Faculty of Science Engineering and Technology
http://repository.chuka.ac.ke/handle/chuka/426
2022-04-14T06:23:57ZModeling and Forecasting Kenyan GDP Using Autoregressive Integrated Moving Average (ARIMA) Models
http://repository.chuka.ac.ke/handle/chuka/15934
Modeling and Forecasting Kenyan GDP Using Autoregressive Integrated Moving Average (ARIMA) Models
Musundi, Sammy Wabomba; M’mukiira, Peter Mutwiri; Mungai, Fredrick
The Gross Domestic Product (GDP) is the market value of all goods and services produced within the borders of a
nation in a year. In this paper, Kenya’s annual GDP data obtained from the Kenya National Bureau of statistics for the years 1960
to 2012 was studied. Gretl and SPSS 21 statistical softwares were used to build a class of ARIMA (autoregressive integrated
moving average) models following the Box-Jenkins method to model the GDP. ARIMA (2, 2, 2) time series model was
established as the best for modeling the Kenyan GDP according to the recognition rules and stationary test of time series under
the AIC criterion. The results of an in-sample forecast showed that the relative and predicted values were within the range of 5%,
and the forecasting effect of this model was relatively adequate and efficient in modeling the annual returns of the Kenyan GDP.
Finally, we used the fitted ARIMA model to forecast the GDP of Kenya for the next five years.
2016-04-13T00:00:00ZMedicinal Plants Used for Treatment of Gastrointestinal Infections in Tharaka-Nithi County
http://repository.chuka.ac.ke/handle/chuka/15756
Medicinal Plants Used for Treatment of Gastrointestinal Infections in Tharaka-Nithi County
Kiteme M., Purity; Onyango O., Benson; Njagi C., Eric; Ogolla O., Fredrick
Health care is a basic need to humans which can only be achieved with medicines with high
efficacy against disease causing pathogens. Globally, gastrointestinal infections are major health
concern particularly to travelers since over 60% visiting tropical and subtropical regions develop
diarrhea. Herbal plants have been used for decades to treat gastrointestinal infections globally
including Tharaka-Nithi County in Kenya. However, there is little information on the demography of
herbalist and the plants used in treatment of gastrointestinal infections such as typhoid, cholera
and shigellosis. A cross sectional survey was carried out involving thirty herbalists to assess their
demographic data and to establish herbs commonly used to treat typhoid, cholera and shigellosis
in Tharaka-Nithi County. Data collected was subjected to Chi square test of association and
descriptive statistics and presented in percentages. There were more male herbalists (65.52%) in
the study than female herbalist (34.48%). Most of the herbalist (65.52%) were aged above 70
years. There was a significant (p < 0.05) association between herbalists’ level of education and
age (X
2
(6, N = 30) = 17.349, p = 0.008). Most herbalists were found to have below primary
education level 58.62%. Aloe vera, Aspilia pluriseta, Ficus sycomorus and Physalis peruviana were
identified as commonly used plants for treatment of cholera with Aspilia pluriseta being most
preferred (27%) by herbalist above the age of 70 years. Vangueria infausta, Eucalyptus globulus, Carissa edulis and Erythrina abysinnica were commonly used for treatment of shigellosis with
Eucalyptus globulus being most preferred (58.6%) by herbalist above the age of 70 years.
Erythrina abysinnica, Carissa edulis, Vangueria infausta and Eucalyptus globulus were commonly
used for treatment of typhoid while 50.0% of herbalist above the age of 70 preferred Erythrina
abysinnica. Most of the herbalists had below primary education level. In conclusion, herbal
medicine is mostly dispensed by older people in Tharaka-Nithi County in Kenya. Different herbal
plants are used in the treatment of cholera, shigellosis and typhoid.
2022-08-22T00:00:00ZScreening of Antimicrobial Activity of Poly Herbal Extracts against Bacterial Pathogens Causing Gastroenteritis in Tharaka Nithi County, Kenya
http://repository.chuka.ac.ke/handle/chuka/15755
Screening of Antimicrobial Activity of Poly Herbal Extracts against Bacterial Pathogens Causing Gastroenteritis in Tharaka Nithi County, Kenya
Mbithe P. Kiteme; Benson O. Onyango; Eric C. Njagi; Fredrick O. Ogolla
Herbals have been used for decades to treat gastrointestinal infections across the world, including
in Tharaka-Nithi County, Kenya. Crude extracts from herbs have long been prescribed by traditional
healers for treatment of typhoid, cholera, and shigellosis. However, the effectiveness of extracts
obtained using different extraction solvents such as methanol, acetone, and hexane have not fully
been evaluated. This study aimed at evaluating the effect of solvents (Ethanol, hexane, and
methanol) on the yield of crude extract from plants (Erythrinna abyssinica, Aspilia pluriseta,
Vangueria infausta, Ficus sycomorus, and Carissa edulis), assessing the effect of the solvents on
extracted active metabolites, and determining the effect of these solvents on extract’s bioactivity against Vibrio cholerae, Shigella flexneri, and Salmonella typhimuriumi and, Escherichia coli that
served as a model organism for screening plant extracts against Gram-negative bacteria. Crude
extracts were obtained by soaking dried ground plant parts in individual solvents, which were then
concentrated by a rotary evaporator. The phytochemical screening to detect plant metabolites was
done qualitatively. Bioassays to analyze the efficacy of the plant crude extracts against the
microbes were carried out in 4×3×3×5 factorial experiment laid out in a completely randomized
design. The determination of bioactivity of herbal extracts was carried out using minimal inhibition
concentration and minimum bactericidal concentration methods. Data obtained on the bioactivity
assay (Count of the bacteria colony forming units) was analyzed using the Kruskal-Wallis test at α =
0.05, and medians were compared by the Wilcoxon rank sum test in Scientific Analysis System
version 9.4. Methanol solvent produced higher quantities of crude extracts for all the herbal
samples used with, Vangueria infausta producing the highest extract (5.06g). Most phytochemicals
were present in Methanolic extracts compared to hexane and acetone extracts. There was a
significant (p < 0.05) difference in the bioactivity of different herbal plants against bacterial
pathogens at different concentrations of crude extract. The efficacy of plant extract increased
progressively from 100ppm to 1000ppm concentration. Methanol is recommended for use in the
extraction of medicinal plant extracts as it leads to improved potency as compared to hexane and
acetone.
2023-04-27T00:00:00ZEffect of pH, Carbon and Nitrogen Sources on Antibiotic Production by Actinomycetes Isolates from River Tana and Lake Elementaita, Kenya
http://repository.chuka.ac.ke/handle/chuka/15753
Effect of pH, Carbon and Nitrogen Sources on Antibiotic Production by Actinomycetes Isolates from River Tana and Lake Elementaita, Kenya
O. Shikuku, Bonface; Kiruki, Silas; Kuria, Eric; Mayo, Domnic; O. Ogolla, Fredrick
The escalating concern over antibiotic resistance and its profound impact on public health have
underscored the urgent need to explore alternative reservoirs of antimicrobial agents. In this regard,
Actinomycetes have emerged as a compelling area of investigation due to their remarkable capacity
to produce bioactive compounds. Therefore, this study sought to investigate the influence of pH and
various carbon and nitrogen sources on the antibacterial activity of Actinomycetes isolates collected
from Lake Elementaita and River Tana. By examining the effects of these factors, we aimed to gain
insights into the optimization of growth conditions and nutrient availability to enhance the production
of bioactive compounds with potent antibacterial properties. The Actinomycetes isolates used in this study were from Lake Elementaita and River Tana, known for their diverse ecological characteristics
and potential as sources of bioactive compounds. The isolates were subjected to morphological,
biochemical, and molecular techniques to ensure accurate identification. To assess the antibacterial
activity of the Actinomycetes isolates, they were tested against E. coli using the agar well diffusion
method. The independent variables examined in this study were pH levels (4, 7, and 9) as well as
different carbon sources (fructose and sucrose) and nitrogen sources (urea and sodium nitrate). The
diameter of the inhibition zones served as the dependent variable. The data collected on the effects
of pH and nutrients on the inhibition zones of Actinomycetes isolates were subjected to statistical
analysis. One-way ANOVA was performed to assess significant differences in antibacterial activity
among the isolates under different carbon and nitrogen preference. Mean values were compared
using the LSD test at a significance level (α) of 0.05. Furthermore, the Kruskal-Wallis test was
utilized to analyze the pH preferences of the Actinomycetes isolates at a significance level (α) of
0.05. The results showed that pH significantly influenced the bioactivity of the Actinomycetes
isolates, with pH 7 exhibiting the highest inhibition zones against E. coli. The isolates displayed
varied antibacterial activities depending on the carbon and nitrogen sources provided. Sucrose was
the most preferred carbon source, followed by fructose, while urea was the preferred nitrogen
source, followed by sodium nitrate. The study concluded that pH and nutrient availability play crucial
roles in determining the antibacterial activity of Actinomycetes isolates. Other than contributing to
our in-depth understanding of the factors influencing the antimicrobial potential of Actinomycetes,
the results of this study highlight the importance of optimizing growth conditions and nutrient
availability to enhance the production of bioactive compounds with potent antibacterial
properties. Further investigations and exploration of Actinomycetes from diverse
environments are recommended to discover new bioactive molecules for combating antibiotic
resistance.
2023-08-04T00:00:00Z