Nordman E.E.,Kenyatta University |
Nordman E.E.,Grand Valley State University
Renewable Energy | Year: 2014
Kenya's tea sector provides livelihoods for more than 500,000 farmers but energy access in the region remains limited. Clean, affordable distributed energy systems could transform the tea-growing regions by lowering tea production costs and increasing farmer profits. On-site generation could power tea factories and enhance grid stability by reducing electricity draw from the grid. Wind power's potential in Kenya's tea regions is unknown. A pre-feasibility study using the Solar and Wind Energy Resource Assessment (SWERA) data set revealed that 29% of Kenya's tea factory sites have wind resources that could be suitable for development. There were more "moderate"-rated tea factory sites west of the Rift Valley, but tea factories east of the Rift Valley had greater wind resources. Economic analysis using RETScreen found that wind power in the eastern region had a positive net present value (NPV) under a wide range of assumptions. In the base case, a 750kW wind turbine with a capital cost of US$1.5 million (US$1984/kW) at the most suitable tea factory had an NPV of US$515,779. The life cycle cost of energy at this location was estimated at $0.156/kWh. SWERA data are conservative and may underestimate the wind resource at some locations. End use demand in the tea sector is driving the transition to distributed, renewable energy in Kenya's tea-growing regions. Whether this development can catalyze a positive feedback loop with spillover benefits to energy-poor rural communities remains to be seen. © 2014.
Runo S.,Kenyatta University
Bioengineered Bugs | Year: 2011
RNA interference (RNAi) has rapidly advanced to become a powerful genetic tool and holds promise to revolutionizing agriculture by providing a strategy for controlling a wide array of crop pests. Numerous studies document RNAi efficacy in achieving silencing in viruses, insects, nematodes and weeds parasitizing crops. In general, host derived pest resistance through RNAi is achieved by genetically transforming host plants with double stranded RNA constructs targeted at essential parasite genes leading to generation of small interfering RNAS (siRNAs). Small interfering RNAS formed in the host are then delivered to the parasite and transported to target cells. Delivery can be oral-worms and insects, viral infections, viruses-or through vascular connections- parasitic plants, while delivery to target cells is by cell to cell systemic movement of the silencing signal. Despite the overall optimism in generating pest resistant crops through RNAi-mediated silencing, some hurdles have recently begun to emerge. Presently, the main challenge is delivery of sufficient SİRNAS, in the right cells, and at the right time to mount; a strong, durable and broad-spectrum posttranscriptional gene silencing (PTGS) signal. This review highlights the novel strategies available for improving host derived RNAi resistance in downstream applied agriculture. © 2011 Landes Bioscience.
Ishugah T.F.,Shanghai JiaoTong University |
Li Y.,Shanghai JiaoTong University |
Wang R.Z.,Shanghai JiaoTong University |
Kiplagat J.K.,Kenyatta University
Renewable and Sustainable Energy Reviews | Year: 2014
Wind energy continues to stand out as a more established and mature technology to offset a large proportion of power. Efforts aimed at improving wind energy use to meet the energy demand in turbulent urban wind environment have been the main technical focus. In previous studies on wind resource and behavior in urban environment, different designs of horizontal axis wind turbines (HAWTs) and vertical axis wind turbines (VAWTs) have been reviewed. This paper vividly captures the fact that wind resource has a great potential to be fully explored and developed in the urban environment. Varying ways of application and application techniques being applied for electrical generation, ventilation and pollution dispersion, onshore cooling and dehumidification of coastal urban cities, and economics and environmental benefits of applying wind energy in urban environments are summarized. Although many new ideas and solutions that factor technical, economical and environmental sustainability in urban areas are coming up every day, challenges in design are gradually being solved to take advantage of urban low and turbulent wind speed characteristics, installation space challenges, vibration and noise reduction, among others. Some of the unique solutions that have been and are being developed in the applications of wind energy technology in urban environments are also reported in this paper. © 2014 Elsevier Ltd.
Onywera V.O.,Kenyatta University
Global health promotion | Year: 2010
Childhood obesity continues to be a serious public health problem across the globe. The problem is increasingly affecting both developing and developed countries alike, albeit at different rates. In Africa, the problem seems to be aggravated by the nutrition and physical activity transition currently taking place, which is leading to an increase in the use of energy-saving devices, the availability of cheap high-calorie dense foods and limited participation in physical activity at home and at school. The situation is complicated by socio-cultural beliefs in which obesity and overweight are admired traits and seen as a sign of wealth, prestige and the 'good life'. Efforts and strategies are therefore needed in order to address the child obesity problem which is starting to show among most African countries. This paper gives some possible strategies which might help in preventing the child obesity and physical inactivity threat in Africa.
Nyamache A.K.,Kenyatta University
BMC research notes | Year: 2014
METHODS: A cross sectional study was conducted at Thika district level 5 hospital, Kenya to investigate seroprevalence of CMV infections and associated possible risk factors among pregnant women. Structured questionnaires were used to gather socio-demographic data and ELISA was used to detect CMV infections using IgG and IgM.RESULTS: Out of 260 pregnant women, 201 (77.3%) were CMV IgG 21(8.1%) CMV IgM being on acute stage of the disease. Marital status (OR = 3.7533, 95% CI =3.0231-6.9631, P < 0.0001), parity (OR = 3.7533, 95% CI = 3.0231-6.9631, P < 0.0001), and education (OR = 3.7533, 95% CI = 3.0231-6.9631, P < 0.0001), history of blood transfusion (OR = 0.0374, 95% CI = 0.00120-0.1168, OR = 0.3804) were found to significantly influence seropostivity in univariate analysis.CONCLUSION: The 88.4% CMV prevalence rate being detected among pregnant women calls for vaccine and routine screening for CMV infections and its associated risk factors in this kind of settings.BACKGROUND: The fetal consequences of CMV infection have made it one of the most serious infections contracted during pregnancy. Despite the posed teratogenic risk during pregnancy, there is no national screening test for CMV infection is available during pregnancy in Kenya. Thus little is known on its epidemiological data that is necessary for health planners and care providers.