Posterior F-Value In Bayesian Analysis Of Variance Using Winbugs

Analysis of variance (ANOVA) is a standard method for describing and estimating heterogeneity among the means of a response variable across the levels of multiple categorical factors. In most experimental settings, ANOVA is used to test the presence of treatment effects. Frequentist approaches to making inferences about the variances of random cluster effects in hierarchical generalized linear models (HGLMs) have several limitations. These include reliance on asymptotic theory, questionable properties of classical likelihood ratio tests when pseudo-likelihood methods are used for estimation, and a failure to account for uncertainty in the estimation of features of prior distributions for model parameters. This paper compares and contrasts alternative approaches to making a specific type of inference about the variance components in an HGLM, focusing on the difference in the variance components. A Bayesian approach to making inferences about these types of differences is proposed that circumvents many of the problems associated with alternative frequentist approaches.Bayesian hypothesis testing literature on ANOVA is scant; the dominant treatment is still classical or frequentist. One impediment to adoption of Bayesian approach is lack of practical development, particularly a lack of ready-to-use formulas and algorithms. Markov Chain Monte Carlo (MCMC) and Gibbs sampling are used to obtain posterior point estimates from these posterior distributions. The 95% credible intervals (CI) were also obtained. Posterior F-values were obtained for the different priors and finally compared with that obtained using classical approach. The Bayesian test for ANOVA designs is useful to both researchers and students; both groups will get to appreciate the importance of Bayesian approach when applied to practical statistical problems. Key Words: Bayesian Analysis of Variance, Variance Components, Hierarchical Generalized Linear Models, Posterior F-value, ANOVA

Tuberculosis of the oral mucosa: Case report

There is an increase in the incidence of extra-pulmonary tuberculosis (TB) despite decline in cases of  pulmonary TB. Oral TB lesions are non-specific in their presentation and are often a forgotten differential  diagnosis in oral lesions. This report presents a previously undiagnosed case of TB whose oral lesions led to  diagnosis and treatment

Blind Naso-Endotracheal Intubation

Patients with ‘difficult endotracheal intubation’ may present for elective or emergency surgery. We present a case of a 29 year old female patient who required general anaesthesia for resection of a large mandibular osteosarcoma where the blind nasoendotracheal intubation technique was used

Evaluation of Technical Efficiency of Sweet Corn Production among Smallholder Farmers in Njoro district, Kenya

The National Agriculture Policy stresses the involvement of all stakeholders in decision making as one of the major strategies for eradicating poverty and increased productivity. Therefore, in recognition to the economic importance of horticulture to Kenya, technical efficiency of sweet corn production was evaluated to substantiate the paradox behind persistent reduction in productivity that impedes the development of the vibrant industry. A semi-structured and pre-tested questionnaire was used to collect data from smallholder producers through face-to-face interview. The census and purposive sampling methods were employed to obtain 76 respondents who were subjected to a stochastic production frontier model to estimate technical efficiency of sweet corn production. The results showed a mean efficiency score of 74% indicating that there was a 26% allowance for improvement. Land tenure with title (p≤0.05), hired labour (p≤0.05) and off-farm activities (p≤0.1) with positive effects while age (p≤0.05) and gender of the household head (p≤0.1) with negative effects on technical inefficiency. Therefore, there exists opportunity to improve efficiency in production given existing farm technologies more so if they embrace the use of family labour effectively and deterministic lawful land ownership. Besides, off-farm activities would reduce the overreliance on farming and promote higher returns by boosting on efficient resources use. Keywords: Technical, Efficiency, Farm technologies, Sweet corn, Stochastic frontie

Clinical aplications of Trioxolane derivatives

The aqueous extracts of three medicinal plants, Carissa edulis (Forssk.) Vahl (Apocynaceae), Prunus africana (Hook.f.) Kalkm (Rosaceae) and Melia azedarach L. (Meliaceae) have shown significant reduction in the replication of human cytomegalovirus (HCMV) in human embryonic lung (HEL) fibroblasts cells in vitro. Using the plaque inhibition assay for the determination of anti-viral activity, the HEL fibroblast cells cultured in 24 well plates were infected with 1 x 102 PFU 91S HCMV and treated with various concentrations of the extracts. The plaques formed were counted after 7 days incubation at 37\ub0C in 5% CO2 and the percent plaques inhibited were calculated against infected untreated control. The effective concentrations inhibiting plaque formation by 50% (EC50) was found between 40 to 80 \u3bcg/ml for all the extracts. The cell cytotoxic concentrations (CC50) for each of the three extracts, by the trypan blue exclusion test, gave a safe therapeutic index. These results have demonstrated the potential anti-viral activities of the extracts of the three medicinal plants at non-cytotoxic concentrations

Evaluation of Technical Efficiency of Rabbit Production in Buuri Sub -County, Meru County, Kenya

Current rabbit production in Buuri Sub county stands at 1.2 Metric tons of meat against a potential of 8.4 Metric tons per year. This productivity gap is wide and indicative of poor and low performance of the enterprise in rural areas of Kenya and specifically Buuri Sub County. Thus the main objective of this study was to investigate the technical efficiency of rabbit production and its contribution to household food production and family welfare under conditions of resource scarcity. The technical efficiency of rabbit production was evaluated to explain the paradox behind the low productivity of rabbit enterprises in Buuri sub-county. A multistage simple random sampling procedure was employed to get 139 respondents for the study. A semi structured and pre-tested questionnaire was used to collect data from the selected small holder rabbit producers through face to face interview of the household heads. The study used descriptive statistics for the analysis of socioeconomic and institutional attributes of the rabbit producers. The stochastic frontier production parametric method was used for the efficiency analysis. The results showed mean technical efficiencies among the rabbit farms were 36.83%. The farmers are not producing the rabbit output at minimum costs.  Further the study found that the capital is the most important rabbit output enhancing variable among all studied parameters. The Tobit model results indicated that increased access to education, trainings and credit to the farmers led to improved rabbit efficiency. More importantly county government and non-governmental agencies should make deliberate attempts for improved farmer-extension and research linkage for better technology transfer and adoption by farmers, leading to more productive rabbit enterprises hence improved incomes and thus reducing poverty level among farmers. Keywords: Technical efficiency, rabbit breeds, efficiency, rabbit keeping, backyard farming enterprises, stochastic frontie

Clinical epidemiology, diagnosis and treatment of visceral leishmaniasis in the Pokot endemic area of Uganda and Kenya.

Between 2000 and 2010, Médecins Sans Frontières diagnosed and treated 4,831 patients with visceral leishmaniasis (VL) in the Pokot region straddling the border between Uganda and Kenya. A retrospective analysis of routinely collected clinical data showed no marked seasonal or annual fluctuations. Males between 5 and 14 years of age were the most affected group. Marked splenomegaly and anemia were striking features. An rK39 antigen-based rapid diagnostic test was evaluated and found sufficiently accurate to replace the direct agglutination test and spleen aspiration as the first-line diagnostic procedure. The case-fatality rate with sodium stibogluconate as first-line treatment was low. The VL relapses were rare and often diagnosed more than 6 months post-treatment. Post-kala-azar dermal leishmaniasis was rare but likely to be underdiagnosed. The epidemiological and clinical features of VL in the Pokot area differed markedly from VL in Sudan, the main endemic focus in Africa

The Congruence between Teaching and Learning! Exploration of the Relationship between Preschool Teaching or Instructional Methods and Mathematics Performance in Lower Primary Schools in Kenya

The obstacles and difficulties hindering good performance in mathematics by Lower Primary school children seem to originate from inconsistence of instructional methods applied by teachers at the level. These methods don’t agree with the ones initially applied by the children’s teachers at preschool level. The effect of that could result in denying children a precious start to their future mathematics performance. There is a persistent indication that a discontinuity exists between pre-school learning methods and those in the lower primary schools. Teaching methods of the lower primary should be amended to make allowance for the stages of children’s development and provide opportunities to encourage children to improve in their ability to understand and apply mathematical concepts. The purpose of this study was to explore the impact of the pre-school mathematics programme on mathematics performance in the Lower Primary Schools of the Makuyu Zone, Murang’a South District. The objectives of this study were: - to investigate continuity of teaching methods from pre-school to lower primary school; and to compare the relationship between performance in mathematics of children who had had pre-school education with those who had not. This study used a descriptive survey design to achieve the set objectives. Purposive (deliberately) sampling was used to select a sample population of 60 pupils; a lottery (random choice) method of sampling was applied to get 30 teachers, whereas 10 head teachers were chosen through appointment (deliberate) sampling.  Open-ended questionnaires to collect data from the selected teachers and head teachers were applied; and for the children's responses, an interview schedule was employed. Observational checklists were also used where archival records were to apply. To test the construct validity and reliability of the research instruments, the researchers used 'split-half'.  The researchers pilot-tested the research instruments with a small representative group from the population. The data collected was analysed, using frequency counts and percentages and presentations were done in tables, bar graphs, pie charts and histograms as necessary to present a better picture of the findings. This study recommends frequent mathematics methodology seminars, workshops/in-service training for lower primary mathematics’ teachers which will guarantee effective methodological knowledge for teachers to teach mathematics effectively. Children’s learning at play should be very much emphasized. To avoid discontinuity this study recommends that in the lower primary male and female teachers should alternate to make the learners get used to male teachers. More male teachers should also get to teach in the preschool level. Keywords: Preschool; Mathematics Performance; Instructional Method

The Congruence between Teachers and Learners Perceptions! Exploration of Relationship between Teachers and Learners Perceptions and Mathematics Performance in Lower Primary Schools in Kenya

The difficulties and problems hindering good performance in mathematics by Lower Primary school children seem to emanate from teachers and learners perceptions towards mathematics learning and performance. This may be due to the fact that the methods used at lower primary don’t agree with the ones initially applied by the children’s teachers at preschool level. The effect of that could result in creating a negative perception towards math learning and performance hence denying children a precious start to their future mathematics performance. There is a persistent indication that a discontinuity exists between pre-school learning methods and those in the lower primary schools. Teaching methods of the lower primary should be amended to make allowance for the stages of children’s development and provide opportunities to encourage children to improve in their ability to understand and apply mathematical concepts. The purpose of this study was to explore the relationship between teachers and learners perceptions and mathematics performance in Lower Primary Schools of the Makuyu Zone, Murang’a South District in Kenya. The objectives of this study were: - to evaluate the teachers’ perception on the value of pre-school mathematics; and to evaluate the children’s perception with regard to mathematics learning. This study used a descriptive survey design to achieve the set objectives. Purposive (deliberately) sampling was used to select a sample population of 60 pupils; a lottery (random choice) method of sampling was applied to get 30 teachers, whereas 10 head teachers were chosen through appointment (deliberate) sampling.  Open-ended questionnaires to collect data from the selected teachers and head teachers were applied; and for the children's responses, an interview schedule was employed. Observational checklists were also used where archival records were to apply. To test the construct validity and reliability of the research instruments, the researchers used 'split-half'.  The researchers pilot-tested the research instruments with a small representative group from the population. The data collected was analysed, using frequency counts and percentages.  It was presented in tables, bar graphs, pie charts and histograms as necessary to present a better picture of the findings. This study recommends frequent mathematics methodology seminars, workshops/in-service training for lower primary mathematics’ teachers. Paid study leave/time and promotions to enhance teacher motivation and creation of positive perceptions towards teaching of mathematic which will go along way in improving mathematics performance. Keywords: Preschool; Mathematics Performance; Instructional Method