Thesis and Dissertation

Permanent URI for this collection

https://repository.nrf.go.ke/handle/123456789/1450

Browse

Now showing 1 - 20 of 25

ACOUSTIC ANALYSIS OF EKEGUSII VOWELS AND STOPS
(2020-10) OTIENO NYANSERA PETER
Preceding a theoretical exploration of issues in a language is a basic research. Through such basic descriptive study, the vitality of the language is aided and documented. This is vital especially for the less studied languages such as EkeGusii that has not been phonetically studied and documented especially using scientific methods. Following Peterson and Barney (1952), this work is an acoustic study of the vowels and voiceless stops of Ekegusii. Its goal is to transcend the impressionistic descriptions previously in the 1960s by Whiteley (1965) and Guthrie (1967). Specifically, the work explores the seven vowels of Ekegusii /i e ɛ a ɔ o u/ along with the intervening voiceless stops /p t k/ within the Source-Filter Theory of sound production. The purpose of this study is to give a complete description of the vowels and stops and document them for reference by various fields from linguistics to machine translation. The scope of impressionistic phonetics is limited by capabilities of human senses and is not verifiable while experimental phonetics like this present study extends and backs-up impressionistic description. The main objective of this study is to give a complete description of the acoustic qualities of the vowels and stop consonants from the oral data got from a purposively selected sample of twelve (four males, four females and four children), bearing in mind their speech mannerisms, geographical and dialectal considerations. Audio data was recorded as the informants read out word lists and carrier phrases bearing target sounds into a microphone connected to a computer running on Praat sampled at 44100 Hz. Analysis of audio data is primarily done using Praat software. Further, quantitative data analyses were done using MS-Excel spread sheets and SPSS with the results presented in tables, charts and written descriptions for each sound, each subject and group. The study mainly found out that EkeGusii adopts a seven vowel system with length contrast making the vowels to be phonologically fourteen. The vowels also display age, sex and dialectal variations. Results for stop consonants show that stops can be discriminated by features such as voice-onset-time, burst intensity and stop duration. Significantly, the research findings provide useful basis for codification and documentation of EkeGusii phonetics for the two dialects.
AN ASSESSMENT OF THE RELATIONSHIP BETWEEN HEAD TEACHERS’ LEADERSHIP STYLES AND PUPILS’ ACADEMIC PERFORMANCE IN PUBLIC PRIMARY SCHOOLS IN MALINDI SUB-COUNTY, KENYA
(2016-11) FREDER MWALUNGO KATUNDA
This study aimed at investigating the relationship between head teachers’ leadership styles on pupils’ academic performance in public primary schools in Malindi Sub County, Kenya. More often than not, head teachers find themselves on the receiving end of poor performance in public primary schools. Most parents tend to attribute poor performance of their children to head teacher’s leadership styles. The objectives of the study were to: find out the relationship between democratic leadership style and pupils’ academic performance; determine relationship between the autocratic leadership style and pupils’ academic performance; find out the relationship between the transformative leadership styles and pupils’ academic performance; and determine the leadership the relationship between the transactional leadership styles and pupils’ academic performance. This study was based on Fiedler’s contingency theory and rationale theory of performance. quantitative methods were used in this study. The study adopted the correlational research design that sought to measure the relationship between the variables. The study targeted a population of 750 teachers and head teachers from 30 public primary schools in Malindi Sub County. The sample was 200 participants consisting of 192 teachers and 8 head teachers. The sample was obtained through stratified sampling to establish the number of head teachers and teachers to include in the study sample. Simple random sampling was used to select 8 head teachers from 30 schools and 192 teachers from 720 teachers. Questionnaires were used; one for teachers and another for head teachers to collect data. Pilot study was carried out in two neighbouring schools which were not included in the study. The validity of the instruments was ascertained by the supervisor and two other lecturers who gave verdict on their appropriateness. The reliability was verified by using the test retest method whereby Pearson Product Moment correlation was 0.75. To cover ethical issues, clearance was done with Mount Kenya University and a permit was obtained from NACOSTI and official letters from the County Director of Education and the District Education Officer. The participants signed informed consent forms and were assured of their privacy and confidentiality. The data was analyzed quantitatively using both descriptive and inferential statistics. The findings established that independent variables had positive and significant relationship with pupils’ academic performance since the estimated Pearson Linear correlation coefficient statistic was significant at the 99% level for all the variables (Sig.<.01, r>.9). All the null hypotheses filed to be accepted. The study concludes that from the three tests on a hypothesis that is correlation, regression and coefficient, all indicates rejection of the null hypothesis paving a way for alternative hypothesis. The study recommends that head teachers ought to be given refresher courses on appropriate leadership styles to be applied in their institutions. The ministry of education should allow teachers to teach in one school for at most 10 years so as to gain experience before transferring to another school. Quality assurance officers needed to be visiting schools regularly to establish level of performance and offer necessary intervention where things are not in order. The study findings are expected to provide useful information to head teachers in helping them to re-examine and appraise their own leadership styles and hence make adjustment where necessary.
ASSESSMENT OF THE PHARMACEUTICAL MANUFACTURING INDUSTRY IN KENYA TO FORECAST LOCAL PRODUCTION SUFFICIENCY
(2017-10) SARAH KADESA VUGIGI
The World Health Organization’s global strategy on public health aims to support Member States to improve access to essential medicines. The desire of Kenya Government to implement this is expressed by formulation of Kenya National Pharmaceutical Policy (2010) which encourages local production of essential medicines for self-sufficiency. The pharmaceutical manufacturing industry in Kenya is engaged in production of various types of dosage forms but its capacity and capability to produce essential medicines for Kenyans have not been determined. The aim of this study was to assess the pharmaceutical manufacturing industry in Kenya to forecast local production sufficiency. This was attained by evaluating the manufacturing capability, production capacities and compliance with international marketing authorization standard of the Kenyan pharmaceutical industry. The 24 licensed manufacturers of medicines for human use were assessed. Data was collected on the current drug situation in Kenya by scanning Pharmacy and Poisons Board database to determine range of products that are registered in Kenya. Local pharmaceutical manufacturer’s product lists, Kenya Essential Medicines list and pharmaceutical tender lists of three major procurers in Kenya (Kenya Medical Supplies Authority, Kenyatta National Hospital and Mission for Essential Drugs and Supplies) were examined to establish the proportion of products which was manufactured locally. Prices competitiveness and market share of local products were evaluated and subsequently, pharmaceutical equivalents of 150 locally manufactured essential medicines were determined. Data on production capacity for 5 years (2010-2014) and compliance of facilities with good manufacturing practices standard and other prerequisites of marketing authorization was obtained using a structured questionnaire. Results showed that solid dosage forms were majority (54.9 %) of local products and sterile preparations were minority (2.7 %). Locally manufactured products accounted for 14.5 % of registered and 21.5 % of retained products. Local firms manufactured 38.4 % of products listed as essential medicines and 55.6 %, 24.5 % and 21.8 %, respectively, of pharmaceutical products procured by Kenya Medical Supplies Authority, Kenyatta National Hospital and Mission for Essential Drugs and Supplies. The overall percentage of local pharmaceutical equivalents was 32.5 % for registered products. There was no variation between mean prices of local and imported pharmaceutical equivalents. Scatter diagrams demonstrated that imported pharmaceutical products comprised both low and highly priced brands. The overall utilized production capacity (two shifts) was 21.5 %; tablets (24.1 %), capsules (12.8 %), liquids (25.3 %), dry syrups (21.8 %), external preparations (21.3 %) and oral rehydration salts (23.6 %). This study projected the year for self-sufficiency in non-sterile medicines produced in the local industry as 2043. Good manufacturing practices standard was satisfactory at 11 facilities while the rest were striving to achieve compliance. Research and development of new products was limited in most facilities with 1 % of the workforce deployed in this department. It is concluded from this study that Kenya depends heavily on imported drugs for her essential medicines needs. Majority of local products were less competitive than imported products and production capacity was underutilized. Majority of manufacturers adhered to current good manufacturing practice standards but were inadequate in research. This study recommends augmentation of research and development by the local pharmaceutical industry to generate new products. In addition, substantial government support is required to propel the industry to improve product range, product competitiveness and production capacity utilization.
BIOEFFICACY OF ORGANIC EXTRACTS OF FISH POISON BUSH (GNIDIA GLAUCA, FRESEN) AGAINST COWPEA WEAVIL (CALLOSOBRUCHUS MACULATUS, FABRICIUS)
(2018-11) WILHELMY MARION JEBET
Cowpea weevil (Callosobruchus maculatus) is a major pests of stored cowpea in the tropical region of the world. In Kenya, the damage caused by C. maculatus impacts negatively on its economic and nutritional values and contributes to food insecurity. The widely adopted use of chemical pesticides is marred with health and environmental hazards. Global concern on synthetic chemicals has led to heightened restrictions and limitations on their use. This, therefore, has prompted the search for alternatives to synthetic pesticides. New studies are focusing on the use of botanicals as a novel approach to the management of pests. Gnidia glauca has been exploited by local people in control of post-harvest pests. However, no scientific research has been undertaken to evaluate its potential anti-insect properties. In this study, four organic leaf extracts of G. glauca (methanol, ethyl acetate, DCM and blend) were evaluated for contact toxicity, oviposition deterrence, inhibition of progeny emergence and repellency against cowpea weevil. The plant leaves were collected from Embu County, Kenya. The samples were prepared, extracted and investigation carried out under ambient laboratory conditions. The experimental design entailed five test concentrations (2g/100ml, 4g/100m, 6g/100ml, 8g/100ml, and 10g/100ml) of each extract, the untreated control, the solvent control and the positive control-Actellic. Each bioassay had four replications. Adult weevils (1-3 days old) were exposed to the extracts and mortality was monitored daily for the first four days. Subsequently, oviposition deterrence was assessed on the 15th day while inhibition of progeny emergence was evaluated on the 49th-day post-treatment. Extract repellency was assessed for the first 6 hours after treatment. Screening for plants phytochemicals was conducted using the standard recommended procedures. The results of this study revealed all G. glauca extracts, to a varied extent, induced mortality on C. maculatus. Mortality was concentration and exposure time dependent. Highest mortality of 89.74% was recorded with 10g/100ml ethyl acetate extract 96 hours post-treatment. The extracts significantly deterred oviposition with the 10g/100ml concentration of ethyl acetate, DCMand blend statistically (p>0.05) comparable to the activity of synthetic pesticide. All the extracts were found effective in inhibition of progeny emergence. Ethyl acetate extract at the test dose of 10g/100ml demonstrated the highest inhibition of 99.3% while the least inhibition of 9.03% was exhibited by 2g/100ml methanol extract. G. glauca extracts proved to be attractant of C. maculatus rather than repellant, none of the extract concentration attained repellency greater than 50%. Results also showed that the extracts had tannins, phenols, flavonoids, terpenoids, saponins, alkaloids, cardiac glycosides and steroids which have been associated with insect control properties. It was therefore concluded that the plant extracts, possess bioactivities against Callosobruchus maculatus on the tested parameters of contact toxicity, oviposition deterrence, inhibition of progeny emergence and repellency. Hence the studied extracts can further be purified and developed into the plant-derived bio-pesticides to control C. maculatus.
CHILD EXPOSURE TO LEAD IN THE VICINITIES OF INFORMAL USED LEAD-ACID BATTERY RECYCLING OPERATIONS IN SLUMS, KENYA
(2016-11) MAUREEN AUMA ONDAYO
Leadexposure frominformal used lead-acidbattery (ULAB) recyclingoperations is a seriousenvironmental healthconcern. Researchshows that youngchildrenliving inthe vicinitiesoftheseoperationshaveelevatedbloodleadlevelsandfatalitieshavealsobeen reported. FromJanuary2015 toAugust 2015, thestudy investigatedchildexposure to lead inthevicinitiesof informalULABrecyclingoperations inNairobi slums,Kenya. This was in consideration of activity patterns of children under seven years that influencedexposurelevelsthroughhousedustandsoil.Topsoil (N=232)andfloordust (N=322)sampleswerecollectedfromdwellingunits(N=120)andpreparatoryschools (N:44)andanalyzedusing inductivelycoupledplasma-optical emissionspectrometer (ICP-OES) at theMines aridGeological Department Laboratory in theMinistryof Mining,Nairobi.Fromthe lead levels insoil andhousedustobtained,childblood lead levelswere subsequently predictedusing the IntegratedExposureUptakeBiokinetic Model forLead inChildren(IEUBK),Windowsversion.Results indicatedhigh indoor andoutdoor lead contamination instudied areas. Lead loadings inall the floor dust samples (100%) fromDandota, Kariobangi andMukuruslums exceeded theUSEPA guidancevaluefor leadonfloorswitharangeof65.2-58,l94ug/ft2.Control floordust samples recorded lower lead loadingsas compared to thevalues recorded inDandora, Kariobangi andMukuruslums. 70.7%ofthesoil samplescollectedfromwastedumps, industrial sites, residential areas, playgrounds and preparatory schools in Dandora, Kariobangi andMukururecorded leadconcentrations that exceeded the respectiveUS EPAguidancevalues for lead insoils. Leadconcentration inall (100%of) thecontrol soil sampleswerebelowtherespectiveUSEPAguidancevalues. Fromthe IEUBKwin predictions,nearly99.9%ofchildren<7yearsoldlivingnear informalULABrecycling operations inDandora, Kariobangi andMukuru slums, were at riskof being lead poisonedwithpredictedbloodleadlevelsabovetheCDCreferencevalueforbloodlead. 99.9%ofexposedchildrenlivinginDandora,KariobangiandMukumslumsarelikelyto havebloodlead levelsabove20kg/dL, 19kg/dLand34kg/dLrespectively.Thestudy establishedthatDandora,Kariobangi andMukuruslums facevastenvironmentalhealth challenges,withmanychildrenat riskofleadpoisoningduetotherapidunprecedented growthof informalULABrecycling. Thesoil andhousedust results demonstrate the need for coordinatedefforts towards decreasing leademissions frominformal battery recycling inNairobi slumsand to remediateexisting soilsparticularlyaroundbattery workplaces and dumpsites. Childblood lead levels should be clinically tested and appropriateinterventionmeasurestaken.
DERIVATION OF CYCLE INDEX FORMULAS OF SEMIDIRECT PRODUCT GROUPS
(2019-12) Muthoka Geoffrey Ngovi
The concept of the cycle index formulas of a permutation group was discovered in the year 1937. Since then cycle index formulas of several groups have been studied by different scholars. For instance the cycle index of the dihedral group Dn acting on the set of vertices of a regular n−gon is known and has been applied in enumeration of different mathematical structures. In this study the relationship between the cycle index formula of a semidirect product group and the cycle index formulas of the two subgroups which the group is a semidirect product of was established. In particular the cycle index formula of the dihedral group Dn of order 2n is expressed in terms of the cycle index formula of a cyclic group of order two C2 and the cycle index formula of the cyclic group of order n, Cn; the cycle index formula of the symmetric group Sn is expressed in terms of the cycle index formula of the alternating group An and the cycle index formula of a group generated by a cycle of length two, h(ab)i. The cycle index formula of an affine(p) group has been derived by considering the different cycle types of elements of the group and expressed in terms of the cycle index formula of Cp = {x + b, where b ∈ Zp} and the cycle index formula of Cp−1 = {ax, where 0 6= a ∈ Zp}. We further extend this to affine(q) where q is a power of a prime p and to the affine square(p) and affine square(q) groups. Finally, the cycle index formula of a Frobenius group is expressed in terms of the cycle index formula of the Frobenius complement H and the cycle index formula of the Frobenius kernel M. The cycle index formulas which are known such as that of the dihedral group and the symmetric group were used and the groups whose cycle index formulas are not known such as the affine(p), affine square(p), affine(q) and affine square(q) group were first derived as part of the research. It was noted that for semidirect groups which are Frobenius such as the dihedral group Dn with an odd value of n, the affine groups and the affine square groups, we can fully express the cycle index of the group in terms of the cycle index formulas of the subgroups which the group is a semidirect of. However, for semidirect product groups which are not Frobenius such as the dihedral group Dn with an even value of n and the symmetric group Sn, the cycle index formula of the group cannot be expressed fully in terms of the cycle index formulas of the subgroups the group is a semidirect product of.
DETERMINATION OF FECAL CONTAMINATION STATUS OF SHALLOW WELLS IN DEDE DIVISION, MIGORI COUNTY, KENYA
(2018-12) OLUOCH EVANCE ODIWUOR
A shallow well is a hole dug, bored or drilled less than 50M deep to extract water. Contamination of shallow wells with fecal matter presents a grave public health threat in developing countries, such as Kenya, where large numbers of households lack access to clean and safe water supplies and rely on untreated surface water sources or shallow unprotected groundwater for domestic utilization. A report by WHO shows that 1 billion people practice open defecation with nine out of ten of them in rural areas and it is estimated that 1.8 billion people use a source of drinking water that is fecally contaminated. In Kenya unsafe water, sanitation and hygiene are the 2nd leading risk factors causing morbidity and mortality at the national and county levels respectively. In Dede Division, 65.5% of households depend on shallow wells for domestic needs and there are rising trends of confirmed cases of fecal-related diseases. The study sought to assess human and technical determinants of fecal contamination status of shallow wells in Dede Division. A cross-sectional study of households using the wells was conducted. Fisher’s formula was then used to calculate the sample size of the heads of households. Since the approximated number of households using shallow wells was <10,000 (4008), the two stages of the formula were adopted, giving a sample size of 386 heads of households. Out of the 180 shallow wells, 54 (30% of 180) were proportionately sampled and grab sampling technique adopted while sampling water from each of the sampled shallow wells. Basic physical parameters like temperature, turbidity and pH were analysed by a portable turbidity meter and pH meter while H2S rapid field test was employed for total corliforms analysis of grab samples in the field. Fecal contamination status of each well was determined by Membrane Filter Technique in kisumu government labaratory. Chi-square test was used to measure associations between variables while Multi-variate logistic regression analysis applied to test the hypotheses. The study reported significant relationship between level of knowledge of respondents on a well being too close to a latrine as a potential route (risk factor), a well located downhill a latrine, an open/uncovered well, surface run-offs into wells, dropping objects in shallow wells, using a dirty drawer, people/animals dropping in wells, doing laundry next to a well, and human/animal feces dropping in the well as potential routes of fecal contamination. It further revealed significant associations between several technical determinants and fecal contamination status of shallow wells e.g distance (M) from a latrine to a well, with majority of wells within safe distances of contamination (>10M) but still tested positive for fecal corliforms, distance (M) from the nearest cattle pen if any with a significant majority of shallow wells testing positive for fecal corliforms, damage or lack of concrete plinth, breaks/cracks on the parapet walls, breaks/cracks in the cover/top slab, breaks in the drainage channels, shallow well covered while not in use and shallow well fenced out respectively. Majority of shallow wells (69%) tested positive for E. Coli, a strong indicator for presence of fecal matter in water, with only 31% testing negative. Common human and technical determinants (risk factors) by and large are functions of fecal contamination status of shallow wells in Dede Division. Efficient protection of shallow wells is a critical pointer to their ground water quality. Households in Dede Division should ensure adequate treatment of shallow wells for fecal contamination before utilization of water from these sources. This can be both at source or household level. They should be sensitized by the relevant authorities on common routes of fecal contamination of shallow well water and safe hygiene and sanitation practices around shallow wells to prevent fecal contamination of the wells. Households using shallow wells in Dede Division should ensure proper sighting and location of latrines in relation to shallow wells to avoid fecal contamination of the wells through leaching. The pit latrines should be sighted down hill the shallow wells and located atleast 10 meters apart.
EFFECTIVENESS OF DIFFERENTIATED INSTRUCTION IN ENHANCING STUDENTS’ ACADEMIC ACHIEVEMENTS, SELF-CONCEPT OF ABILITY AND MOTIVATION TOWARDS LEARNING OF CHEMISTRY IN SECONDARY SCHOOLS IN MAARA SUB-COUNTY, KENYA
(2016-11) ROSE GATUNE MUGWIRIA
Students perform poorly in Kenya Certificates of Secondary Education Chemistry examinations in Kenya. Chemistry is important for understanding composition, properties and behavior changes of matter that form the environment. The teaching of Chemistry aims at developing scientific attitudes, concept, principles and skills in learners. Differentiating instruction means tailoring instruction to meet individual needs of learners. Differentiating instruction consists of efforts of teachers to respond to the variance among learners in the classroom. This study investigated the effectiveness of differentiated instruction in enhancing students‟ academic achievements, self-concept of ability and motivation towards learning of chemistry. The study was guided by Howard Gadner Theory of multiple Intelligence. Quasi experimental research design was employed and in particular Solomon‟s four group design was used. The research was carried out in Four Day co-educational secondary schools in Maara sub-county, Kenya. The target population was 12,187 chemistry students. The accessible population was 1,242 form two chemistry students in Day co educational secondary schools. A purposive sampling technique was used to draw the participating schools. Simple random sampling was used to select and to assign participating schools in Experimental and Control groups. The sample size was 165 form two chemistry students. The research instruments used were Chemistry Achievement Test, Students‟ Self Concept of Ability Questionnaire and Students‟ Motivation Questionnaire. The instruments were piloted to determine their reliability, while validity of the instrument was ascertained by experts‟ opinions from Department of Education and Resource Development of Chuka University. Reliability coefficient for CAT, SSCAQ and SMQ was 0.74, 0.80 and 0.77 respectively. The experimental groups (E1 and E2) were taught using differentiated instruction teaching approach while the control groups (C1 and C2) were taught through conventional teaching approach. Statistical Package for Social Sciences (SPSS) version 21 was used for data analysis. The raw data obtained was analyzed using descriptive statistics (Mean, Standard deviation, percentages) and inferential statistics (One-way ANOVA, ANCOVA and t-test). The level of significance for acceptance or rejection of null hypotheses was at α = 0.05. The findings of the study indicated that differentiated instruction significantly improved the students‟ achievement, self concept of ability and motivation towards learning chemistry. It was also found out that when students were taught using differentiated instruction, gender did not affect their achievement in chemistry. The findings are expected to form a frame of reference for further research on innovative teaching strategies in chemistry education as well as in science education in general.
ELECTRON IMPACT ELASTIC SCATTERING OF STRONTIUM USING DISTORTED WAVE METHOD
(2018-11) KIMANI MARTIN KIRUGU
Differential and integral cross sections for electron-atom are useful for interpretation and understanding of electron contact with the targets and for determining dynamics of the collision processes. They are useful in X-ray photoelectron spectroscopy (XPS), upper atmosphere dynamics, Monte-Carlo simulation (MCS), Auger-electron spectroscopy (AES), in gaseous-exchange, laser development, plasma physics and fluorescent lighting. For elastic scattering of strontium very few calculations have been performed and currently there are no known results using the present method. Also the available theoretical results do not have other results to be compared with so it makes it important to obtain results to compare them and to be compared with future experimental results. In calculation of differential and integral cross section for elastic scattering of electron by strontium atom, first-order distorted wave born approximation method has been used to determine DCS and ICS at impact energies of 10eV to 200eV and scattering angles ranging from 00 to 1800 . Also in this study at the initial state, both initial and final channel distortion potential of elastic scattering of electron by a strontium atom are taken as the static potentials since it is an elastic scattering. The distorted waves are expanded in terms of radial wavefunctions and spherical harmonics, Numerov method was then used to solve the radial equations to obtain the radial wavefunctions. The Madison and Bartschat computer program DWBA1 for e- - H scattering was modified to perform the mathematical computations for e - - Sr scattering and the results for differential and integral cross sections are calculated and compared with the available results. The integral cross sections (ICS) results agree well qualitatively with the other theoretical results. At lower incident energies (10-30 eV), the present differential cross section (DCS) results disagree with results obtained from optical potential method. This is because the first order distorted wave method gives poor results at low impact energies and also the nature of the distortion potential used. At intermediate and higher energies (60-200 eV), the present DCS results agree well with the results obtained from optical potential method. In conclusion, the DWBA was developed and applied to 𝑒− - Sr scattering, changes on the DWBA1 computer program were made for strontium, differential cross section (DCS) and integral cross section (ICS) at impact energies 10-200eV for elastic scattering of electron-strontium were determined using DWBA at intermediate and high energies and the results compared with the other available results. From this work it was recommended that some experimental studies on electron impact elastic scattering of strontium should be made to give results for comparison with the calculated results, more theoretical studies using other methods should be conducted on DCS and ICS for purposes of comparison with the present results, a distortion potential that incorporates the polarization potential, exchange potential and absorption potential should be used in the calculation and the present method incorporating all the distortion potentials should be extended further for electron impact elastic scattering of other alkaline earth metals such as beryllium, cesium, ytterbium, and radium.
EVALUATION OF PERFORMANCE APPRAISAL TOOL ON EMPLOYEE PERFORMANCE IN KENYA COMMERCIAL BANK, NAIROBI COUNTY
(2017-06) LEAH NJERI NYAMU
Performance appraisals improve the work performance of employees by helping them realize their full potentials in carrying out their firm's mission and also, to provide information to employees and managers for use in making work-related decisions. They provide feedback to employees; determine training and development needs, numbers to be promoted as well as the levels of motivation. Performance appraisals, however, are beset with difficulties as a result of their complex nature. The general objective of the study therefore, was to evaluate the performance appraisal tool on employees‟ performance in Kenya Commercial Bank. The research design used in the study was descriptive research design because it was appropriate for the achievement of the research objectives. The population for the study was 355 and a sample size of 107 was selected using cluster sampling method to group the target population according job titles. The study applied purposive sampling to select Nairobi County because of easy of accessibility. Questionnaires were used as instruments for the study and 107 questionnaires were distributed to the members of staff and subordinate as the respondents. The data was analyzed using descriptive analysis. Organized data was interpreted on account of concurrence and standard deviation to objectives using a computer package SPSS version 21. The researcher in addition used correlation analysis and a multiple regression analysis to determine the relationship between dependent and independent variables and their level of significance. The research was based on Attribution Theory, Implicit Theory, Equity Theory and Expectancy Theory. The information obtained from this study provided commercial bank Human Resource Managers and decision makers with better insights into employee performance appraisal programs that could be used to improve employee performance.
Extraction and Characterization of Gelatin from Lates niloticus Scales and Potential Industrial Applications
(2016-07-31) CHEBON SAMMY KIPLAGAT
This study sought to extract and characterize gelatin from Lates niloticus (Nile perch) scales, then blend it with polyvinyl alcohol (PVA). Hydrolysis of the scales was done using a crude alkaline protease harvested from a bacterium, Bacillus cereus strain wwcp 1, obtained from Lake Bogoria and the resulting solution lyophilized to obtain gelatin powder. The yield was calculated based on the dry weight of the scales and was shown to be 16.3%. The sample was characterized using infrared spectroscopy and showed peaks at 3442 cm-1, 1653 cm-1 and ~ 1590 cm-1 corresponding to Amide A, Amide I and Amide II bands respectively. Amino acid analysis of the sample was done using an Agilent 1260 HPLC. Glycine was the most abundant amino acid (21.7%), followed by proline (14.6%) and alanine (11.8%). Isoleucine, Histidine and Tyrosine were the least abundant (1.8, 1.4 and 0.9% respectively). Polyvinyl alcohol-gelatin blend films of various compositions ranging from 10% to 90% PVA were prepared by solution casting method, Differential Scanning Calorimetry (DSC) and Thermo-gravimetric Analysis (TGA) tests showed the films had glass transition, melting and thermal decomposition onset temperatures intermediate between those of the respective individual polymers ( PVA and gelatin). The thermal stability of the films reduced with the increase in the amount of the less thermally stable constituent. Lastly, potential applications of the prepared blend films were investigated. Batch experiments to assess the potential of the polymer blend films as adsorbent material were done using Methylene Blue dye. The films were found to adsorb up to 64% of the dye. The percent dye removal varied with initial concentration of the dye and contact time
FACTORS INFLUENCING ADHERENCE TO ANTIRETROVIRAL THERAPY IN EMBU TEACHING AND REFERRAL HOSPITAL, EMBU COUNTY, KENYA
(2017-03) EVANGELINE KANANU NJUE MUGOH
Adherence to antiretroviral therapy is a major predictor of the survival of individuals living with HIV/AIDS. Appropriate use of antiretrovirals (ARV’s) has improved the health of many human immunodeficiency virus (HIV) positive individuals. The effectiveness of HIV treatment depends on sustenance of high levels of adherence to ARV; however, ARV regimens are often complicated and can be affected by varying dosing schedules, failing to have proper dietary requirements and patients developing adverse effects. The main objective of this study was to determine factors influencing adherence to Anti-retroviral drugs among HIV and AIDS patients 18 years and above in Embu Teaching and Referral Hospital comprehensive care clinic. A cross sectional study was carried out at EmbuTeaching and Referral Hospital in EmbuCounty, Kenya. Stratified random sampling was used to obtain relative proportion of male and female adult respondents in the sample population. Three hundred and thirty one HIV positive patients were chosen from a total of 1694 patients who were active in ART for more than one year. A semi-structured interview schedules was used to obtain demographic information and patients view on various dimension or ART services at the facility. The study revealed thatalmost half (48.2%) of the respondents had optimal adherence to ART treatment while 51.8% had sub-optimal adherence to ART treatment. Over a third (34.9%) of the patients indicated that travelling was the main cause of hindrance to optimal adherence to treatment. Other reasons included forgetfulness 23.5%, tiredness of taking drugs all the time 20.8% and side effects 20.8%. Patients aged below 25 years were more likely to have optimal ART adherence as compared to respondents aged 56 years and above (ᵡ 2 =10.745, df=4, pvalue = .030). Monogamously married and polygamous married patients more likely to have optimal adherence as compared to widowed or widower respondents (ᵡ 2 =17.944, df=4, p-value = .001). Majority (88.0%) of the respondents had disclosed their HIV status to other people of whom 46.9% had disclosed to their spouse/sexual partner and 49.7% of them had been accorded moral support. There was significant association between adherence to ART and the type of drug respondent was using with AZT, ddl, NFV having the highest proportion of sub-optimal adherence to treatment while respondents on D4T, 3TC, NVP had the lowest proportion of suboptimal adherence to treatment. Patients who had sub-optimal ART adherence significantly had longer waiting time and deemed costs of co-infection treatment to be higher as compared to respondents who had optimal ART adherence. Convenience of the facilities for people with chronic ailments and waiting time at the facilities were reported to be lower. The study concludes that majoritypatients had sub-optimal adherence to ART treatment. Adherence was significantly influenced by age; marital status; engagement in income generating activity;type of drug takenand costof coinfection treatment;health facility accessibility and perceived waiting time.The study recommends that HIV patients should be sensitized on importance of carrying ART drugs when travelling and the use of treatment assistants to ensure optimal adherence thus enabling them fully realize its life extending benefits as it has been shown that there is significant non-adherence among HIV positive patients on ART in the County.
FACTORS INFLUENCING ENROLMENT AND RETENTION OF STUDENTS IN PHYSICS IN SECONDARY SCHOOLS IN IMENTI SOUTH SUB-COUNTY KENYA
(2016) KAIRO NKIROTE CATHERINE
Despite the place of physics in science, technology and national development, the number of students taking physics as their choice in secondary schools is declining. The purpose of this study was to investigate factors influencing enrolment and retention of students in physics classes in secondary schools in Imenti South Sub-County of Meru County. The study was based on achievement motivation theory. The study adopted descriptive survey research design. The target population was 14,097 subjects comprising of 13,943 students and 154 physics teachers in secondary schools in Imenti South Sub-County. Simple random sampling technique was adopted to select students and physics teachers from the population in Imenti south Sub-county. The sample size was 364 respondents comprising of 356 students and 8 physics teachers. Data was collected by use of three questionnaires, for the form two students, form three students and the other for the physics teachers. Piloting was carried out in two secondary schools in the neighbouring Imenti North Sub-county where 42 students and 4 physics teachers participated. Spearman Brown formulae was used to estimate the reliability co-efficient of the instruments. The reliability coefficient of 0.851 and 0.957 for students and teachers questionnaire respectively was obtained. The research instruments were validated with the help of supervisors. The data collected was cleaned, coded and entered into the computer for analysis. Statistical Package for Social Science version18 was used for data analysis. The data was analyzed using descriptive statistics and the findings presented using tables, graphs and charts. The study established factors influencing enrolment and retention in physics include; lack of adequate teaching and learning apparatus, poor performance in physics, teaching methods used in practical lessons, playing with electrical gadget and making models during early childhood, naming constants and principles after male scientists. The research findings will provide important information to policy makers and other stake holders in the Ministry of Education on the influence of available teaching and learning physics resources in schools in regard to enrolment and choice of physics. The study will provide information to physics teachers on the influence of the methodologies used in teaching physics on selection of physics by the students. This may help physics teachers to know which intervention measures to take while teaching in order to improve student’s enrolment in physics. The study is of significance to the students because it enlightens them on the importance and the benefits of studying physics. The study also will sensitize the parents on the importance of physics and their role in exposing children to experiences that demonstrate physics knowledge during childhood. This will help in improving enrolment and retention of students in physics in secondary schools.
FREQUENCY OF SULFADOXINE PYRIMETHAMINE RESISTANCE ASSOCIATED GENE MUTATIONS IN PLASMODIUM FALCIPARUM CLINICAL ISOLATES FROM KWALE COUNTY, KENYA
(2020-01) WINFRED KENDI MUTWIRI
Malaria persists to be one of the world’s complex and dynamic disease. The disease is more devastating in sub-Saharan Africa as it constitutes high cases of childhood mortality and morbidity. Management of the disease remains a problem as a result of the spread of parasites that are resistant to the available drugs. Due to the broadened spread of resistance to Sulfadoxine Pyrimethamine (SP), the artemether-lumefantrine which is a more effective and well-tolerated anti-malarial drug replaced the SP as the first-line regimen in treatment of uncomplicated malaria in Kenya. However, SP remains the suggested drug to treat and prevent malaria in expectant women and children under the age of five. This study sought to assess the presence of mutation in dihydrofolate reductase and dihydropteroate synthase genes associated with SP resistance a decade after Sulfadoxine-Pyrimethamine was withdrawn as the first-line anti-malarial drug of choice in Kenya. Smear-positive samples (N = 134) collected from a 2013 cross-sectional study in infants managed at Msambweni District Hospital were evaluated for mutations in dhfr and dhps (SP).The findings obtained were matched up with molecular data from infants in Western Kenya in a study carried out in 2003/05. In all the 134 samples, mutations at codons N51I, C59R, S108N had a high predominance at 80.6%, 72.4% and 93.3% respectively. The double mutant of Pfdhps A437G/ K540E had an occurrence rate of 82.1% and 78.4% respectively. Compared to the molecular data of 2003/05 study, the Pfdhfr triple mutant (S108N/N51I/C59R) genotype decreased to 63.4% in 2013 up from 68%. However, this reduction was not significant (p=0.387). There was no significant change in the prevalence of Pfdhps double mutant (A437G/K540E) genotype (p=0.485). The percentage of isolates which had the Pfdhps A437G/K540E/ Pfdhfr N51I/C59R/S108N quintuple mutant linked with SP-resistance did not change significantly over the two study periods under consideration (53.5% in 2003/05 versus 53.7% in 2013, p = 0.967).The high prevalence of SP resistance marker in the coastal Kenya could be attributed to circulation and SP drugs being sold over the counter which has maintained a selection pressure for the mutations and fixation in the key mutations in the inhabitants. Also the mutation could have a little effect on the fitness of fit of the parasite such that withdrawal of drug pressure did not offer any survival disadvantage hence the continued spread of resistant parasites. Further investigations should be done to determine the linkage between SP drug resistance associated mutations and efficacy of IPTi-SP since the mutation levels are still high. It is also recommended that doctors using SP for IPTi and IPTp should be more cautious and their use monitored to ensure cases of poor response are managed with a different drug.
FUNCTIONALIZED GEOPOLYMERS DERIVED FROM CLAY AND RICE HUSK FOR REMOVAL OF SELECTED HEAVY METALS AND METHYLENE BLUE FROM AQUEOUS SOLUTION
(2018-10) MAINGI MUKORA FRANCIS
With the onset of industrialization, humanity has witnessed various ecological issues in the society and disturbance of ecosystem. Heavy metals and methylene blue are very toxic substances known to cause detrimental effects to human health when ingested even at low concentrations. Several techniques are available for removal of heavy metals, and dyes from the wastewater such as chemical precipitation, ion exchange, adsorption, membrane among others. Among these technologies adsorption is preferable for wastewater treatment due to its simplicity in design, high efficiency and availability of materials involved. Geopolymers are inorganic polymers and have been in use in construction industries as alternatives to ordinary portland cement but very little information is available on their use in environmental pollution management. This study aimed at synthesizing and functionalizing amorphous geopolymers from common clay and rice husk ash for use as adsorbents in removal of heavy metal ions and methylene blue from contaminated water. There is adequate literature indicating that clay minerals contain both silicates and alumina while rice husk ash contains substantial amounts of silica. This work therefore reports synthesis of geopolymers GP 1, GP-2 and GP-3 using clays and rice husk ash that were functionalized using citric acid and EDTA for use in adsorption of heavy metals and colour. Characterization of the geopolymers was done using FT-IR, EDS, XRD and SEM. Batch experiments using Pb (II), Cd (II), Zn (II) ions and methylene blue (MB) were done. FT-IR indicated presence of Al-O and Si-O bonds which are the finger prints of geopolymers. XRD analysis showed presence of amorphous phase between 18-36° (2θ) an indication that geopolymerization occurred. SEM analysis revealed the formation of a heterogeneous matrix which consists of a dense continuous gel with microcracks and voids on geopolymer adsorbents. The mean percentage uptakes of 99.32 ± 0.04, 99.74 ± 0.01, 91.33 ± 0.06 and 91.99 ± 0.57 of Pb (II), Cd (II), Zn (II) and MB were achieved respectively. Various equilibrium models were employed and from the correlation coefficients (R2 > 0.94), the data was found to fit best in Langmuir Freundlich model (Sips). The highest adsorption capacities of Pb (II), Cd (II), Zn (II) and MB were 326.5, 175.5, 169.9 and 20.74 mg/g respectively, attained using GP-3E. Increased adsorption of Pb (II), Cd (II), Zn (II) ions and MB was observed upon functionalization as well as when Si/Al ratio increased. Kinetic studies showed that a pseudo- second order model was more suitable than the first order in explaining the adsorption mechanism. This indicated that the adsorption transient behaviour used valence forces or exchangeable electrons and that chemisorption was more pronounced in the rate determining step. Thermodynamic studies revealed that the adsorption process was endothermic and physisorption since values of ∆H° obtained were < 40 kJ/mol. From the adsorption data, it‟s evident that synthesized geopolymers are potential adsorbents for removal of heavy metals and MB and may be employed in wastewater management.
MODELING THE EFFECTS OF INTERFERENCE IN FERTILITY RATE: A CASE STUDY OF RWANDA, INDONESIA AND KENYA
(2016) ODERO EVERLYNE AKOTH
Many studies have been done on fertility for many years. However, very little has been documented in the existing literature concerning modeling of fertility in the presence of interference, yet interference to fertility is a common phenomenon. In this study fertility data sets for Rwanda, Indonesia and Kenya were modeled before and after interference. The parameters of the model were estimated ted by the maximum likelihood estimation method. The model life table approach was used to determine the Net Fertility Value, Fo. A relationship between fertility rate in the presence of interference and population growth was also determined Using Akaiko's Information Criteria (AIC) population growth was also determined. Using Akaike's Information Criteria, (AIC), it was established that amongst the distributions fitted; Gamma, Weibull and Lognormal, was established that amongst the distributions fitted: Gamma. Weibull and Lognormal Gamma gave the best fit for the fertility rate data, for all the countries studied, and interference simply shifts the Gamma distribution parameters. The result of this study would help the Governments to understand fully the effect of interference on fertility rate and plan for it. Demographers would also benefit from this study since it can be used to project population growth after an interference.
Potential use of Kenyan Entomopathogenic Nematodes and Neem (Azadirachta indica) for the Sustainable Management of Tomato Leaf Miner (Tuta absoluta)
(2018-06) DAVID MUNYUA MUTEGI
The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) was reported in Kenya in 2014 and has become a devastating pest of tomato crop in both the field and in the greenhouse. The objectives of this study were; to determine the pathogenicity of Heterorhabdities species and Steinernema karii nematodes against tomato leaf miner in laboratory conditions; to evaluate the insecticidal effects of neem biopesticide against tomato leaf miner in the greenhouse and to evaluate the effectiveness of entomopathogenic nematodes and neem combined with entomopathogenic nematodes as management options for tomato leaf miner in the greenhouse conditions. Entomopathogenic nematodes (EPNs) used in the study were obtained from Kenya Agricultural and Livestock Research Organization (KALRO) entomopathogenic nematodes laboratories and Tuta absoluta larvae were obtained from a colony reared and maintained in a greenhouse at Kabete Campus Field Station, Nairobi. Multiplication of the EPNs was done by invivo method or the insect-bait technique with the third instar of greater wax moth (Galleria mellonella). Bioassays were conducted in petri dishes where the effects of EPNs concentrations; at 100, 300and 500Ijs/ml on Tuta absoluta larvae exposed for 24-72 hours were evaluated. Secondly, three different concentrations namely; 20ml/20L, 40ml/20L and 60ml/20L of Nimbecidine® (Azadirachtin) were evaluated against Tuta absoluta populations in the greenhouse. Thirdly, the following management options; Steinernema karii nematodes alone applied at a rate of 1000 Ijs/ml with oil adjuvant Addit® as a wetting agent in water, Steinernema karii nematodes and neem (Azadirachtin 0.03%) applied sequentially after one hour at a rate of 40ml/20L were evaluated against Tuta absoluta populations. These were compared with Coragen® SC (20% Chlorantraniliprole) synthetic pesticide applied at the rate of 3ml/20L and control where only water was applied. A delta sticky trap supplied with Tuta absoluta pheromone was hanged at the centre xiii of the greenhouse at a height of one metre for monitoring Tuta absoluta numbers to enable the initiation of treatments. The results obtained showed that, the evaluated concentration rates of Heterorhabditis species and Steinernema karii at 100Ijs/ml, 300 Ijs/ml and 500 Ijs/ml significantly caused (p < 0.05) mortality to the Tuta absoluta larvae and the highest mortality was recorded at 500 Ijs/ml concentrations with an exposure period of 72 hours. Steinernema karii was more pathogenic compared to Heterorhabditis species with respect to exposure time, having shown 100% and 91.5% larval mortality, respectively. Secondly, the evaluated neem concentrations 20ml/20L, 40ml/20L and 60ml/20L significantly (p < 0.05) reduced Tuta absoluta population in the greenhouse tomato. The high concentration (60ml/20L) was more effective in reducing Tuta absoluta population and fruit damage compared to the lower concentrations and control. High fruit damage of 96.2% was recorded in the control compared to 30.0%, 23.4% and 20.0% for 20ml/20L, 40ml/20L and 60ml/20L dose rates, respectively. Lastly, EPNs alone and EPNs combined with neem significantly (p < 0.05) reduced the population of Tuta absoluta. The number reduction of Tuta absolutaby EPNs combined with neem did not differ with that which was achieved in Coragen®. Tomato fruit damage was highest in the control with 91.5% compared to 10.8%, 7.9% and 3.0% for EPNs alone, EPNs combined with neem and Coragen®, respectively. This study demonstrates the potential of EPNs alone or in combination with neem applied successively at a one hour interval, as an alternative strategy for the sustainable management of Tuta absoluta in the greenhouse conditions.
PREVALENCE OF ECHINOCOCCOSIS IN DOGS, CATTLE, SHEEP AND GOATS, LEVEL OF KNOWLEDGE AND ASSOCIATED ECONOMIC LOSSES
(2018) MABEL INYANGALA GACHENGO
Cystic Echinococcosis (CE) is an emerging and re-emerging zoonotic infection caused by the larval stage of the dog tapeworm of the genus Echinococcus. It causes great public health and economic problems and remains neglected in Sub-Saharan Africa. The level of knowledge is poor in most developing countries. This study was carried out to determine the prevalence of echinococcosis and its trend, level of knowledge and associated economic losses in Laikipia West Sub-County. A total of 4969 animals (522 cattle, 3428 sheep and 1019 goats) slaughtered in abattoirs were inspected for hydatid cysts; a questionnaire was administered to one adult member from each of the 300 household using mobile data collection Kit. Faecal samples from 401dogs were used to determine prevalence of echinococcosis in dogs. Data from Veterinary office meat inspection reports 2010-2014 were used to determine trends and associated economic losses due to CE. The prevalence of CE in slaughtered animals was 8.8% in cattle, 1.7% in sheep and 1.7% in goats. Prevalence of echinococcosis in dogs was 0.5% (2/401). The level of knowledge of echinococcosis was 25% (n=300). A total of 98,495 animals were inspected during the period 2010-2014 and results showed an increasing trend with time for both prevalence and economic loss. There was evidence of CE transmission and the level of knowledge of Echinococcosis was low. The public health implications and economic losses call for concerted control efforts. More elaborate studies on echinococcosis are recommended in dogs and man.
PRODUCT DESIGN STRATEGY UTILISATION IN DETERMINING THE PERFORMANCE OF MICRO AND SMALL TEXTILE ENTERPRISES IN NAIROBI CITY COUNTY, KENYA
(2023-09) ADONIJAH OMBURA
Kenyan textile micro and small enterprises (MSEs) face a myriad of performance challenges, key being low product differentiation. This is when enterprises imitate each other's products. Scholars have recommended research into the most effective business strategies textile micro-enterprises can utilize in order to address low product differentiation. The purpose of this study was therefore to determine the utilization of product design strategies on the performance of textile MSEs in Nairobi and thereafter develop a textile MSE product design guide that will be used in improving product innovations. Focussing on Nairobi City County's CBD, the first objective set to explain the product design strategies used by MSEs in the textile sub-sector. The second objective intended to determine the number of product innovations generated by textile MSEs in the combined year’s 2016 and 2017. The third objective of the study determined how product design strategies affect textile performance. The fourth and last objective focussed on the creation of a textile MSE product design guide. This study took up a deductive, epistemological investigation that followed a pragmatic philosophy with the following theories underpinning it: the Componential Theory of Creativity (CToC); the Concept Knowledge Theory (C-K); the Resource Based View theory (RBV) and the Dynamic Capabilities Theory (DCT). Purposive and snowball sampling were used to identify the textile MSEs before surveys with descriptive and explanatory designs and quantitative data analysis were done. A chi-square goodness of fit test revealed significant variation in textile MSEs' product innovations. The test was statistically significant for the variation in the amount of product innovations by textile MSEs. A second multiple logistic regression test indicated that both benchmarking strategies and research strategies had a significant influence on innovation. Thereafter, a Pearson chi-square independence test revealed a statistically significant association between the two strategies under study and their product innovation, however, the association strength was found to be weak as indicated by a Lambda test and confirmed by Phi coefficient as well as a contingency coefficient test. The ANOVA effect size analysis test was then used to reveal that the combined strategies had medium to small effects on the dependent variable. In conclusion, the test results showed that there was a significant influence of product design strategies on the performance of textile MSEs in Nairobi City County, Kenya. In light of this, a comprehensive product design guide, specifically tailored for textile micro and small enterprises (MSEs), and to be used in improving product innovations was developed. Other recommendations from the study include: improving the work environment and intrapreneurship orientation; using combination strategies for increased performance (innovation) and using design guides like the one proposed by the study. Recognition of design management as a critical intervening variable that affects the performance of textile MSEs was also made. Due to their limitation in size of the MSEs, the study also found the need to use association and collaboration to improve performance, while diversification strategy can be effectively employed to mitigate competition and imitations. Additionally, association and collaboration with design consultative units in Research institutions, Universities, government departments, or NGOs for robust R&D and NPD was encouraged.
RISK ASSESSMENT DUE TO NATURALLY OCCURRING RADIOACTIVE MATERIALS IN KILIMAMBOGO, KENYA
(2023-12) NYAMBURA CATHERINE
Man is continually exposed to ionizing radiation whose main origin is either natural or artificial. The primordial radionuclides found in building materials are important sources of radon and thoron in the indoor air. The main objective of this research was to assess exposure due to radioactive elements in indoor air, crops and building materials (soil and rocks), and determine the level of the risks. The concentration levels of radon, thoron, and thoron progeny were measured in mud-walled, iron sheet walled, and stone walled modern houses in Kilimambogo region, Kenya. Radon and thoron concentration levels were determined using passive radon–thoron discriminative monitors (RADUET), while thoron progeny levels were measured using thoron progeny monitors. The activity concentration of 226Ra, 232Th and 40K present in the different environmental samples like rocks, soil, and cassava crop were determined using a Thallium- activated sodium-iodide scintillation (NaI (TI)) detector Model TS-2L. Elemental concentration in water samples was determined using an atomic absorption spectrophotometer (AAS). The mean external dose received indoors by the residents due to radionuclides present in rock and soil samples was measured to be 0.91 ± 0.26 mSv y-1 and 0.86 ± 0.19 mSv y-1 respectively. This is comparable to the total exposure dose limit of 1 mSv y-1 recommended by ICRP for members of the general public. This means that, soil and rocks in the region does not pose any radiological risk to the residents of Kilimambogo region. Consequently, they can be used for agriculture and construction of dwellings. The doses received due to intake of cassava tubers and leaves was 1.82 ± 0.60 mSv y-1 and 0.81± 0.30 mSv y-1 respectively, totaling to 2.63 ± 0.70 mSv y-1. The ingestion dose contributes to 42.1% of the total dose received by the resident from measured sources. Residents should therefore reduce the intake of cassava. The annual effective dose received by the residents of Kilimambogo and Gatuanyaga regions due to inhalation of radon and thoron was determined for the three types of dwellings, from their respective progenies and found to be 1.3 ± 0.2 mSv y-1, 1.1 ± 0.1 mSv y-1 and 1.4 ± 0.2 mSv y-1 for radon progeny and 2.4 ± 0.4 mSv y-1, 0.5 ± 0.1 mSv y-1 and 1.5 ± 0.2 mSv y-1 for thoron progeny in mud-walled, iron sheet-walled and stone-walled houses respectively. It was observed that, residents living in iron sheet - walled houses with cemented floors received the lowest doses from inhalation of the radon isotopes hence such houses are safer than other types of dwellings. Residents living in mud houses and uncemented houses should consider improving the ventilation of their houses to reduce radiation exposure. The lifetime cancer risks for the residents due to intake of metal carcinogens, Cd, Ni and Pb in borehole and surface water was also estimated. The cumulative cancer risk in the borehole samples was 0.12 ± 0.06 and 0.19 ± 0.09 in the dry and wet seasons respectively. Those from surface water sources were 0.10 ± 0.07 and 0.21 ± 0.06 in the dry and wet seasons respectively. In both seasons, the cancer risks were much greater than the acceptable risks of 10-6 to 10-4 by a factor of 1000 and above. This indicates that about 10% of the residents are likely to die of cancer related ailments. RESRAD computer simulation code was used to estimate the doses received by the resident farmer and the quarry worker scenarios at time, t = 0 years. The doses received by the resident farmer and quarry worker scenarios were 0.22 mSv y-1 and 0.16 mSv y-1 respectively only for the external radiation pathway. This risk is low and does not pose any significant health risk to the residents. The data measured in this research will be used by future researchers as baseline study.

Browse

Browsing Thesis and Dissertation by Title

Results Per Page

Sort Options