A smooth test of goodness-of-fit for the baseline hazard function in recurrent event models

Conference paperIn this paper, we formulate a smooth test of goodness-of-fit for a simple hypothesis about the baseline hazard function in recurrent-event models. The formulation is an extension of Neyman' s goodness-of-fit approach, whose score tests are obtained by embedding the null hypothesis in a larger class of hazard rate functions. Since the application is in recurrent event models , the data is dynamic.A useful feature about this test is the parametric approach that makes inference about the hazard function more efficient. To examine the finite-sample properties of this test, we used simulated data . For validation, we applied the test to a real-life recurrent event data. Results show that the test possesses better power over wide range of alternatives, when compared with similar tests of the chi-square type in the literature.In this paper, we formulate a smooth test of goodness-of-fit for a simple hypothesis about the baseline hazard function in recurrent-event models. The formulation is an extension of Neyman' s goodness-of-fit approach, whose score tests are obtained by embedding the null hypothesis in a larger class of hazard rate functions. Since the application is in recurrent event models , the data is dynamic.A useful feature about this test is the parametric approach that makes inference about the hazard function more efficient. To examine the finite-sample properties of this test, we used simulated data . For validation, we applied the test to a real-life recurrent event data. Results show that the test possesses better power over wide range of alternatives, when compared with similar tests of the chi-square type in the literature

University –Industry Partnership: meeting the challenges of the 21st century

AtricleUniversities play a crucial role in society as producers and transmitters of knowledge. In recent years the discussion whether academia can encompass a third mission of enterprise development, in addition to research and teaching, has received greater attention (Mansfield,1995;Branscomb et al, 1999; Etzkowitz & Leydesdorff, 2000). Much of the current debate on university-industry links focuses on a narrow range of activities such as spin-offs and start-ups from universities and higher education institutes, and the licensing of intellectual property. However, as many authors have noted, university-industry links embrace a much broader spectrum of activities than commercialization of intellectual property rights ( Agrawal and Henderson, 2002; Mowery and Sampat, 2003; Cohen et al, 2002;Schartinger et al, 2001). In particular, Cohen et al (2002), using the data from the Carnegie Mellon Survey of R&D performing firms in the US, highlighted that for most industries, patents and licenses were of lower importance as channels for conveying public research to industry compared to publications, conferences, informal interactions and consulting. In addition, Schartinger et al (2001) and Roessner(1993) have shown that patenting and licensing account for a low proportion of university- industry interactions when compared to other formal arrangements such as contract research or joint research agreements. 2 In this paper the interface between universities and industry is studied as a way of responding to the economic needs of society in the twenty-first century through academic entrepreneurship i.e. the variety of ways in which universities take direct part in the commercialization of knowledge through the supply of creative research and inventions. This university-industry interaction will help the industry deal with financial pressure to reduce costs and increase efficiency; increased competition and rising customer expectations. It will also enhance the ability of universities to deal with global competition in the academic market place; pressure to diversify financing sources; and rising demands from students and society for quality and relevant curricula

The role of macrophytes in the economy of the lower Sondu-Miriu river of Lake Victoria

This paper highlights the results of a 12 month's ecological study of macrophytes and their role in the economy of the lower Sondu-Miriu river of Lake Victoria. A total of 34 species of aquatic macrophytes were identified. These were grouped as emergent, floating leaved, free floating and submersed. The major community type identified were dominated by Cladium jamaicanse (Crantz) Kurk., Cyperus paprus (L.) and Cyperus latifolius (Poir). The study observed an over dependence on macrophytes by the local community for the supply of bedding, grazing fields, fuel, roofing and other building materials. The white (heart) of Typha shoot, Nile cabbage (Pistia stratiotes and a legume solanum nigrum traditionally known as "osuga" are used as vegetables by local community. The only source of protein in this arid region is the fish caught in the swamps and birds which inhabit the swamp. The swamp provides the only source of green pasture in the dry season for the animals. An export oriented economy has developed involving mat making and basket weaving with exports reaching as far as Japan. The study proposes a rational and sustainable exploitation of the littoral zone to support the adjacent rural community

Upper Abdominal Ultra-Sonography Findings in HIV Patients at Kenyatta National Hospital and the Defense Forces Memorial Hospital

Background: Easy availability, accessibility and affordability make ultra-sonography an invaluable  diagnostic tool in clinical investigation of infectious and non-infectious complications of human immunodeficiency virus (HIV).Objective: To determine the pattern of upper abdominal abnormalities in HIV infected patients at ultra-sonography and correlate with clinical presentations.Design: A descriptive cross-sectional study.Setting: Kenyatta National Hospital and the Defence Forces Memorial Hospital, Nairobi, Kenya.Subjects: HIV infected patients referred for upper abdominal sonography within the study duration of eight months.Results: Two hundred and seventy three (273) patients were included in the study. Overall, upper abdominal pain accounted for 31.9%, pyrexia of unknown origin 30.40% and general abdominal pains  27.68% of clinical indications for sonography. The main clinical indication for liver sonography was  hepatitis (45.80%) and the kidney was renal failure (66.67%). The most common liver pathology was diffuse fat infiltration at 35.71%. The most common renal pathology was renal parenchymal disease (93%). Para-aortic lymphadenopathy was present in 42.90% and ascites 25.60% of patients. Conclusion: Renal parenchymal changes (type I and II), fatty liver, intra-abdominal lymphadenopathy and gallbladder sludge are common findings in HIV infected individuals despite paucity of clinical suspicion

Banking Concentration and Financial Stability: New Evidence from a Developing Country

The policy debate on the trade-off and synergies between bank concentration and financial stability remains unresolved. Previous studies suggest two hypotheses; ‘concentration-stability’ and ‘concentration-fragility’. This paper investigated the effect of bank concentration on financial stability in Kenya using Structural Equation Modelling (SEM) for the period 1990-2017. Estimation results reveal that high concentration leads to instability of the financial system. Further, increased competition improves stability of the financial system while regulation positively affects financial stability and bank concentration. Therefore, policies that ensures less bank concentration and enhance bank competition may significantly improve financial stability. Keywords: Financial stability, Banking Fragility, Structural Equation Model JEL classification: G21, G28. DOI: 10.7176/EJBM/11-25-08 Publication date:September 30th 2019

Financial Stability in Kenya. Does Inclusive Finance Matter?

Kenya has made significant stride in financial inclusion compared to other Sub-Saharan economies. Using time series data for the period 2004 to 2017 and Structural Equation Modelling (SEM), this study seeks to investigate whether there are trade-offs or synergies between inclusive finance and financial stability. Previous evidence suggests both positive and negative effects, but evidence on emerging economies such as Kenya is clearly lacking. This can partly be attributed to scarcity of data on inclusive finance. Estimation results reveal that access and usage of financial services may foster financial stability in Kenya. Therefore, policies that enhance access and usage of financial services may boost financial stability. Keywords: Financial Inclusion, Structural Equation Model, Financial Stability JEL classification: G21, G28, O16. DOI: 10.7176/JESD/10-6-07 Publication date:March 31st 201

A copula-based approach to differential gene expression analysis

Conference paper presented in International Biometric Conference 2014Melanoma is a major public health concern in the developed world. Melanoma research has been enhanced by the introduction of microarray technology, whose main aim is to identify genes that are associated with outcomes of interest in melanoma biology and disease progression. Many statistical methods have been proposed for gene selection but so far none of them is regarded as the standard method. In addition, none of the proposed methods have applied copulas to identify genes that are associated with quantitative traits. In this study, we developed a copula-based approach to identify genes that are associated with quantitative traits in the systems biology of melanoma. To assess the statistical properties of model , we evaluated the power, the false-rejection rate and the true-rejection rate using simulated gene expression data . The model was then applied to a melanoma dataset for validation. Comparison of the copula approach with the Bayesian and other parametric approaches was performed, based on the false discovery rate (FOR) , the value of R-square and prognostic properties. It turned out that the copula model was more robust and better than the others in the selection of genes that were biologically and clinically significant.Melanoma is a major public health concern in the developed world. Melanoma research has been enhanced by the introduction of microarray technology, whose main aim is to identify genes that are associated with outcomes of interest in melanoma biology and disease progression. Many statistical methods have been proposed for gene selection but so far none of them is regarded as the standard method. In addition, none of the proposed methods have applied copulas to identify genes that are associated with quantitative traits. In this study, we developed a copula-based approach to identify genes that are associated with quantitative traits in the systems biology of melanoma. To assess the statistical properties of model , we evaluated the power, the false-rejection rate and the true-rejection rate using simulated gene expression data . The model was then applied to a melanoma dataset for validation. Comparison of the copula approach with the Bayesian and other parametric approaches was performed, based on the false discovery rate (FOR) , the value of R-square and prognostic properties. It turned out that the copula model was more robust and better than the others in the selection of genes that were biologically and clinically significant

Mathematical model for pneumonia dynamics among children

The 2012 Southern Africa mathematical sciences association Conference (SAMSA 2012)26th -29th Nov 2012There are major advances which have been made to understand the epidemiology of infectious diseases. However, more than 2 million children in the developing countries still die from pneumonia each year. The eorts to promptly detect, eectively treat and control the spread of pneumonia is possible if its dynamics is understood. In this paper,we develop a mathematical model for pneumonia among children underve years of age. The model is analyzed using the theory of ordinary dierential equations and dynamical systems. We derive the basic reproduction number, R0, analyze the stability of equilibrium points and bifurcation analysis. The results of the analysis shows that there exist a locally stable disease free equilibrium point, Ef when R0 1.The analysis also shows that there is a possibility of a forward bifurcation