Partially Oriented 6-star Decomposition of Some Complete Mixed Graphs

Let $M_v$ denotes a complete mixed graph on $v$ vertices, and let $S_6^i$ denotes the partial orientation of the 6-star with twice as many arcs as edges. In this work, we state and prove the necessary and sufficient conditions for the existence of $\lambda$-fold decomposition of a complete mixed graph into $S_6^i$ for $i\in\{1,2,3,4\}$. We used the difference method for our proof in some cases. We also give some general sufficient conditions for the existence of $S_6^i$-decomposition of the complete bipartite mixed graph for $i\in\{1,2,3,4\}$. Finally, this work introduces the decomposition of a complete mixed graph with a hole into mixed stars

On the Beta-Nakagami Distribution

This study is focused on combining Nakagami distribution and beta distribution with a view to obtaining a distribution that is better than each of them individually in terms of the estimate of their characteristics and parsimonious in their parameters using the logit of beta (the link function of the Beta generalized distribution by Jones (2004)). The resulting model, beta Nakagami distribution is better in terms of its flexibility and shape. The statistical properties of the proposed distribution such as moments, moment generating function, the asymptotic behavior among others were investigated. Our findings showed that beta Nakagami apart from being flexible, has better representation of data than Nakagami distribution.  It therefore describes situations better than the Nakagami distribution

Pathophysiological changes that affect drug disposition in protein-energy malnourished children

Protein-energy malnutrition (PEM) is a major public health problem affecting a high proportion of infants and older children world-wide and accounts for a high childhood morbidity and mortality in the developing countries. The epidemiology of PEM has been extensively studied globally and management guidelines formulated by the World Health Organization (WHO). A wide spectrum of infections such as measles, malaria, acute respiratory tract infection, intestinal parasitosis, tuberculosis and HIV/AIDS may complicate PEM with two or more infections co-existing. Thus, numerous drugs may be required to treat the patients. In-spite of abundant literature on the epidemiology and management of PEM, focus on metabolism and therapeutic drug monitoring is lacking. A sound knowledge of pathophysiology of PEM and pharmacology of the drugs frequently used for their treatment is required for safe and rational treatment. In this review, we discuss the pathophysiological changes in children with PEM that may affect the disposition of drugs frequently used for their treatment. This review has established abnormal disposition of drugs in children with PEM that may require dosage modification. However, the relevance of these abnormalities to the clinical management of PEM remains inconclusive. At present, there are no good indications for drug dosage modification in PEM; but for drug safety purposes, further studies are required to accurately determine dosages of drugs frequently used for children with PEM

A Note on “Malaria at Parturition in Nigeria: Current Status and Delivery Outcome”

We read the recent article by (Mokuolu et al. 2009) with keen interest and would like to congratulate them for a job well done. However, we would like to raise a few points relating to the limitations of the study

Analysis of Diabetes Data using Extended Cox Model with Frailty under Partial and Penalized partial likelihood estimation methods

Data on Diabetes were analyzed using partial likelihood (Pl) and penalized partial likelihood (Ppl) estimation methods in non-proportional hazards model with dichotomous time-varying covariates. Gamma and Inverse Gaussian frailty distributions were used to account for patient- specific unobserved heterogeneity. Four likelihood configurations were formed from the combinations of the two estimation methods and frailty distributions. These are Partial likelihood with Gamma frailty, Partial likelihood with Inverse Gaussian frailty, Penalized partial likelihood with Gamma frailty and Penalized partial likelihood with Gamma frailty.  The results revealed that age and body mass index of the patients significantly increased the risk of death from diabetes, while regular exercise had significant decreased risk of death. Penalized partial likelihood estimation method generally outperformed models with Partial likelihood under all scenarios for the data and Gamma frailty provided a better fit in accounting for unobserved heterogeneity among the diabetic patients

Semi-Parametric Non-Proportional Hazard Model With Time Varying Covariate

The application of survival analysis has extended the importance of statistical methods for time to event data that incorporate time dependent covariates. The Cox proportional hazards model is one such method that is widely used. An extension of the Cox model with time-dependent covariates was adopted when proportionality assumption are violated. The purpose of this study is to validate the model assumption when hazard rate varies with time. This approach is applied to model data on duration of infertility subject to time varying covariate. Validity is assessed by a set of simulation experiments and results indicate that a non proportional hazard model performs well in the phase of violated assumptions of the Cox proportional hazards

Quality of Life of Chronic Kidney Disease Patients in a Nigerian Teaching Hospital

Studies assessing the quality of life of chronic kidney disease patients prior to initiating dialysis therapy are much fewer than studies of patients on dialysis. However many of the factors affecting quality of life during dialysis already exist in the early stage of chronic kidney disease and suitable management of these factors could have a positive influence on the course of the illness. This is a cross-sectional study assessing the relationship between sociodemographic and medical factors with the quality of life of chronic kidney disease patients. The study comprises of 113 consecutive adult chronic kidney disease patients attending the renal clinic of the university of Ilorin teaching hospital, Ilorin, Nigeria. Health related quality of life was assessed using the 26 item World Health Organization quality of life instrument (WHOQOL-BREF). Age greater than 60 years (p=0.001), receiving adequate social support (p=0.038) were statistically significantly associated with higher score on Environment domain of WHOQOL-BREF, while being divorced (p=0.005) was significantly related to a lower score (i.e. poorer QOL) on this domain. Among the clinical characteristics, being at an advanced stage of CKD and being on current treatment with RRT were statistically significantly associated with lower scores on overall QOL (p=0.017; p=0.045 respectively). These two clinical characteristics were also associated with lower scores (i.e. poorer QOL) on the physical health (p=0.007; p<0.001 respectively), psychological health domain (p=0.04; p=0.01 respectively) and environment domain (p=0.035; p=0.018 respectively) of the WHOQOL-BREF. Both the presence of complication and using higher number of medications were statistically significantly associated with lower scores on health satisfaction (p=0.026; p=0.01 respectively) and the physical health domain (p=0.006; p<0.001 respectively) of WHOQOL-BREF. Sociodemographic and clinical factors influence the quality of life of chronic kidney disease patients. However, efforts made at early detection and treatment with provision of social assistance may help reduce their negative effects on the quality of life of these patients. Keywords: quality of life; chronic kidney disease; Nigeri

BI-OPTIMIZATION OF DURABILITY AND RHEOLOGICAL PERFORMANCE OF OIL WELL CEMENT SLURRY USING LOCALLY SOURCED EXTENDER

Bentonite used during drilling and cementing operations in Nigeria are imported into the country despite the availability of this raw material, which will increase the Gross Domestic Products (GDP) of this country if properly processed and utilized instead of imported bentonite. This investigation evaluated the performance of three selected Nigerian bentonites sourced from the South-Western part of Nigeria for oil well-cementing operation. The raw and beneficiated samples from each location were prepared and characterized using X-ray Fluorescence (IVT-20 XRF) to determine the elemental composition of each sample pre and post beneficiation. The beneficiated sample with properties close to that of Wyoming bentonite was chosen for the oil well cement slurry analysis. The measured parameters used in the analysis of the suitability of local samples used in oil well-cementing operation were compressive strength and rheological properties. Box-Behnken Design (BBD) was used for the study of the optimum quantity of bentonite required for cementing specification and bi-optimization values for both the comprehensive and rheological properties. The results of this investigation showed that all local clay samples in raw form failed the specification of the American Petroleum Institute (API). After beneficiation, Ibeshe Bentonite (IB) had the highest sodium content and the ratio of the exchangeable cations, 190% increment in sodium-ion was recorded in IB after beneficiation and the slurry yield of IB (2.7 ft3 per sack) was greater than that of  Wyoming Bentonite 1.9 ft3 per sack) when both are subjected to the same experimental condition. Bi-optimization models predicted optimum experimental conditions with an accuracy of between 0.35 and, 1.26 % for both comprehensive and rheological parameter

Electro-Optical Characterization of Stannous Oxide Based Conductive Glass Fabricated Locally with Stannous Chloride Dihydrate Precursor

Most commercially available conductive oxides such as indium doped tin oxide (ITO) and fluorine doped tin oxide (FTO) are expensive. This has made local production of alternative oxides necessary. This work demonstrates local production of transparent conducting stannous oxide (SnO) film via thermal decomposition of stannous chloride dihydrate (SnCl2·2H2O). The films were then characterized optically and electrically using UV/VIS spectrophotometer and four point probe, respectively. The thickness of the film increased linearly with precursor mass. While the sheet resistance and optical transmittance decreased, the optical absorbance increased with increased thickness. Average optical transmittance ranged between 85% and 94% and the sheet resistance lies between 62.89 Ω/sq and 84.57 Ω/sq. With these characteristics, the deposited film will be useful for optoelectronic applications