Comparison Of Survival Models And Estimation Of Their Parameters With Respect To Mortality in a Given Population .

In  this  research, we consider three  different  survival models  under   the assumption  of Gompertz  model as the baseline  distribution. We compare the fitting results of the Exponential distribution , the Gompertz distribution and the Gompertz - Makeham  model in a given  population. As the human lifespan decreases, more and more people are becoming interested in mortality rates at higher ages.   The  aim  of   this  study  is  to   estimate     the  robust  and  reliable    estimates  of  level   and   trend     in   mortality   in  Homa-Bay county , Kenya  .  The purpose of this study is to find out if the population  of  Homa-Bay area in Nyanza Province fits the Gompertz model and also to compare different survival models parametrically   in  a  population. And  also  to  determine the relationship between death  rate  and  age  in the area. . Akaike Information Criterion (AIC) is used to identify the best model. The expected output is that   the preferred model is the one which satisfies the characteristics of the given population. Keywords: Gompertz distribution, Gompertz-Makeham Model , Expected life time, Force of mortality, AIC,  Stochastic process

Prevalence and Patterns of Alcohol and Drug Abuse among University Students

Globally, 29 million people face challenges on psychoactive substance abuse. Three million deaths and 132.6 million disability adjusted life years were attributed to alcohol globally in 2016. Use of psychoactive substances by the youth negatively affect cognitive development, judgement, health and academic outcomes, Kenya has 7.9 million youths aged 15-24 years, among which are University students. Individual characteristics and environmental influences from family and peers makes the youth vulnerable to psychoactive substance use. This study aimed to determine the prevalence of alcohol and substance use; factors associated with alcohol and substance use; and predictive factors for the vice among University students. The study was conducted at three purposively sampled University of Nairobi campuses. A selfadministered questionnaire on psychoactive substance use was used. Respondents were registered students at the time of study residing in the three campuses. Hostels were systematically sampled and rooms randomly selected. Independent variables included commonly used psychoactive substances. Dependent variables were age, gender, campus and year of study. Data was analyzed using Stata SE 12 software. Descriptive,logistic regression and multivariate analysis were conducted. Majority of students were in the 20-24 years age bracket and the highest student proportion (29.3%) in 3rd year of study. The proportion of male respondents was 55.2%. Alcohol, marijuana and cigarettes were the most prevalent substances used at 41%, 14% and 13.5% respectively. Cocaine and heroin were the least used. Consumption of alcohol was significantly associated with male gender, higher year of study, city campuses (Main and Chiromo) and older age. Marijuana use was significantly associated with the male gender, higher year of study and older age. Use of cocaine and heroin were not significantly associated with any of the demographic factors under study. Male gender, city campuses and higher year of study were predictive factors for alcohol consumption and cigarette smoking

Stability of Anthocyanin Sensitized TiO2 Photoelectrochemical (PEC) Solar Cells Prepared by Sol Gel Process

Highly porous dye sensitized TiO2 thin film solar cells have been prepared by the sol gel process. Sensitization was achieved by use of anthocyanin pigment extracted from delphinidin purple and cyanidin 3-5 diglucose (C35D). Sensitization was also studied on ruthenium complex RuL* sensitization dye. Dye sensitized photoelectrodes have exhibited broad transmission minimum in the visible range. Solar cells fabricated from these electrodes gave overall conversion efficiencies of 3.16% for delphinidin purple and 2.97% for C35D. RuL dye sensitized solar cell gave 4.84%. The cells\' stability performance in terms of photovoltage was found to drop with time of exposure. However the cells still exhibited I-V characteristics over a long period (six months) of study. *L = bis (isthiocyanato) ruthenium (II)-bis-2,2-bipyridine-4,4\'-dicarboxylic ligand (Af. J. of Science and Technology: 2002 3(2): 56-61

Re-admission rate and its associated factors in a county hospital in Kenya

Objective: To assess the re-admission rate and its associated factors in the paediatric ward at Thika level five hospital. Design: A descriptive cross-sectional study. Setting: Secondary level hospital in sub-Saharan Africa. Subjects: A total of 803 children aged 13 years and below admitted between March and June 2019. Outcome measures: Re-admission of a patient within 30 days of the index admission. Results: The study found a re-admission of rate 10.2%. Among the readmitted patients 26.83% had a comorbidity and 29.26% had been given incorrect drug dosages during their first admission. A greater proportion (63.4%) of the readmitted patients had the same diagnosis with the index admission with pneumonia, gastroenteritis and meningitis ranking top in the list. A larger percentage of the readmitted children were discharged (83.5%), 8.9% were referred and 7.6% died. Multivariate analysis identified strong associations of hospital re-admission with the length of hospital stay during the index admission, the qualification of the health practitioner who initially discharged the patient and whether the correct drug dosages were administered during the index hospital stay. Conclusion: About a tenth of discharged children were readmitted within 30 days of discharge. Pneumonia was the commonest condition at admission and re-admission. The hospital factors associated with re-admission included length of hospital stay, level of training of the health care worker who discharged the patient as well as having received incorrect drug dosage during the first admission. There were no significant patient factors

Thermal Shock Resistance of a Kyanite-Based (Aluminosilicate) Ceramic

This paper presents the results of a combined experimental and theoretical study of microstructure and thermal shock resistance of an aluminosilicate ceramic. Shock-induced crack growth is studied in sintered structures produced from powders with different particle size ranges. The underlying crack/microstructure interactions and toughening mechanisms are elucidated via scanning electron microscopy (SEM). The resulting crack-tip shielding levels (due to viscoelastic crack bridging) are estimated using fracture mechanics concepts. The implications of the work are discussed for the design of high refractory ceramics against thermal shock

Structural and Optical Characterization of Nitrogen-doped TiO 2 Thin Films Deposited by Spray Pyrolysis on Fluorine Doped Tin Oxide (FTO) Coated Glass Slides

Abstract Undoped and nitrogen-doped titanium dioxide (TiO2) thin films of 400 nm thick deposited by spray pyrolysis were structurally and optically characterized. The effect of substrate temperature on the optical properties of the films was also investigated. Structural studies of the films were undertaken by X-ray diffraction (XRD). Energy dispersive X-ray (EDX) spectrum analysis was used to confirm the presence of nitrogen atoms in the film after doping. The optical properties such as refractive index (n), energy band gap (Eg) and Urbach energy (Eu) were determined from spectrophotometric measurements of reflectance and transmittance for both undoped and doped films. The Undoped films had an energy band gap of 3.25 eV while the doped films had band gap of 2.90 eV. The Urbach energy increased from 1.00 eV for undoped films to 1.04 eV for the nitrogen-doped films. The reduction in energy band gap and increase in Urbach energy was attributed to the introduction of nitrogen impurity tail states on either the conduction band or the valence band of the titanium dioxide