Journal of Plant breeding and Crop Science, Mar 31, 2011
Cassava is an important food security crop in semi-arid, Eastern Kenya, but production is constra... more Cassava is an important food security crop in semi-arid, Eastern Kenya, but production is constrained by planting late bulking landraces. Therefore, farmer participatory variety selection was initiated with the aim of identifying early bulking varieties with preferred root qualities. Four popular local varieties were crossed with six early-bulking varieties selected from IITA germplasm in a North Carolina II mating scheme. The resultant 225 cloned F 1 progenies were evaluated for early bulking in a 15 x 15 simple lattice design with two replications at KARI-Kiboko farm in Eastern Kenya. Sixty-five farmers participated in the selection of early bulking genotypes with preferred root qualities during the second and third harvests at 7 and 8 months after planting. At 7 months, there was a significant variation among genotypes for root bulking, cyanide content, dry matter content, harvest index and root number. Farmers subjected all the genotypes to a preference test and selected 30 genotypes (13%), which combined early-bulking and high root quality. A selection index based on farmers' ranking of agronomic traits was then imposed on the selected 30 genotypes to identify those that were superior in both agronomic and end-user traits for possible release and advancement. The selected genotypes were all significantly superior to the parents. The top 10 genotypes displayed above average performance for all agronomic traits. Involving farmers in selection helped to identify early bulking genotypes with end-user root qualities that could/should ultimately accelerate their adoption.
Introduction: Despite the growing popularity of organizational learning (OL) and its constructs, ... more Introduction: Despite the growing popularity of organizational learning (OL) and its constructs, the concept remains complex and vague for researchers as well as managers. Mental models are inherently difficult to study and several methods have been developed that essentially document a mental model in the form of a mind map or concept diagram. Ob jective: This study aimed to determine the impact of mental models as a construct of organizational learning on competitive advantage in Kenya’s Oil Marketing Sector. The latent aspects of competitive advantage; organization agility, innovation, barriers to entry, mass customization and inimitability (difficulty to duplicate) were investigated against the independent variable. Methodology: The research design was explanatory, non-contrived and cross-sectional study on Kenya’s oil marketing sector. A sample size of 425 was drawn from oil marketing companies that had a market share above 1% according to the Petroleum Institute of East Africa...
Introduction: Systems thinking has emerged as the convergence point between sciences, a fundament... more Introduction: Systems thinking has emerged as the convergence point between sciences, a fundamental way of interpreting nature and mastering the ever increasing complexity of the products of human intelligence. Ob jective: This study aimed to determine the impact of systems thinking as a construct of organizational learning on competitive advantage in Kenya’s Oil Marketing Sector. The latent aspects of competitive advantage; organization agility, innovation, barriers to entry, mass customization and inimitability (difficulty to duplicate) were investigated against the independent variable. Methodology: The research design was explanatory, non-contrived and cross-sectional study on Kenya’s oil marketing sector. A sample size of 425 was drawn from oil marketing companies that had a market share above 1% according to the Petroleum Institute of East Africa. Structured questionnaires were used as the data collection tool. Correlation, regression and SEM model were used to analyze the stu...
Kindness, and Tammy Bush. 2011. PCA modeling of eucalyptus forest soil geochemical parameters, la... more Kindness, and Tammy Bush. 2011. PCA modeling of eucalyptus forest soil geochemical parameters, labile metals and tree species variability. Journal of Wood Chemistry and Technology (Submitted). Contributions: I performed the research, data analysis and write-up; all my Supervisors provided guidance and ideas as well as editing the manuscript.
Western Indian Ocean journal of marine science, 2021
A complex mix of natural processes exist in nearshore and offshore waters which influence coastal... more A complex mix of natural processes exist in nearshore and offshore waters which influence coastal and marine ecosystem productivity. An understanding of the biogeochemical processes involved is a key element in interdisciplinary studies of primary production, oceanic flux and storage of carbon dioxide. Water circulation in the East African region is influenced by coastal currents driven by monsoon winds. There are four oceanic currents influencing Kenya’s coastal waters; namely the East African Coastal Current, the Somali Current, the Southern Equatorial Current and the Equatorial Counter Current. The Kenyan fishing industry is slowly embracing offshore fishing grounds, and the North Kenya Bank is emerging as the next fishery frontier. This study aims to provide insight on the processes driving the productivity of Kenya’s territorial waters. The variable Si* (the difference between available silicate [Si(OH)4] and nitrate [NO3-]) was employed as a proxy of upwelling. It was highly p...
Western Indian Ocean journal of marine science, 2021
A socio-economic assessment was carried out at Amu and Shela in Lamu County and Ngomeni in Kilifi... more A socio-economic assessment was carried out at Amu and Shela in Lamu County and Ngomeni in Kilifi County on the coast of Kenya. The aim was to establish fisher perspectives on the livelihood impacts of changes in upwelling associated with the East African Coastal Current, and adaptations in fishing practices to determine the vulnerability, resilience and adaptation options for fisheries dependent communities in this upwelling region. Primary data and information were collected through direct observation, semi-structured interviews, key informant interviews and oral histories. Descriptive and non-parametric analysis was conducted for quantitative data and content analysis for qualitative data. The study covered 92 respondents out of which 90 were male. About 82.5 percent of the respondents had attained different levels of primary school education and below, and were therefore highly vulnerable to climate change impacts. Furthermore, 80.4 percent of the respondents were aged between 2...
The North Kenya Banks have long been considered an important emerging fishery with the potential ... more The North Kenya Banks have long been considered an important emerging fishery with the potential to spur economic growth for local fishing communities. As a regionally important extension to the otherwise narrow East African continental shelf, the North Kenya Banks remain under studied with implications for efforts to develop a sustainable fisheries management strategy. The local marine ecosystem is known to be strongly influenced by wind driven upwelling processes with seasonal variability driven by the changing monsoon seasons being of particular importance. Nevertheless, the Western Indian Ocean is warming due to anthropogenic climate change with evidence indicating reduced ocean productivity in future. How the ecosystem of the North Kenya Banks will respond is currently uncertain but is of great importance due to the significance of coastal fishery resources to coastal communities, and growing Blue Economy initiatives to exploit the North Kenya Banks fisheries more widely. There is, however, limited knowledge of the processes influencing productivity over the North Kenya Banks regions and currently there is no management plan in place to sustainably manage the fishery resources. Here, information about the North Kenya Banks fisheries are examined in relation to environmental processes and threats from climate change impacts with suggestions for future research and management directions.
The Tana River is the longest river system in Kenya (~1000 km) and contributes ~ 50% of the total... more The Tana River is the longest river system in Kenya (~1000 km) and contributes ~ 50% of the total river discharge to Kenyan coastal waters. The river discharges significant amounts of nutrients and sediments, reaching ~24,000 tons per day during the rainy season (March-April), into Ungwana Bay (North Kenya Banks). The bay is an important habitat for high-value Panaeid prawn species which sustain important small-scale fisheries, semi-industrial bottom trawl prawn fisheries, and is the livelihood mainstay in the surrounding counties. In this study we analysed >20 years of satellite-derived chlorophyll-a observations (Chl-a, an index of phytoplankton biomass), along with in situ river discharge and rainfall data, to investigate if the Tana River discharge is a major driver of local phytoplankton biomass in Ungwana Bay and for the neighbouring Kenyan shelf. We find that during the rainy inter-monsoon (March-April), a significant positive relationship (r = 0.63, p < 0.0001) exists between river discharge and phytoplankton biomass. There is a clear time-lag between rainfall, river discharge (1-month lag) and local chlorophyll biomass (2-months lag after discharge). Unlike offshore waters which exhibit biannual chl-a peaks (0.22 mg m − 3 in February, and 0.223 mg m − 3 in August/September), Ungwana Bay displays a single peak per annum in July (2.51 mg m − 3), with indications that river discharge sustains phytoplankton biomass for several months. Satellite-derived observations and Lagrangian tracking simulations indicate that higher Chl-a concentrations remain locally within the bay, rather than influencing the broader open waters of the North Kenya Banks that are mainly impacted by the wider oceanic circulation.
International Journal of Research and Engineering, 2018
The cost, availability and stability of power are parameters that greatly define the quality of e... more The cost, availability and stability of power are parameters that greatly define the quality of energy supplied by a generating system. A hybrid power system with different sources of energy must be properly designed in order to capitalize on the positive features of the deployed resources. Hybrid power system optimization is a process that allows for deliberate attainment of desired output from a power system. In this paper, a learning institution, East African School of Aviation (EASA) was selected as a case study for investigating the outcome of harnessing local energy resources to serve a commercial consumer in Kenya. A cost competitive hybrid power system was obtained through Simulation and optimization processes.
Cardio-metabolic disease is a leading cause of death worldwide, with extremely high prevalence in... more Cardio-metabolic disease is a leading cause of death worldwide, with extremely high prevalence in western, industrialized societies relative to developing nations and subsistence-level populations. The high prevalence in western societies has been attributed to dietary and lifestyle changes associated with industrialization, but current work has relied on health comparisons between separate, genetically distinct populations to draw these conclusions. To more robustly determine how lifestyle affects cardio-metabolic health, we collected interview and biomarker data from a single population undergoing a rapid lifestyle transition. We sampled individuals of the Turkana tribe who practice subsistence-level, nomadic pastoralism (the traditional, ancestral way of life for this group) versus individuals who no longer practice pastoralism and engage either minimally or strongly with the market economy. Comparisons across this lifestyle gradient revealed clear, non-linear effects of industri...
Cassava bacterial blight (CBB), caused by Xanthomonas axonopodis pv. manihotis (Xam), is the most... more Cassava bacterial blight (CBB), caused by Xanthomonas axonopodis pv. manihotis (Xam), is the most important bacterial disease of cassava. There is no information available on the morphological and genetic variability of Xam isolates from Kenya. The aim of this study therefore, was to determine the diversity of Xam isolates from different cassava growing regions of Kenya using phenotypic characteristics and repetitive DNA polymerase chain reaction-based fingerprinting (rep-PCR). Thirty three isolates were recovered from infected cassava leaf samples collected from farmers' fields in cassava growing regions. The dendrogram generated from analysis of phenotypic characteristics of the isolates produced two major clusters at 75% similarity level. Analysis of 19 isolates with repetitive extragenic palindromic (rep) primers yielded characteristic fingerprint pattern with bands ranging between 400 and 2000 bp in size and their numbers ranged from 1 to 6 bands per isolate. Cluster analysis using unweighted pair group method with arithmetic averages (UPGMA) did not reveal any significant differences in clustering and relationship to the geographical origin, with exception of a single isolate that had unique fingerprints. These findings indicate that Xam population in Kenya evolved from the same origin and is a uniform population, and this may prove useful in future breeding programmes.
Inflammation causes discomfort, suffering and lower productivity of the victims. Synthetic anti-i... more Inflammation causes discomfort, suffering and lower productivity of the victims. Synthetic anti-inflammatory drugs are not readily available and have adverse side effects. Alternative herbal medicines possess bioactive compounds that are safer and efficient in the management of various diseases and disorders. The present study evaluated for the anti-inflammatory activity of methanolic extracts of Kigelia africana and Acacia hockii in mice to scientifically validate their traditional use among the Embu and Mbeere communities in Kenya. The plant samples were collected with the help of local herbalists in Embu County, Kenya and transported to Kenyatta University biochemistry and biotechnology laboratories for cleaning, air drying, milling, and extraction. Swiss albino mice of either sex were randomly divided into six groups of 5 animals each; normal control, negative control, positive control and three experimental groups. The anti-inflammatory activity was tested using carrageenan-induced hind paw edema method. The anti-inflammatory activity of the extracts was compared to reference drug diclofenac. The leaf extract of K. africana reduced inflamed hind paw diameter of mice by between 0.21%-4.98% while the stem bark extract of A. hockii reduced inflamed hind paw diameter by between 0.6%-5.38%. The diclofenac reduced inflamed hind paw diameter by between 1.11%-4.9%. The qualitative phytochemical screening indicated the presence of saponins, flavonoid, alkaloids, terpenoids, phenolics, and cardiac glycosides. The present study demonstrated potent antiinflammatory activities of methanolic extracts of K. africana and A. hockii in a dose-dependent manner, which supports their traditional use. The present study, therefore, recommends the ethnomedicinal use of K. africana and A. hockii in the management of inflammation.
Due to emergence of microcontrollers which enable real-time logging, viewing and analysis of data... more Due to emergence of microcontrollers which enable real-time logging, viewing and analysis of data, many new generation data acquisition products have been developed. There is an increasing demand for an improved, efficient and up-to-date microcontroller-based data logger.In this study, a microcontroller-based data logger was developed to measure the wind speed and direction using anemometer and wind vane sensors respectively. The collected data was transmitted to a Personal Computer (PC) through an RS-232 serial interface, which was processed using the 208W Data logger support software and stored in EEPROM memory for post process analysis. In order to test the effectiveness of the logger, wind data measured by the microcontrollerbased data logging system were analyzed through plotted line graphs, simple linear regression charts and wind rose diagrams.The correlation indices for the two three sets of wind speed data in the morning, midday and evenings were 0.997, 0.997 and 0.999 respectively. The wind speed measured by the calibrated sensor correlated well with JKUAT Meteorological data. The strong correlation indicated that developed system was effective and appropriate for measuring wind speed and direction. The system being automated, accurate, appropriate and at the same time cost effective, has potential use in weather forecasting, wind power plants, chemical manufacturing process and in airports among other applications. Further studies can be done to find the relationship between the wind speed and the frequency response of the encoder by use of a wind tunnel.
International Journal of Healthcare Management, 2013
Entrepreneurship studies are highly necessary in the healthcare field, as nowadays, managers perf... more Entrepreneurship studies are highly necessary in the healthcare field, as nowadays, managers perform entrepreneurial activities to generate innovative strategies in order to obtain a competitive advantage in the turbulent healthcare environment. Despite this industry faces complexity and growing competition, healthcare providers have been rarely analysed from the entrepreneurial point of view. As very little is known about this topic, we use a multiple-case studies approach to inductively develop propositions. This study applies the construct of entrepreneurial orientation (EO) in the context of private healthcare organizations. This research serves as an initial attempt to account for the determinants of some dimensions of EO in healthcare organizations, in order to comprehend how innovativeness, risk-taking, and proactiveness performs. We also consider the effect of family involvement and of the professionalization phenomenon in secondor subsequentgeneration firms on the EO of family-owned healthcare organizations.
American Journal of Physics and Applications, 2015
Wind turbine rotors capture energy from moving wind, their capacity to perform this function depe... more Wind turbine rotors capture energy from moving wind, their capacity to perform this function depends on the coefficient of power (Cp) of the rotor. Through proper aerodynamic design, a rotor's performance can be optimized to take advantage of the smallest available wind speed at any time to produce energy. In this research a computational fluid dynamics simulation was performed to model the best optimum dimensions of an inversely tapered rotor blade using Clark Y airfoil type rotor of 0.6 m diameter. The optimal design values obtained include; tip speed ratio (TSR) of 2.5, lift coefficient to drag coefficient ratio of 1.1 and pitch angle of 8 degrees Using blade element momentum (BEM), the wing profile of each section of the blade was calculated and designed. The unique inverse tapering was done to achieve a better efficiency at the low wind speed range. This was used to fabricate a three blade rotor using carbon composites which was tested in the wind tunnel for Cp. Results showed very good performance of the inverse tapered type as compared with the tapered rotors. The maximum coefficient of power for the inversely tapered was found to be 0.313 at 8 m/s. Visualization test and particle image velocimetry (P.I.V). analysis showed that the inversely tapered rotor is more effective in converting wind power into shaft power than the tapered.
Cassava is ideal for biofortification due to its popularity as a root staple among populations wi... more Cassava is ideal for biofortification due to its popularity as a root staple among populations with high vitamin A malnutrition. The crop is vegetatively propagated and retains the enhanced trait across generations. The combining ability for beta-carotene content and important yield trait was evaluated in a cassava F1 generation. Ten high beta-carotene clones from International Institute of Tropical Agriculture (IITA) were hybridized with ten local clones in a North Carolina Design II mating design. The F1 population was evaluated at the Kenya Agricultural Research Institute (KARI). A total of 125 families were evaluated, including 35 reciprocal crosses. The IITA parents had highly significant (P ≤ 0.001) General Combining Ability (GCA) for pulp colour and plant height. The GCA of the local parents was significant (P≤ 0.05) for harvest index, number of lobes (P≤ 0.05) and for plant height (P≤ 0.001). The Specific Combining Ability (SCA) was significant for harvest index and plant he...
Most of the wind analysis studies have been conducted under steady wind conditions. The study of ... more Most of the wind analysis studies have been conducted under steady wind conditions. The study of real unsteady wind environment, however, is still an open-ended research question. This is attributable to the existing aerodynamic complexities under such conditions. In this paper, therefore, a numerical approach to investigate wind energy potential under unsteady conditions was proposed. In carrying out the study, the wind characteristics for two rural-urban towns in Kenya, namely Marsabit (2 19 0 N, 37 58 0 E) and Garissa (0 28 0 S,39 38 0 E), were selected. A CFD analysis method was used to evaluate both unsteady wind inflow performance and the flow physics that affects the performance on a Vertical Axis Wind Turbine (VAWT). Using the validated CFD model, unsteady wind simulations were performed and the results obtained compared with empirical methods. Compared to the prevailing methods, the proposed numerical approach is not only computationally inexpensive, but also robust in both steady and unsteady wind conditions. The numerical method demonstrates that Garissa station is unsuitable for gridconnected power generation, while Marsabit station is suitable for both grid-connected and standalone power generation activities. The study results will hopefully be of importance to the wind industries that require designs for wind turbines reflecting real unsteady wind environment.
Theileria parasites cause a benign infection of cattle in parts of Australia where they are endem... more Theileria parasites cause a benign infection of cattle in parts of Australia where they are endemic, but have, in recent years, been suspected of being responsible for a number of outbreaks of disease in cattle near the coast of New South Wales. The objective of this study was to identify and characterize the species of Theileria in cattle on six farms in New South Wales where disease outbreaks have occurred, and compare with Theileria from three disease-free farms in Queensland that is endemic for Theileria. Special reference was made to sub-typing of T. orientalis by type-specific PCR and sequencing of the small subunit (SSU) rRNA gene, and sequence analysis of the gene encoding a polymorphic merozoite/piroplasm surface protein (MPSP) that may be under immune selection. Nucleotide sequencing of SSU rRNA and MPSP genes revealed the presence of four Theileria genotypes: T. orientalis (buffeli), T. orientalis (ikeda), T. orientalis (chitose) and T. orientalis type 4 (MPSP) or type C (SSU rRNA). The majority of animals showed mixed infections while a few showed single infection. When MPSP nucleotide sequences were translated into amino acids, base transition did not change amino acid composition of the protein product, suggesting possible silent polymorphism. The occurrence of ikeda and type 4 (type C) previously not reported to occur and silent mutation is thought to have enhanced parasite evasion of the host immune response causing the outbreak.
15th International Workshop on Research and Education in Mechatronics (REM), 2014
This paper investigates a feasibility measurement study for wind resource and a numerical simulat... more This paper investigates a feasibility measurement study for wind resource and a numerical simulation for wind regimes of Marsabit and Garissa stations, both rural-urban towns in Eastern region of Kenya. The experimental wind speed measurement was done using optical anemometer sensors while the wind direction was detected by wind vane sensors. The data logging instrumentation with calibrated wind sensors recorded higher resolution wind data. Based on the wind regimes at the sites, an analysis of aerodynamic performance and flow physics of two-dimensional numerical simulations on a NACA0015 airfoil was done using CFD FLUENT software. The Meteorological wind speed measurement correlated with the calibrated cup anemometer sensors measurement with a correlation coefficient of 0.98. The strong correlation confirms that the experimental anemometer gave the correct readings and practical readings can be approximated to the data from the meteorological station. The wind regimes showed attached flow acceleration over the airfoil surface for various angles of attack. The results provide a reference to the research and development of vertical axis wind turbine for target markets.
Journal of Plant breeding and Crop Science, Mar 31, 2011
Cassava is an important food security crop in semi-arid, Eastern Kenya, but production is constra... more Cassava is an important food security crop in semi-arid, Eastern Kenya, but production is constrained by planting late bulking landraces. Therefore, farmer participatory variety selection was initiated with the aim of identifying early bulking varieties with preferred root qualities. Four popular local varieties were crossed with six early-bulking varieties selected from IITA germplasm in a North Carolina II mating scheme. The resultant 225 cloned F 1 progenies were evaluated for early bulking in a 15 x 15 simple lattice design with two replications at KARI-Kiboko farm in Eastern Kenya. Sixty-five farmers participated in the selection of early bulking genotypes with preferred root qualities during the second and third harvests at 7 and 8 months after planting. At 7 months, there was a significant variation among genotypes for root bulking, cyanide content, dry matter content, harvest index and root number. Farmers subjected all the genotypes to a preference test and selected 30 genotypes (13%), which combined early-bulking and high root quality. A selection index based on farmers' ranking of agronomic traits was then imposed on the selected 30 genotypes to identify those that were superior in both agronomic and end-user traits for possible release and advancement. The selected genotypes were all significantly superior to the parents. The top 10 genotypes displayed above average performance for all agronomic traits. Involving farmers in selection helped to identify early bulking genotypes with end-user root qualities that could/should ultimately accelerate their adoption.
Introduction: Despite the growing popularity of organizational learning (OL) and its constructs, ... more Introduction: Despite the growing popularity of organizational learning (OL) and its constructs, the concept remains complex and vague for researchers as well as managers. Mental models are inherently difficult to study and several methods have been developed that essentially document a mental model in the form of a mind map or concept diagram. Ob jective: This study aimed to determine the impact of mental models as a construct of organizational learning on competitive advantage in Kenya’s Oil Marketing Sector. The latent aspects of competitive advantage; organization agility, innovation, barriers to entry, mass customization and inimitability (difficulty to duplicate) were investigated against the independent variable. Methodology: The research design was explanatory, non-contrived and cross-sectional study on Kenya’s oil marketing sector. A sample size of 425 was drawn from oil marketing companies that had a market share above 1% according to the Petroleum Institute of East Africa...
Introduction: Systems thinking has emerged as the convergence point between sciences, a fundament... more Introduction: Systems thinking has emerged as the convergence point between sciences, a fundamental way of interpreting nature and mastering the ever increasing complexity of the products of human intelligence. Ob jective: This study aimed to determine the impact of systems thinking as a construct of organizational learning on competitive advantage in Kenya’s Oil Marketing Sector. The latent aspects of competitive advantage; organization agility, innovation, barriers to entry, mass customization and inimitability (difficulty to duplicate) were investigated against the independent variable. Methodology: The research design was explanatory, non-contrived and cross-sectional study on Kenya’s oil marketing sector. A sample size of 425 was drawn from oil marketing companies that had a market share above 1% according to the Petroleum Institute of East Africa. Structured questionnaires were used as the data collection tool. Correlation, regression and SEM model were used to analyze the stu...
Kindness, and Tammy Bush. 2011. PCA modeling of eucalyptus forest soil geochemical parameters, la... more Kindness, and Tammy Bush. 2011. PCA modeling of eucalyptus forest soil geochemical parameters, labile metals and tree species variability. Journal of Wood Chemistry and Technology (Submitted). Contributions: I performed the research, data analysis and write-up; all my Supervisors provided guidance and ideas as well as editing the manuscript.
Western Indian Ocean journal of marine science, 2021
A complex mix of natural processes exist in nearshore and offshore waters which influence coastal... more A complex mix of natural processes exist in nearshore and offshore waters which influence coastal and marine ecosystem productivity. An understanding of the biogeochemical processes involved is a key element in interdisciplinary studies of primary production, oceanic flux and storage of carbon dioxide. Water circulation in the East African region is influenced by coastal currents driven by monsoon winds. There are four oceanic currents influencing Kenya’s coastal waters; namely the East African Coastal Current, the Somali Current, the Southern Equatorial Current and the Equatorial Counter Current. The Kenyan fishing industry is slowly embracing offshore fishing grounds, and the North Kenya Bank is emerging as the next fishery frontier. This study aims to provide insight on the processes driving the productivity of Kenya’s territorial waters. The variable Si* (the difference between available silicate [Si(OH)4] and nitrate [NO3-]) was employed as a proxy of upwelling. It was highly p...
Western Indian Ocean journal of marine science, 2021
A socio-economic assessment was carried out at Amu and Shela in Lamu County and Ngomeni in Kilifi... more A socio-economic assessment was carried out at Amu and Shela in Lamu County and Ngomeni in Kilifi County on the coast of Kenya. The aim was to establish fisher perspectives on the livelihood impacts of changes in upwelling associated with the East African Coastal Current, and adaptations in fishing practices to determine the vulnerability, resilience and adaptation options for fisheries dependent communities in this upwelling region. Primary data and information were collected through direct observation, semi-structured interviews, key informant interviews and oral histories. Descriptive and non-parametric analysis was conducted for quantitative data and content analysis for qualitative data. The study covered 92 respondents out of which 90 were male. About 82.5 percent of the respondents had attained different levels of primary school education and below, and were therefore highly vulnerable to climate change impacts. Furthermore, 80.4 percent of the respondents were aged between 2...
The North Kenya Banks have long been considered an important emerging fishery with the potential ... more The North Kenya Banks have long been considered an important emerging fishery with the potential to spur economic growth for local fishing communities. As a regionally important extension to the otherwise narrow East African continental shelf, the North Kenya Banks remain under studied with implications for efforts to develop a sustainable fisheries management strategy. The local marine ecosystem is known to be strongly influenced by wind driven upwelling processes with seasonal variability driven by the changing monsoon seasons being of particular importance. Nevertheless, the Western Indian Ocean is warming due to anthropogenic climate change with evidence indicating reduced ocean productivity in future. How the ecosystem of the North Kenya Banks will respond is currently uncertain but is of great importance due to the significance of coastal fishery resources to coastal communities, and growing Blue Economy initiatives to exploit the North Kenya Banks fisheries more widely. There is, however, limited knowledge of the processes influencing productivity over the North Kenya Banks regions and currently there is no management plan in place to sustainably manage the fishery resources. Here, information about the North Kenya Banks fisheries are examined in relation to environmental processes and threats from climate change impacts with suggestions for future research and management directions.
The Tana River is the longest river system in Kenya (~1000 km) and contributes ~ 50% of the total... more The Tana River is the longest river system in Kenya (~1000 km) and contributes ~ 50% of the total river discharge to Kenyan coastal waters. The river discharges significant amounts of nutrients and sediments, reaching ~24,000 tons per day during the rainy season (March-April), into Ungwana Bay (North Kenya Banks). The bay is an important habitat for high-value Panaeid prawn species which sustain important small-scale fisheries, semi-industrial bottom trawl prawn fisheries, and is the livelihood mainstay in the surrounding counties. In this study we analysed >20 years of satellite-derived chlorophyll-a observations (Chl-a, an index of phytoplankton biomass), along with in situ river discharge and rainfall data, to investigate if the Tana River discharge is a major driver of local phytoplankton biomass in Ungwana Bay and for the neighbouring Kenyan shelf. We find that during the rainy inter-monsoon (March-April), a significant positive relationship (r = 0.63, p < 0.0001) exists between river discharge and phytoplankton biomass. There is a clear time-lag between rainfall, river discharge (1-month lag) and local chlorophyll biomass (2-months lag after discharge). Unlike offshore waters which exhibit biannual chl-a peaks (0.22 mg m − 3 in February, and 0.223 mg m − 3 in August/September), Ungwana Bay displays a single peak per annum in July (2.51 mg m − 3), with indications that river discharge sustains phytoplankton biomass for several months. Satellite-derived observations and Lagrangian tracking simulations indicate that higher Chl-a concentrations remain locally within the bay, rather than influencing the broader open waters of the North Kenya Banks that are mainly impacted by the wider oceanic circulation.
International Journal of Research and Engineering, 2018
The cost, availability and stability of power are parameters that greatly define the quality of e... more The cost, availability and stability of power are parameters that greatly define the quality of energy supplied by a generating system. A hybrid power system with different sources of energy must be properly designed in order to capitalize on the positive features of the deployed resources. Hybrid power system optimization is a process that allows for deliberate attainment of desired output from a power system. In this paper, a learning institution, East African School of Aviation (EASA) was selected as a case study for investigating the outcome of harnessing local energy resources to serve a commercial consumer in Kenya. A cost competitive hybrid power system was obtained through Simulation and optimization processes.
Cardio-metabolic disease is a leading cause of death worldwide, with extremely high prevalence in... more Cardio-metabolic disease is a leading cause of death worldwide, with extremely high prevalence in western, industrialized societies relative to developing nations and subsistence-level populations. The high prevalence in western societies has been attributed to dietary and lifestyle changes associated with industrialization, but current work has relied on health comparisons between separate, genetically distinct populations to draw these conclusions. To more robustly determine how lifestyle affects cardio-metabolic health, we collected interview and biomarker data from a single population undergoing a rapid lifestyle transition. We sampled individuals of the Turkana tribe who practice subsistence-level, nomadic pastoralism (the traditional, ancestral way of life for this group) versus individuals who no longer practice pastoralism and engage either minimally or strongly with the market economy. Comparisons across this lifestyle gradient revealed clear, non-linear effects of industri...
Cassava bacterial blight (CBB), caused by Xanthomonas axonopodis pv. manihotis (Xam), is the most... more Cassava bacterial blight (CBB), caused by Xanthomonas axonopodis pv. manihotis (Xam), is the most important bacterial disease of cassava. There is no information available on the morphological and genetic variability of Xam isolates from Kenya. The aim of this study therefore, was to determine the diversity of Xam isolates from different cassava growing regions of Kenya using phenotypic characteristics and repetitive DNA polymerase chain reaction-based fingerprinting (rep-PCR). Thirty three isolates were recovered from infected cassava leaf samples collected from farmers' fields in cassava growing regions. The dendrogram generated from analysis of phenotypic characteristics of the isolates produced two major clusters at 75% similarity level. Analysis of 19 isolates with repetitive extragenic palindromic (rep) primers yielded characteristic fingerprint pattern with bands ranging between 400 and 2000 bp in size and their numbers ranged from 1 to 6 bands per isolate. Cluster analysis using unweighted pair group method with arithmetic averages (UPGMA) did not reveal any significant differences in clustering and relationship to the geographical origin, with exception of a single isolate that had unique fingerprints. These findings indicate that Xam population in Kenya evolved from the same origin and is a uniform population, and this may prove useful in future breeding programmes.
Inflammation causes discomfort, suffering and lower productivity of the victims. Synthetic anti-i... more Inflammation causes discomfort, suffering and lower productivity of the victims. Synthetic anti-inflammatory drugs are not readily available and have adverse side effects. Alternative herbal medicines possess bioactive compounds that are safer and efficient in the management of various diseases and disorders. The present study evaluated for the anti-inflammatory activity of methanolic extracts of Kigelia africana and Acacia hockii in mice to scientifically validate their traditional use among the Embu and Mbeere communities in Kenya. The plant samples were collected with the help of local herbalists in Embu County, Kenya and transported to Kenyatta University biochemistry and biotechnology laboratories for cleaning, air drying, milling, and extraction. Swiss albino mice of either sex were randomly divided into six groups of 5 animals each; normal control, negative control, positive control and three experimental groups. The anti-inflammatory activity was tested using carrageenan-induced hind paw edema method. The anti-inflammatory activity of the extracts was compared to reference drug diclofenac. The leaf extract of K. africana reduced inflamed hind paw diameter of mice by between 0.21%-4.98% while the stem bark extract of A. hockii reduced inflamed hind paw diameter by between 0.6%-5.38%. The diclofenac reduced inflamed hind paw diameter by between 1.11%-4.9%. The qualitative phytochemical screening indicated the presence of saponins, flavonoid, alkaloids, terpenoids, phenolics, and cardiac glycosides. The present study demonstrated potent antiinflammatory activities of methanolic extracts of K. africana and A. hockii in a dose-dependent manner, which supports their traditional use. The present study, therefore, recommends the ethnomedicinal use of K. africana and A. hockii in the management of inflammation.
Due to emergence of microcontrollers which enable real-time logging, viewing and analysis of data... more Due to emergence of microcontrollers which enable real-time logging, viewing and analysis of data, many new generation data acquisition products have been developed. There is an increasing demand for an improved, efficient and up-to-date microcontroller-based data logger.In this study, a microcontroller-based data logger was developed to measure the wind speed and direction using anemometer and wind vane sensors respectively. The collected data was transmitted to a Personal Computer (PC) through an RS-232 serial interface, which was processed using the 208W Data logger support software and stored in EEPROM memory for post process analysis. In order to test the effectiveness of the logger, wind data measured by the microcontrollerbased data logging system were analyzed through plotted line graphs, simple linear regression charts and wind rose diagrams.The correlation indices for the two three sets of wind speed data in the morning, midday and evenings were 0.997, 0.997 and 0.999 respectively. The wind speed measured by the calibrated sensor correlated well with JKUAT Meteorological data. The strong correlation indicated that developed system was effective and appropriate for measuring wind speed and direction. The system being automated, accurate, appropriate and at the same time cost effective, has potential use in weather forecasting, wind power plants, chemical manufacturing process and in airports among other applications. Further studies can be done to find the relationship between the wind speed and the frequency response of the encoder by use of a wind tunnel.
International Journal of Healthcare Management, 2013
Entrepreneurship studies are highly necessary in the healthcare field, as nowadays, managers perf... more Entrepreneurship studies are highly necessary in the healthcare field, as nowadays, managers perform entrepreneurial activities to generate innovative strategies in order to obtain a competitive advantage in the turbulent healthcare environment. Despite this industry faces complexity and growing competition, healthcare providers have been rarely analysed from the entrepreneurial point of view. As very little is known about this topic, we use a multiple-case studies approach to inductively develop propositions. This study applies the construct of entrepreneurial orientation (EO) in the context of private healthcare organizations. This research serves as an initial attempt to account for the determinants of some dimensions of EO in healthcare organizations, in order to comprehend how innovativeness, risk-taking, and proactiveness performs. We also consider the effect of family involvement and of the professionalization phenomenon in secondor subsequentgeneration firms on the EO of family-owned healthcare organizations.
American Journal of Physics and Applications, 2015
Wind turbine rotors capture energy from moving wind, their capacity to perform this function depe... more Wind turbine rotors capture energy from moving wind, their capacity to perform this function depends on the coefficient of power (Cp) of the rotor. Through proper aerodynamic design, a rotor's performance can be optimized to take advantage of the smallest available wind speed at any time to produce energy. In this research a computational fluid dynamics simulation was performed to model the best optimum dimensions of an inversely tapered rotor blade using Clark Y airfoil type rotor of 0.6 m diameter. The optimal design values obtained include; tip speed ratio (TSR) of 2.5, lift coefficient to drag coefficient ratio of 1.1 and pitch angle of 8 degrees Using blade element momentum (BEM), the wing profile of each section of the blade was calculated and designed. The unique inverse tapering was done to achieve a better efficiency at the low wind speed range. This was used to fabricate a three blade rotor using carbon composites which was tested in the wind tunnel for Cp. Results showed very good performance of the inverse tapered type as compared with the tapered rotors. The maximum coefficient of power for the inversely tapered was found to be 0.313 at 8 m/s. Visualization test and particle image velocimetry (P.I.V). analysis showed that the inversely tapered rotor is more effective in converting wind power into shaft power than the tapered.
Cassava is ideal for biofortification due to its popularity as a root staple among populations wi... more Cassava is ideal for biofortification due to its popularity as a root staple among populations with high vitamin A malnutrition. The crop is vegetatively propagated and retains the enhanced trait across generations. The combining ability for beta-carotene content and important yield trait was evaluated in a cassava F1 generation. Ten high beta-carotene clones from International Institute of Tropical Agriculture (IITA) were hybridized with ten local clones in a North Carolina Design II mating design. The F1 population was evaluated at the Kenya Agricultural Research Institute (KARI). A total of 125 families were evaluated, including 35 reciprocal crosses. The IITA parents had highly significant (P ≤ 0.001) General Combining Ability (GCA) for pulp colour and plant height. The GCA of the local parents was significant (P≤ 0.05) for harvest index, number of lobes (P≤ 0.05) and for plant height (P≤ 0.001). The Specific Combining Ability (SCA) was significant for harvest index and plant he...
Most of the wind analysis studies have been conducted under steady wind conditions. The study of ... more Most of the wind analysis studies have been conducted under steady wind conditions. The study of real unsteady wind environment, however, is still an open-ended research question. This is attributable to the existing aerodynamic complexities under such conditions. In this paper, therefore, a numerical approach to investigate wind energy potential under unsteady conditions was proposed. In carrying out the study, the wind characteristics for two rural-urban towns in Kenya, namely Marsabit (2 19 0 N, 37 58 0 E) and Garissa (0 28 0 S,39 38 0 E), were selected. A CFD analysis method was used to evaluate both unsteady wind inflow performance and the flow physics that affects the performance on a Vertical Axis Wind Turbine (VAWT). Using the validated CFD model, unsteady wind simulations were performed and the results obtained compared with empirical methods. Compared to the prevailing methods, the proposed numerical approach is not only computationally inexpensive, but also robust in both steady and unsteady wind conditions. The numerical method demonstrates that Garissa station is unsuitable for gridconnected power generation, while Marsabit station is suitable for both grid-connected and standalone power generation activities. The study results will hopefully be of importance to the wind industries that require designs for wind turbines reflecting real unsteady wind environment.
Theileria parasites cause a benign infection of cattle in parts of Australia where they are endem... more Theileria parasites cause a benign infection of cattle in parts of Australia where they are endemic, but have, in recent years, been suspected of being responsible for a number of outbreaks of disease in cattle near the coast of New South Wales. The objective of this study was to identify and characterize the species of Theileria in cattle on six farms in New South Wales where disease outbreaks have occurred, and compare with Theileria from three disease-free farms in Queensland that is endemic for Theileria. Special reference was made to sub-typing of T. orientalis by type-specific PCR and sequencing of the small subunit (SSU) rRNA gene, and sequence analysis of the gene encoding a polymorphic merozoite/piroplasm surface protein (MPSP) that may be under immune selection. Nucleotide sequencing of SSU rRNA and MPSP genes revealed the presence of four Theileria genotypes: T. orientalis (buffeli), T. orientalis (ikeda), T. orientalis (chitose) and T. orientalis type 4 (MPSP) or type C (SSU rRNA). The majority of animals showed mixed infections while a few showed single infection. When MPSP nucleotide sequences were translated into amino acids, base transition did not change amino acid composition of the protein product, suggesting possible silent polymorphism. The occurrence of ikeda and type 4 (type C) previously not reported to occur and silent mutation is thought to have enhanced parasite evasion of the host immune response causing the outbreak.
15th International Workshop on Research and Education in Mechatronics (REM), 2014
This paper investigates a feasibility measurement study for wind resource and a numerical simulat... more This paper investigates a feasibility measurement study for wind resource and a numerical simulation for wind regimes of Marsabit and Garissa stations, both rural-urban towns in Eastern region of Kenya. The experimental wind speed measurement was done using optical anemometer sensors while the wind direction was detected by wind vane sensors. The data logging instrumentation with calibrated wind sensors recorded higher resolution wind data. Based on the wind regimes at the sites, an analysis of aerodynamic performance and flow physics of two-dimensional numerical simulations on a NACA0015 airfoil was done using CFD FLUENT software. The Meteorological wind speed measurement correlated with the calibrated cup anemometer sensors measurement with a correlation coefficient of 0.98. The strong correlation confirms that the experimental anemometer gave the correct readings and practical readings can be approximated to the data from the meteorological station. The wind regimes showed attached flow acceleration over the airfoil surface for various angles of attack. The results provide a reference to the research and development of vertical axis wind turbine for target markets.
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Papers by Joseph kamau