paper the basic reproduction number is modeled as a random variable, then the probability that there will bean epidemic, is derived and computed. In particular it is shown that for the sub-Saharan region, the probability of the epidemic occurring is 7.9%, as expected since an epidemic is generally a rare event. This research, thus develops the methodology for the computation of the probability of occurrence of an epidemic, which is useful for the public health policy formulation.
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    Some Irreducible 2-Modular Codes invariant Under The Symplectic Group S6(2)
    (GLASNIK MATEMATIˇ CKI, 2014-01-01) Chikamai, Lucy W.; Moori, Jamshid; Rodrigues, Bernardo G.
    We examine all non-trivial binary codes and designs obtained from the 2-modular primitive permutation representations of degrees up to 135 of the simple projective special symplectic group S6(2). The submodule lattice of the permutation modules, together with a comprehensive description of each code including the weight enumerator, the automorphism group, and the action of S6(2) is given. By considering the structures of the stabilizers of several codewords we attempt to gain an insight into the nature of some classes of codewords in particular those of minimum weight.
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    Stability bifurcation Analysis of a fishery model with nonlinear variation in market price
    (HIKARI Ltd: Applied Mathematical Sciences, 2018-01-01) Makwata, Harun Omukuba; Wasike, Adu A.M.; Chikamai, Lucy W.
    Stability bifurcation Analysis of a fishery model with nonlinear variation in market price We develop a fishery model with price dependent harvesting by formulating a system of three differential equations describing its dynamics. Assuming that the price of the harvested fish on the market evolves relatively faster than the evolution of the fish stock and the fishing effort, we apply approximate aggregation to reduce the system of equations from three to two. From the stability analysis of the aggregated model, we show the co-existence of three strictly positive equilibria where two are stable and are separated by a saddle. The two stable equilibtia rep- resent two kinds of fishery namey; an over-exploited fishery where the fishery supports a large economic activity but risks extinction and an under-exploited fishery where the stock is maintained at a large level far from extinction but the fishery only supports a small economic activity.
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    Suborbital Graphs and their Properties for ordered Triples in An (n = 5, 6, 7) Through Rank and Subdegree Determination
    (International Journal of Engineering and Mathematical Sciences, 2016-06-01) Ndarinyo, Cedric W.; Marani, vincent Nyongesa; Chikamai, Lucy W.; Andanje, Mulambula
    In this paper, through computation of the rank and subdegrees of alternating group An (n-5,6,7) on ordered triples we construct the suborbital graphs corresponding to the suborbits of these triples. When An(n ≥ 5) acts on ordered pairs the suborbital graphs corresponding to the non-trivial suborbits are found to be disconnected. Further, we investigate properties of the suborbital graphs constructed.