Faculty of Science

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Access to water in Kenya’s coast region
(2018) Ignatius, David O.; Hassan, Farida A.; Morara, George N.; Osore, Melckzedeck k.; Mutua, Benedict M.; Kitaka, Nzula K.
Water is considered a basic commodity and essential for life - living on planet earth is dependent on it. However, access to water has been and will continue to be a dilemma for a majority of the residents at the coast of Kenya. A close look at the window on “Coastal Resources and People” reveals that water is a key resource but despite its immense importance, many people especially in the rural areas and among the Vulnerable and Marginalized Groups (VMG’s) do not have adequate access to potable, reliable and convenient sources of water. Lamu, currently considered among water scarce counties in Kenya as per the Lamu County Integrated Development Plan (http://lamu.go.ke/wp-content/uploads/2016/03/LAMU_CIDP-Revised.June_2014-1.pdf), faces serious challenge of provision of potable water to its residents. With the influx of people from other parts of the country as a result of the implementation of the Kenya Vision 2030 flagship project - Lamu Port Southern Sudan Ethiopia Transport (LAPSSET) Corridor, the current water stresses is only expected to worsen. The Lamu County Government plans to address the ever-increasing demand for access to water but resources to actualise these plans are yet to be consolidated. To complement this situation, Kenya Coastal Development Project (KCDP), a World Bank funded project is working with local communities in Lamu in the development and implementation of community-led water projects targeting to increasing access to water at the household level. This paper will focus on community-based approaches to understand the water-web in Lamu East Sub-County to provide an assessment of opportunities, challenges and sustainability implications. Primary data is used on surveys, Social Assessment (SA),Vulnerable and Marginalised Group Plan (VMGP), observations and recommendations from the Lamu CIDP. It further proposes that direct usage of saline water, seawater or brackish water, for sanitation purposes could alleviate the freshwater shortage.
Acute oral toxicity evaluation of some polyherbal formulations in albino wistar rats.
(Orgz, 2008) Vijayabalaji, V.; Joshua, Allan J.; Kumar, Pavan G.; Murali, B.; Suryanarayana, ML.; Siamba, Donald N.
The objective of the current study was to assess the acute oral toxicity of some herbal veterinary preparations in female albino Wistar rats as per the OECD guidelines for testing of chemicals, Acute oral toxicity-Fixed dose procedure (Test guideline 420). The investigational substances, NaturalivTM liquid and Zist® liquid are used in poultry for hepatoprotective and antioxidant properties, respectively. NaturalivTM liquid was tested at 5000 mg kg-1 b.wt., whereas Zist® liquid was evaluated in sequential manner to one animal each at 2000 and 5000 mg kg-1 b.wt. in the sighting study, followed by four animals at 5000 mg kg-1 b.wt. in the main study. The treated animals were observed for mortality (twice daily), adverse clinical signs (once daily), changes in weekly body weight gain and gross necropsy findings. All the treated animals survived throughout the study period.
Advances in composite integer factorization
(2013) Wanambisi, Aldrin W.; Aywa, Shem.; Maende, Cleophas.; Muketha, Geoffrey Muchiri.
In this research we propose a new method of integer factorization. Prime numbers are the building blocks of arithmetic. At the moment there are no efficient methods (algorithms) known that will determine whether a given integer is prime or and its prime factors [1]. This fact is the basis behind many of the cryptosystems currently in use.
Advances in composite integer factorization
(International Knowledge Sharing Platiform, 2013-01-01) Wanambisi, Adrin W.; Aywa, Shem; Maende, Cleophas; Muketha, Geoffrey Muchiri
In this research we propose a new method of integer factorization. Prime numbers are the building blocks of arithmetic. At the moment there are no efficient methods (algorithms) known that will determine whether a given integer is prime or and its prime factors[1]. This fact is the basis behind many of the cryptosystems currently in use.
Advances in composite integer factorization
(Mathematical theory and modelling, 2013) Wanambisi, Aldrin.; Aywa, Shem.; Maende, Cleophas.; Muketha, Geoffrey Muchiri.
In this research we propose a new method of integer factorization. Prime numbers are the building blocks of arithmetic. At the moment there are no efficient methods (algorithms) known that will determine whether a given integer is prime or and its prime factors [1]. This fact is the basis behind many of the cryptosystems currently in use.
Aerosol optical depth and precipitation rate projections over east africa utilizing self organizing map
(The International Journal Of Science & Technoledge, 2017-03-01) Makokha, John Wanjala; Angeyo, H.K.; Muthama, John Nzioka
Assessment of future aerosols impacts on both regional and global climate change requires a comprehensive projection tool that reliably provides information on aerosol evolution characteristics with high fidelity. In the current study, we propose an algorithm based on Self-Organizing Map (SOM) and Community Atmosphere Model 4 (CAM4) for long term Aerosol Optical Depth (AOD) and Precipitation Rate (PR) projections over East Africa. To start with, AOD and PR retrievals from Moderate Resolution Imaging Spectroradiometer (MODIS) and Tropical Rainfall Measurement Mission (TRMM) respectively were cross validated with simulation from CAM4 so as to assess the uncertainty between the measured and simulated retrievals from 2000 to 2014.The error analysis between CAM4 simulations and MODIS measurements (from 2000 to 2014)shows a close match where R2 varies from 0.58 to 0.83 with a corresponding RMSE of between 0.014 and 0.065 (for AOD). Likewise, the uncertainty between simulate and measured PR from CAM4 and TRMM showed an estimated R2 to range between 0.40 and 0.78 while the RMSE varied from 0.021 to 0.091 in the same period and study sites. Based on proposed SOM algorithm and simulated CAM4 retrievals over each study site, an increase of between 1.34-2.43 % for AOD and a decrease of between 1.03-1.98 % in PR are projected over the region by 2030.
Agriculture chemicals’ related hazards control
(KARI publication unit, 2014) Ondieki, JO.; Lanyasunya, TP.; Lokwaleput, IK.; Mutunga, TK.; Siamba, Donald N.; Bwire, JM.
IN recent years, food safety standards have become a more prominent issue for global trade in agricultural and food products (Jaffee and Henson, 2004a; and Josling et al., 2004). Of particular concern is the potential impact of food safety standards, whether promulgated by governments or private sector buyers, on the ability of developing countries to gain and maintain access to markets for highvalue agricultural and food products, especially in industrialised countries. In part this reflects the growing preponderance of these standards, but also more widespread recognition of the degree and manner in which trade flows can be affected. Concerns are greatest in the case of low-income countries, given their typically weaker food safety and quality management capacities that can thwart efforts towards export-led agricultural diversification and rural development. This paper explores the impact that food safety standards are having on the performance of developing countries with respect to agricultural and food product exports, drawing on a programme of research at the World Bank (see World Bank, 2005). While recognising that food safety and quality standards can act to impede exports, an attempt is made to ‘rebalance’ the policy debate in this area. The paper outlines how the proliferation and increased stringency of food safety standards is creating a new landscape that, in certain circumstances, can form a basis for the competitive repositioning and enhanced export performance of developing countries. In particular, the foundations of this competitive repositioning is explored and related, in turn, to the manner in which developing country governments and/or private sector suppliers respond to evolving standards.
Algebraic approach to composite integer factorization
(International journal of mathematics and statistics, 2013) Wanambisi, W.; Aywa, Shem.; Maende, C.; Muketha, MG.
There various algorithms that can factor large integers but very few of these algorithms run in polynomial time. This fact makes them inefficient. The apparent difficulty of factoring large integers is the basis of some modern cryptographic algorithms. In this paper we propose an algebraic approach to factoring composite integer. This approach reduces the number of steps to a finite number of possible differences between two primes.
Algebraic approach to composite integer factorization
(European Centre for Research, Training and Development : IJMSS, 2013-03-01) Wanambisi, Adrin W.; Aywa, Shem; Maende, cleophas; Muketha, Geoffrey Muchiri
There various algorithms that can factor large integers but very few of these algorithms run in polynomial time. This fact makes them inefficient. The apparent difficulty of factoring large integers is the basis of some modern cryptographic algorithms. In this paper we propose an algebraic approach to factoring composite integer. This approach reduces the number of steps to a finite number of possible differences between two primes.
Allelopathic potential of mexican sunflower [tithonia diversifolia (hemsl) a. gray] on germination and growth of cowpea seedlings (vigna sinensis l.)
(2015) Musyimi, D.M.; Okelo, L.O.; Okello, Victor Samuel; Sikuku, P.S.
Invasive plant species when introduced into new environments may result into a number of ecological problems (Howard et al., 2000). They may influence other species through pathways such as allelopathy or phytotoxicity (Samuel et al., 2005; Imeokpara and Okusanya, 1994; Ayeni et al., 1997). Allelopathy is the inhibitory or stimulatory effect of a plant on another by chemicals released from the donor plant to the environment (Taiwo and Makinde, 2005; Bano et al., 2012). Allelopathy is a process by which plants release chemical compounds in their vicinity (Rice, 1984). Studies have shown that different plant parts release toxic metabolites into the soil that affect adversely germination and growth of plants (Kumar et al., 2008).
Analysis of drought and wet-events using SWSI-based severity-duration-frequency (SDF) curves for the upper Tana river basin, Kenya
(Science Publishing Group, 2018-06-12) Raphael Muli Wambua, Raphael Muli; Mutua, Benedict M.; Raude, James Messo
Drought and wet-event patterns in the Upper Tana River basin have significantly been changing due to variation of climatic and human-induced factors. This paper presents the analysis of drought and wet-events using Severity-DurationFrequency (SDF) curves for the Upper Tana River basin, Kenya based on Surface Water Supply Index (SWSI). The extreme value EV1 (Gumbel) frequency distribution function was used to formulate SDF curves. The developed SDF curves were used to develop isoseverity maps for the basin. From the results, the event-probability show that likelihood of drought events increased linearly with increase in magnitude of SWSI while the return period of drought events increased exponentially with decrease in magnitude of SWSI. The findings show that the probability and magnitude, the return period and magnitude of drought have linear and exponential regression coefficients of 0.984 and 0.980 respectively. On the other hand the probability of wet-period events decreased linearly with increase in magnitude of SWSI while the return period of the events increased exponentially with increase in magnitude of SWSI with regression coefficients of the linear and exponential functions of 0.804 and 0.881 respectively. This indicates that both the drought and wet-events probability and magnitude, and the return period and magnitude have a strong correlation. Spatially, it was found that generally the river basin exhibit an increasing pattern in cumulative SWSI in south-eastern areas than the north-eastern and generally a more increase in extreme wet-events than droughts in the basin. The developed (SDF) curves are critical for design of hydrologic, hydraulic and water resources supply systems while the spatial event-patterns can be incorporated in prioritized mitigation of extreme events.
Analysis of drought effect on annual stream flows of river Malewa in the lake Naivasha basin, Kenya
(Radiance Research Academy, 2014-09-15) Kyambia, Marshal M.; Mutua, Benedict M.
The main parameters of drought phenomenon are the longest duration and largest severity for a desired return period. These parameters form the basis for designing water storage structures to cope with drought effects. In this study, these drought parameters were estimated using the probability based theory. The sample estimates of the mean, coefficient of variation, skewness, correlation and information on the probability distribution of flow sequence, were used as the basic input parameters. The truncation level was considered at mean level of the annual flow sequences of River Malewa in Lake Naivasha basin. In this basin, 100, 50, 10, 5 and 2-year droughts may persist continuously for 6, 4, 3, 2 and 1 years respectively. From the probabilistic approach for a normal probability distribution function, high values of coefficient of variation resulted in high values of the actual severity. The results show that there is drought severity in Lake Naivasha basin especially in parts experiencing high inter-annual variability in annual flow regimes.
Analysis of fecal coliform levels at watering points along the upper reaches of river Isiukhu in Kakamega county, Kenya
(2018-04-24) Kindiki, Sarah.; Kollenberg, Mario.; Siamba, Donald N.; Sifuna, Anthony.; Wekesa, Clabe.
Diarrheal diseases often attributable to poor sanitary conditions and fecal contamination of drinking water remain a leading cause of mortality for children younger than five years. Water contaminated with human faeces, for example from municipal sewage, septic tanks and latrines, is of particular concern. Animal faeces also contain microorganisms that can cause diarrhea. Kakamega County in Kenya has a diarrhea prevalence rate of 20.2%, which is the highest in the country; a good proportion of these cases are believed to be water borne. This study was designed to determine fecal coliform levels in water samples collected from watering points along the upper reaches of River Isiukhu in Kakamega County, Kenya. Fifty-four samples were collected between August and October 2015 from nine sampling points, comprising springs and watering points along the river. Water samples were filtered on nitrocellulose filters by vacuum filtration; fecal coliform counts were conducted using membrane filters cultured on mFC agar to establish contamination levels. The results indicated that counts ranged from 200 cfu/100 ml – 1450 cfu/100 ml in river sampling points and ranged from 0 cfu/100 ml – 44 cfu/100 ml in springs sampling points. The fecal coliform counts for River Isiukhu and most springs surrounding it exceeded the WHO recommended drinking water coliform (or E. coli) count value of 0 cfu/100 ml indicating that water from the upper reaches of River Isiukhu and springs is not fit for drinking before treatment, especially during the wet seasons, based on WHO drinking water standards.
Analysis of manual and centralised supervisory control operations to improve level of service: a case study of pyramid hill no 1 channel, Victoria, Australia
(Kluwer Academic Publishers, 2001-02) Malano, Hector M.; Mutua, Benedict M.
The current challenge facing irrigation inAustralia is tofind ways to improve the operationalperformance of existing systems rather thanconstructing new ones. Unsteady flowsimulation models are often used as keytools to study and test improvedoperational scenarios for existing systems.While these models are generally notrecommended for real-time control, researchhas shown that they are able to simulatecanal response for different test scenariosfor operations planning. This paperpresents the results of two alternativemodes of operation for the Pyramid Hill No.1 Channel in northern Victoria, Australia.The channel is currently under manualoperation. Centralised control is the mostimmediate option considered by theirrigation authority to enable remotesupervision and control of the canal toimprove the channel operation and level ofservice standards. This type of control istermed Supervisory Control and DataAcquisition (SCADA). The two alternativeoperational scenarios were simulated andanalysed using the unsteady flow-simulationmodel DUFLOW. Specific performanceindicators were defined to compare the twomodes of operations based on the simulationresults. The results show that SCADAoperation has considerable potential toclosely match the discharges at thedownstream regulator with those ordered byfarmers while maintaining the water surfaceelevations within allowable fluctuationtolerance throughout the length of thecanal.
Analysis of spatial and temporal drought variability in a tropical river basin using palmer drought severity index (PDSI)
(Academic Journals, 2017-08-31) Wambua, Raphael M.; Mutua, Benedict M.; Raude, James M.
Analysis of spatial and temporal drought variability in the upper Tana River basin using Palmer Drought Severity Index (PDSI) was conducted. The drought is critical for formulation of mitigation measures in the river basin. A monthly temporal and 90-m spatial resolution was applied. This was achieved within ArcGIS environment. Climatic data for 1970 to 2010 was used for computation of the PDSI while the missing data sets were filled using Artificial Neural Networks (ANNs). The results of PDSI for dry and wet seasons at meteorological stations indicate that the time series plots for the PDSI values for dry season are generally lower than those for the wet seasons. The PDSI values for meteorological stations located at the lower elevation of the basin are lower than those located at higher elevation. On the other hand, spatially distributed drought severity based on PDSI show that the ranges of maximum and minimum drought severity values in 1970 are -0.868 to -0.804 and -0.675 to -0.610 respectively. These values of drought severity occur respectively in the north-western and south-eastern areas of the basin. PDSI values increased from the range -0.675 to -0.610 in 1970 and from -1.087 to 0.957 in 2010 for the north-eastern areas of the upper basin. The south eastern areas of the basin are more prone to drought risks than north-western parts. Use of the PDSI reflects the spatial heterogeneity and temporal variability of drought across the basin. The drought assessment offer technical approach for comprehensive understanding of drought for effective drought-induced disaster mitigation and its management, with a view to reducing adverse effects on livelihoods.
Analyzing the Mara river basin behaviour through rainfall-runoff modeling
(Scientific Research Publishing, 2017-09-14) Birundu, Anne M.; Mutua, Benedict M.
Hydrological models are considered as necessary tools for water and environmental resource management. However, modelling poorly gauged watersheds has been a challenge to hydrologists and hydraulic engineers. Research done recently has shown the potential to overcome this challenge through incorporating satellite based hydrological and meteorological data in the measured data. This paper presents results for a study that used the semi-distributed conceptual HBV Light Model to model the rainfall-runoff in the Mara River Basin, Kenya. The model simulates runoff as a function of rainfall. It is built on the basis established between satellite observed and in-situ rainfall, evaporation, temperature and the measured runoff. The model’s performance and reliability were evaluated over two sub-catchments namely: Nyangores and Amala in the Mara River Basin using the Nash-Sutcliffe Efficiency which the model referred to as Reff and the coefficient of determination (R2 ). The Reff for Nyangores and Amala during the calibration and (validation) period were 0.65 (0.68) and 0.59 (0.62) respectively. The model showed good flow simulations particularly during the recession flows, in the Nyangores sub-catchment whereas it simulated poorly the short term fluctuations of the high-flow for Amala sub-catchment. Results from this study can be used by water resources managers to
Antimicrobial Coumarins from the Oyster Culinary-Medicinal Mushroom, Pleurotus ostreatus (Agaricomycetes), from Kenya
(International Journal of Medicinal Mushrooms, 2016-01-01) Baraza, Lilechi D.; Wekesa, Wekesa; Korir, Cheruiyot Jackson; Juma, Fredrick B.; Ochieno, Dennis; Wairimu, Kamau R.; Osogo, Aggrey; Heydenreich, Matthias
Pleurotus ostreatus has been widely used as food because of its nutritional and medicinal properties. These have been attributed to the presence of macronutrients, minerals, vitamins, and amino acids, among other secondary metabolites. There are, however, few reports on the antimicrobial activities of different classes of purified compounds from P. ostreatus. This led to the current study, the objective of which was to chemically characterize the antibiotic activities of P. ostreatus against selected human pathogenic bacteria and endophytic fungi. Chemical structures were determined using spectroscopic methods and by comparison with values of related structures reported in the literature. Pure compounds from P. ostreatus were tested in vitro against pathogenic bacteria (Staphylococcus aureus and Escherichia coli) and endophytic fungi (Pencillium digitatum and Fusarium proliferatum). A new compound, (E)-5,7-dimethoxy-6-(3-methylbuta-1,3-dienyl)-2H-chromen-2-one (5-methoxy-(E)-suberodiene) (compound 2), along with ergosterol (compound 1) and 5,7-dimethoxy-6-(3-methylbut-2-enyl)-2H-chromen-2-one (toddaculin; compound 3), were isolated from the fruiting bodies of P. ostreatus. The growth of S. aureus, F. proliferatum, and P. digitatum colonies was inhibited in media containing compound 2, with minimum inhibitory concentrations closely comparable to those of conventional antibiotics.
Application of ultrasonography in prevalence studies of hydatid cysts in goats in north-western Turkana, Kenya and Toposaland, southern Sudan
(Elsevier, 2000) Njoroge, Ernest M.; Mbithi, P.M.F.; Gathumat, J.M.; Wachira, M; Magambo, J.K.; Zeyhle, E.
Application of ultrasonography in prevalence studies of hydatid cysts in goats in north-western Turkana, Kenya and Toposaland, southern Sudan. Onderstepoort Journal of Veterinary Research, 67:251-255 A study was done to determine the prevalence of hydatid cysts in goats using ultrasonography. A total of 1 390 goats were examined, 43,6 % (606/1390) of them from north-weste_rn Tu_rkana, Keny:, and 56,4% (784/1390) from Toposaland, southern Sudan. Hydatid cysts were VISualized 1n 1,82 Yo (~ 1 I 606) of the goats from north-western Turkana and 4,34% (34/784) of those from Topo~aland. Unlike abattoir surveys, the prevalence data obtained in this study were unb1ased because ent1re flocks were examined. The lower prevalence rate of the disease in goats from Turkana was attnbuted to the hydatid disease control programme in that area, which is absent in Toposaland .
Aspects of (p.q) summing multipliers
(Vdm verlag Dr. Muller aktiengeselischaft & co. kg., 2010) Aywa, Shem.; Agure, J.O.; Rao, W.
A sequence (uj )j∈N of operators in L(X, Y ) is a (p, q)-summing multiplier (or (p, q)-summing sequence of operators), in short (uj ) ∈ `πp,q (X, Y ), if there exists a constant C > 0 such that, for any finite collection of vectors x1, x2, . . . xn in X, it holds that ³Xn j=1 kujxjk p ´1/p ≤ C sup n³Xn j=1 |x ∗ xj | q ´1/q ; x ∗ ∈ BX∗ o . Some examples of these operators, inclusions between the spaces and connections with spaces of multipliers are presented.∗ Mathematics Subject Classification (2000): 47B10. Key words: Summing operators, vector-valued multipliers. 1. Introduction. Let X and Y be two real or complex Banach spaces and let E(X) and F(Y ) be two Banach spaces whose elements are defined by sequences of vectors in X and Y (containing any eventually null sequence in X or Y ). A sequence of operators (un) ∈ L(X, Y ) is called a multiplier sequence from E(X) to F(Y ) if there exists a constant C > 0 such that ° °(ujxj ) n j=1 ° ° F (Y ) ≤ C ° °(xj ) n j=1 ° ° E(X) for all finite families x1, . . . , xn in X. The set of all of multiplier sequences is denoted by (E(X), F(Y )). For the study of such multipliers for the cases of E(X) and F(Y ) corresponding to vector-valued Hardy spaces, vector-valued Bergman spaces, vector-valued BMOA or spaces of vector valued Bloch functions the reader is referred to [AB1, Bl1, Bl2, Bl3, Bl4].
Assessing conservation agricultural production systems (caps) for small holder farmers in rain-fed farming system in sub-saharan Africa (ssa)
(2012) Nambozo, J.; Norton, Jay B.; Okeyo, M.; Odhiambo, Judith A.; Owori, M.; Oluko, Patrick Samba; Ogonga, P.
The challenge of sufficient food production by farmers in rainfed farming systems of sub-Saharan Africa is exacerbated by soil degradation and poor soil nutrient status. The objective of this study was to assess the effects of reduced and no tillage and velvet bean (Mucuna pruriens) cover crop on greenhouse gas (GHG) emissions and noxious weed population in alternative cropping practices to maize-bean production. Using a completely randomized block design, four replications of three tillage intensities and three cropping practices were established on two climatically different sites: Tranz-Nzoia in western Kenya, and Tororo in western Kenya and eastern Uganda, respectively. While CO2 emissions are comparable among sites and tillage treatments, N2O had significantly higher emissions in low elevation sites (where there are two growing seasons) and CH4 assimilation declined under reduced and no-tillage at high elevation sites. Reduced tilling also had a lower presence of narrow leaf species of weeds than deep tillage, but shallow hoeing had a lower weed density than no-till methods.

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