21 research outputs found

    Location of the Zeros of Certain Complex-Valued Harmonic Polynomials

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    Finding an approximate region containing all the zeros of analytic polynomials is a well-studied problem. But the numb er of the zeros and regions containing all the zeros of complex-valued harmonic polynomials is relatively a fresh research area. It is well known that all the zeros of analytic trinomials are enclosed in some annular sectors that take into account the magnitude of the coefficients. Following Kennedy and Dehmer, we provide the zero inclusion regions of all the zeros of complex-valued harmonic polynomials in general, and in particular, we bound all the zeros of some families of harmonic trinomials in a certain annular region.Comment: 8 page

    Zeros of a two-parameter family of harmonic quadrinomials

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    In this paper, we determine the number of zeros and the zero inclusion regions of a two-parameter family of harmonic quadrinomials. We also determine a curve that separates sensepreserving and sense-reversing regions for these families of quadrinomials. Our work makes practical and effective use of the work of Wilmshurst, Khavinson, Dehmer, and also Bezout’s Theorem in the plane

    Prevalence of urinary schistosomiasis and associated risk factors among Abobo Primary School children in Gambella Regional State, southwestern Ethiopia: a cross sectional study

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    BACKGROUND: In Ethiopia, urinary schistosomiasis caused by Schistosoma haematobium has been known to be endemic in several lowland areas of the country where it causes considerable public health problems, mainly among school-age children. However, information on recent magnitude and risk factors of the disease is lacking, particularly for Gambella area. Therefore, this study aimed to assess the prevalence of urinary schistosomiasis and associated risk factors among Abobo Primary School children in Gambella, southwestern Ethiopia. METHODS: A cross-sectional study involving 304 school children was conducted in Abobo Primary School, Gambella Regional State, southwestern Ethiopia, from February to June 2014. Ten ml of urine sample was collected from each study participant and processed for microscopic examination by the urine filtration method; egg load for positive individuals was determined per 10 ml of urine. Data on socio-demographic characteristics and risk factors were collected using an interview-based questionnaire. The data were entered into and analyzed with SPSS version 20. Logistic regression and odds ratio were used to measure association and strength between variables, respectively. P-value < 0.05 at 95% CI was considered as statistically significant. RESULTS: The prevalence of urinary schistosomiasis was 35.9% (109/ 304) with a mean egg intensity of 8.76 per 10 ml of urine. Being male [AOR (95%CI) = 2.15(1.31, 3.52)], having father as a farmer [AOR (95%CI) = 1.96(1.19, 3.22)] and children living apart from parents [AOR (95% CI): 3.09 (1.14, 8.4)] were significantly associated with urinary schistosomiasis. CONCLUSION: The present study area in Gambella Regional State, southwestern Ethiopia, represents moderate-risk community for urinary schistosomiasis. Sex, father’s occupation and living apart from parents were found to be associated with infection. Treatment of all school-age children and fishermen is required once every 2 years until the prevalence of infection falls below the level of public health importance. It is also recommended to complement praziquantel treatment with supplementary measures such as provision of sanitation facilities and health education
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