PhD Graduands

Abstract: 

In the recent decades, extreme weather events have increased in frequency, intensity and magnitude threatening and increasing the vulnerability of rural livelihoods particularly in the arid and semi-arid lands. This study explored climate change events, the extent of their impacts on farmers’ livelihoods, farmers’ adaptation strategies and the extent of the strategies on improving farmers' ability to manage the climate change impacts in the Yatta region, Kenya. The study adopted a multi-method approach that integrated qualitative and quantitative data sources. Quantitative data were obtained from 354 household interviews while qualitative data were obtained from 8 focus group discussions. The interview data were analyzed using descriptive and inferential statistics while the discussion data were analyzed using qualitative content analysis. The most experienced climate events were drought (90.7%), crop diseases (79.1%) and floods (33.30%). Livelihoods aspects greatly impacted by the climate change events were food shortage (87.29%), increased food prices (76.27%) and decreased availability of water (72.43%). Although farmers had adopted several on-farm adaptation strategies, the adoption levels remained low. Water management strategies (water conservation and water harvesting) recorded higher adoption rates of 62.71% and 53.95% respectively. The adoption of on-farm adaptation strategies had proved some potential to improve farmers’ ability to deal with the experienced climate change impacts. The regression model showed that farmers were likely to adopt crop and water management practices which they perceived had a higher probability of improving their ability to cope with climate change impacts. The occurrence of climate change events in the study area has affected agriculture productivity, food security and socioeconomic status of the households. Effective integration of potential adaptation strategies into smallholder farming systems calls for measures to address adoption and implementation barriers while ensuring alignment of policies, programs and institutional support systems.

Abstract:

Informal microfinance is the delivery of financial services mainly to low income people outside the

regulation of the monetary authority. Despite their importance in development, no studies have

undertaken a detailed analysis of structures and performance

in informal microfinance institutions.

This study aims to analyze structures and performance in informal microfinance institutions in

Tharaka South Sub County. It uses descriptive study design and multi stage sampling design. Data

analysis was done using thematic, descriptive and Kendall’s tau

-b correlation analysis. An informal microfinance performance index was developed using inductive and hierarchical approaches. The study found the informal microfinance institutions are marked by high performance which

isdetermined by their structures. Moreover, the study deduced that informal microfinance is a key

policy strategy for poverty alleviation, financial inclusion, gender equity and resilience building since

participants mainly include women and other vulnerable groups.

Abstract: 

Penicillin residues in animal food products like milk and meat has attracted great concern by health

regulatory agencies due to their negative effects. Therefore, there is urgent need for reliable, low cost,

fast and simple analytical tools/methods to monitor these penicillin residues in animal products before

distribution to consumers. In our previous work, we developed a square wave voltammetric method

based on bare glassy carbon electrode in SDS/ABS media to determine penicillin V and G. In this work,

we apply this voltammetric method to detect penicillin G at trace levels in cow milk and selected

pharmaceutical samples. Using cyclic voltammetry, the electrochemical behavior of penicillin G in both

cow milk and pharmaceutical samples were obtained. The oxidation potentials were 1.65V in both

samples, same as that obtained in SDS/ABS media. The diffusion coefficients were 1.494x10-6cm2/sec

in cow milk, 2.358x10-7cm2/sec in pharmaceutical sample and 1.392x10-6cm2/sec in SDS/ABS media.

The precision for the detection of the drug was also determined and recorded as relative standard

deviation (RSD). The RSD found were 4.22% and 5.51% for cow milk and pharmaceutical sample

respectively. The percent recoveries for accuracy determination were found to lie between 95.8% -

103.0% for the cow milk and 92.0% - 96.0% for the pharmaceutical samples. These recovery percentages

were within the recommended 90.0% - 110.0%. A detection limit of 2.5×103 ng/L penicillin G was

achieved in cow milk samples against a maximum residue limit of 4.0×103ng/L set by the European

Union. Overly, this method provides simple, precise and consistent results for detection and

quantification of penicillin G in cow milk, pharmaceuticals and possibly other environmental and clinical

samples.

Abstract: Artisanal gold-mining (AGM) is one of the most important activities in the districts of Migori and Transmara (Kenya). Gold-mining, however, is known to release vast quantities of arsenic and metals (some of which are very toxic like As, Hg, Cd, or Pb), which poses a serious threat to not only miners but also to the ecosystem and local populations. We, herein, determine the concentrations of arsenic and some heavy metals in several sample types (i.e., ore, soil, river sediment, and mine tailing) collected from the districts of Migori and Transmara. We also employ lichens and mosses as pollution bioindicators. Geostatistical tools and canonical correlation analysis were used to identify the relevant factors that affected arsenic and metal concentrations in the analysed samples. The following concentration ranges were reported in topsoil: As (1–17,250 mg kg−1), Cd (0.01–15.10 mg kg−1), Cu (7–9,238 mg kg−1), Cr (1–214 mg kg−1), Ni (5–766 mg kg−1), Pb (3–1,149 mg kg−1), and Zn (22–1,271 mg kg−1). It was concluded that the ecosystem in both districts was highly polluted by heavy metals whereas the arsenic concentrations in topsoil were among the highest reported worldwide. The results of this study provide new evidence on the impact of AGM on the environment and may further contribute to the design of policy measures with the aim of reducing environmental and human health risks associated to AGM activities.

Abstract: Community vulnerability to climate change can be conceptualized as an aggregate of three vulnerability components: exposure to climatic stress, sensitivity to climate stress and adaptive capacity. However, even within similar regions these vulnerability components are spatially differentiated necessitating the understanding of a regions vulnerability pattern before targeting adaptation assistance. This research sought to understand the differentiated vulnerability patterns of communities in Kitui County as well as the existing coping strategies to guide implementation of adaptation assistance. Indicator approach to vulnerability assessment and focus group discussions were used to understand the vulnerability pattern and coping strategies respectively. Results showed a differentiated vulnerability pattern with a west to east gradient across Kitui County. The pattern exhibited less vulnerability scores on the western and central parts and more vulnerability scores on the eastern and northern parts of the County. Existing coping strategies have become inadequate with increasing climate variability, severity and frequency of extreme climate events, which render the communities even more vulnerable. The patterns of vulnerability can guide appropriate targeting of adaptation assistance and in turn lead to improved climate change resilience and community livelihoods.

Rock geochemistry influences groundwater quality and the aquifer processes of an area. The geology of the study area comprises quartzo-feldspathic gneiss and biotite gneiss of the Precambrian basement, sedimentary Turkana Grits and Holocene sediments, Tertiary volcanics comprising nepheline phonolites and augite basalts, alluvial deposits along the banks of major streams and laggas (ephemeral streams), and Quaternary sands that blanket much of the area. This paper evaluates the influence of rock chemistry on groundwater quality in Lodwar area. Conventional petrography and geochemistry techniques involving measurement of major elements using X-ray fluorescence (XRF) and trace elements using and X-ray diffraction (XRD) in 69 rock samples to evaluate their mineralogical compositions. The major rock-forming in rocks of the study area include pyroxenes, olivine, kaolinite, siderite, fluorite calcite and dolomite. These minerals release major ions to groundwater through weathering, leaching, oxidation, dissolution and precipitation, and ion exchange reactions during rock-water interactions. The rocks in study area have generally low amounts of Na and K with modal values < 2.00 wt%, suggesting other sources of Na+ and K+ ions in groundwater. In contrast, Ca, Mg, Al, Fe and Mn are released to groundwater from rocks, as shown by high modal compositions of individual elements and associated oxides. The higher concentrations of Na+, K+, Ca2+ and Mg2+ in the groundwater of the Turkana Grit aquifer relative to the grit rock samples suggest a long history of dissolution and recycling of the groundwater. The ratio SiO2:Al2O3 was found to be greater than 8.0 implying a high degree of maturity of the grits. The results presented by this study show that geological factors and processes have location-specific influence on groundwater quality and should be considered in aquifer water quality studies and supply development across Africa’s vast ASAL regions.

Abstract: Climate change poses significant risks to food security globally with predictions of 10-20 % decline in rain-fed crop yields by 2050. Sub-Saharan Africa remains highly susceptible to food shortage since over 95 % of the region’s total cropland is rain-fed. Kenya’s over reliance on rain-fed agriculture predisposes the country to climate-induced food insecurity. Murang’a County in Kenya is experiencing climate change challenges manifested in prolonged droughts and floods. The consequences,are failed cropping seasons, soil erosion, landslides, altered crop suitability and a resurgence of human, livestock, crop pests,and diseases,culminating into food insecurity. This study was conducted with Kimandi-Wanyaga community in the Gatanga Sub-County in Murang’a County, Kenya. Residents are smallholder subsistence rain-fed farmers. The study explored the potential of up-scaling crop diversification under the Plantation Establishment and Livelihood Improvement Scheme (PELIS) for food security vis-à-vis climate change. The community’s climate change coping strategies were explored to account for the need to up-scale crop diversification under PELIS. A mixed methods research design was applied whereby a systematic sampling method was used to select 281 household-heads. Three key informants were purposively selected and primary data were collected through a household survey, in-depth key stakeholder interviews, focus group discussions and on-farm trials. Quantitative data were analysed using descriptive and inferential statistics while qualitative data were analysed using thematic and content analysis. The study established that 92.9 % of the community perceived climate change and its impacts. They had adopted a combination of coping strategies most of which,were found to be informed by short-term survival and hence,considered inadequate for long-term adaptation. The PELIS approach had been piloted in Murang’a County and was found to be a promising strategy for crop diversification and food security among forest-adjacent communities. However, only 11 % of the studied community participated in the scheme. Therefore, the study endeavoured to work with the community to promote cultivation of traditional vegetables under PELIS for crop diversification and food security in the face of climate change.The PELIS beneficiaries who adopted cultivation of Black nightshade, Amaranths and Cowpeas managed to produce enough for household consumption and sale of surplus for income. The PELIS,therefore, possesses the co-benefits of climate change adaptation through crop diversification for food security and climate change mitigation through afforestation for carbon sequestration.

Abstract: Many studies conducted in Kenya regarding water resource governance have focused on the mandate of Water Resource Users Associations (WRUAs) with less attention being accorded to their effectiveness in conservation of wetlands. This study assessed the effectiveness of WRUA committees, and challenges faced in conservation of Rwamuthambi Sub-catchment. The study employed exploratory descriptive research design. Data was collected through questionnaires, semi-structured interviews, observations and review of secondary data. Chi square and descriptive statistics was used to analyze the data. The survey results revealed that only 15% of WRUA committee understood water resources management while 35% were aware of relevant legislations. Factors of wetland degradation showed significant association with existence of WRUA (χ2 (4, N=180) = 20.46, p< .01) where (χ2- chi square (degrees of freedom, N = sample size) = chi-square statistic value, p = p value), although WRUA contributions were perceived differently per agro-ecological zone (χ2 (8, N=147) = 15.51, p>.05). Challenges unearthed were inadequate financial and human resources, lack of understanding, ineffective collaborative governance, poor support from county government and private ownership of riparian land reserve. There is need for WRUAs to embrace collaborative governance for effective conservation of wetlands. Integration of sub catchment management plan with county land use plans and policy review is also required.

Abstract: 

With reference to a confounded asymmetrical design for an  factorial experiment, a very powerful tool for expressing factorial arrangements in a compact and convenient form has been given and also used in this paper in order to derive efficiency factors of the said designs. The concept of orthogonal factorial structure and balance has been explained and a characterization  for balance with orthogonal factorial structure has been given. An expression is derived for efficiency factors of linear contrasts. This expression involves Kronecker product matrices. An example is also given to show how efficiency factors of confounded asymmetrical factorial designs are calculated.

Keywords and phrases:

efficiency factors, Kronecker product matrices, linear contrasts, confounded asymmetrical factorial design, orthogonal factorial structure, balance.