11230 Records out of 22207 Records

Evaluation of economic efficiency of tick control practices among smallholder dairy farmers in Kenya

Author: Okoth, Edward

Awarding University: University of Nairobi, Kenya

Level : MSc

Year: 0

Holding Libraries: International Livestock Research Institute Library ;

Subject Terms: Ticks ; Dairy industry ; East Coast Fever ; Theileria parva ; Vaccines ;

Abstract:

East Coast fever (ECF) is a highly fatal Iympho-proliferative disease of cattle caused by tick-borne protozoan Theileria parva. The intra-lymphocytic schizont stage induces a cancer-like transformation of the infected cell which is responsible for the pathology and ultimately death of infected animals. Immunity from the cattle that recover from ECF or treated using live vaccines is mediated by parasite-specific CD8+ cytotoxic T lymphocytes (CTL), which target and clear schizont-infected lymphocytes. Although the identified CTL target antigens have been evaluated using DNA and attenuated pox virus vectors and have been shown to induce CD8+ CTL responses in a proportion of cattle that have correlated with reduced disease severity upon parasite challenge, the inability to consistently trigger the protective CTL responses is a major impediment that needs to be overcome. This study?aimed at evaluating. the potential of recombinant live attenuated Listeria monocytogenes (Lm l'1actMinlB) expressing three defined T. parva CTL epitopes to stimulate protective CTL responses against T. parva in cattle upon lethal parasite challenge. In vitro studies using recombinant Lm l'1actAMnlB indicated that one of the T parva CTL epitopes could be weakly expressed and recognized by antigen-specific COW T cell lines in one of the experiments. Cattle were screened against L monocytogenes T cell target antigenic peptide pool, listeriolysin-O (LLO), and the vaccine select animals based on those with no or low background responses to LLO. Induction of epitope-specific CD8+T celllFN-y immune responses were detected in three out of nine vaccinated animals while T cell responses in PBMC to LLO were observed in eight animals immunized with either wild type or recombinant Lm l'1actAl'1inlB. Cytotoxic T cell responses were detected after boosting in only one of nine immunized animals. However these responses did not translate into a significant protective effect after challenge. This may be in part due to poor expression of recombinant antigens leading to sub-optimal induction of protective antigenspecific CD8+ T cells. Although this immunization regime failed to induce protective CD8+ T cells against T parva in all the animals. By modifying the antigen formulation, dose, mode and route of inoculation a more efficient protocol can be developed. This kind of formulation will find application in vaccine preparation in other diseases including cancer where the induction of CD8+T-cell immunity is critical.

Lime requirements of Kenya acid soils.

Author: Nuwamanga, J K

Awarding University: University of Nairobi, Kenya

Level : MSc

Year: 0

Holding Libraries: University of Nairobi Upper Kabete Library ;

Subject Terms: Soils ; Lime ;

Abstract:

ABSTRACT NOT AVAILABLE

An investigation of stone structures and earthworks in Bondo Division, Lake Victoria Basin, Kenya

Author: Odede, Fredrick Z A

Awarding University: University of Nairobi, Kenya

Level : MA

Year: 0

Holding Libraries: British Institute in Eastern Africa Library ;

Subject Terms: Bondo Division, Siaya District ; Lake Victoria Basin, Kenya ; Stone ;

Abstract:

ABSTRACT NOT AVAILABLE

The outcome of conservative management of tibial shaft fractures in Kenyatta National Hospital

Author: Oburu, G Jagero

Awarding University: University of Nairobi, Kenya

Level : MMed

Year: 0

Holding Libraries: University of Nairobi Medical Library ;

Subject Terms: Legs ; Fractures ; Bones ; Surgery ;

Abstract:

INTRODUCTION Tibial shaft fractures are the most common long bone fractures encountered all over the world, motor vehicles accident being the most common single cause. Closed reduction and cast immobilization has been regarded as the standard treatment for low energy tibial shaft fracture. This mode of treatment has proved to be generally successful and offers reliable healing without the risks seen in operative procedures. A subset of patients however have less than satisfactory outcome with this modality of treatment but literature remains ambiguous in identifying the fractures best managed operatively. MATERIALS AND METHODS A prospective study was conducted looking at the conservative management of tibial shaft fractures. Patients were recruited from casualty or in the wards and consents' were taken if they satisfied the inclusion criteria. Patients were recruited from April 2005 to December 2005 and followed up to June 2006. Patients were classified as per the dynamism of injury, severity of soft tissue damage, geographical location of the fracture, fracture geometry and Gustilo classification. The extent of alignment, angulations and limb shortening of the fracture were determined. A cast of plaster was applied and the patients were followed up over a period of six months with repeated check x-rays and re evaluation of alignment, angulations, limb length, callus formation and time to union. RESULTS One hundred and seventy patients with 178 fractures, 154 (90.6%) male and 16 (9.4%) female patients were recruited. There were 108 (60.7%) fractures followed up. Most of the injuries were sustained from RTA, 116 (65.2%) cases. There was a mean time to union of 15.85 weeks and a union range of 4 to 38 weeks. There was a rate of union by 20 weeks of81.5%. There was a non union rate of 7.4%, a mal-union rate of 17.6% and delayed union rate of 11.1 %. The infection rate was 6.6%. The fracture geometry, alignment and angulations were the main causes of complications.

A comparison of some physical characteristics of eroded sediments and surface soil on two different slopes in Githunguri, Kiambu District of Kenya.

Author: Obando, Joy Apiyo

Awarding University: University of Nairobi, Kenya

Level :

Year: 0

Holding Libraries: Kenya Soil Survey Library ; National Council for Science and Technology Library ;

Subject Terms: Comparative studies ; Soil erosion ; Sediments ; Githunguri Division, Kiambu District ;

Abstract:

Eroded sediments were collected from runoff plots on two slopes at Waruhiu Farmer's Training Centre, Githunguri, Kiambu district. Twelve experimental plots, six on 4% slope and six on the 24% slope were planted with four annual crops: maize, beans, maize and beans intercrop and Irish potatoes. In addition, two control plots, one bare and one with 100% grass cover were used on each slope. Hydrometer analyses of particle size distribution of eroded sediment as well as that of the surface soi~ at the beginning and end of the study period were carried out in both undispersed and dispersed forms. The main objectives of this study were: (i) To examine the influence of rainfall and vegetation cover on particle size distribution of the eroded sediments. (ii) To determine and compare some physical characteristics of the eroded sediments with those of the surface soil at the beginning and at the end of the study period. (iii) To determine whether the aggregate size distribution of eroded sediments changes throughout a rainfall season. Correlation analyses were performed to ex~ine the re1ation- ships between the percent fine particle sized material in the eroded sediment and each of the following variables: rainfall amount, maximum thirty minute intensity (MI30),product of rainfall and thirty minute intensity (AI30), and vegetation cover. The proportion of aggregates, organic matter content, dispersion ratios, clay ratios and flocculation indices of the eroded sediment and surface soil were determined and compared for the two slopes. The findings from this study were as follows:- 1. Sediment sizes were affected only slightly by rainfall amount and intensity factors (M1SO and AI30). The relative percent of fine par t Lc.Le sized material eroded decreased as the rainfall intensity and rainfall amount increased. 2. Sediment sizes were affected by vegetation cover. Vegetation cover was shown to be postively correlated with the fine particle sized material in the eroded sediment. An increase in cover resulted in an increase in the relative amount of percent fines eroded. The soil loss and runoff were also shown to be reduced with increasing cover on- the gentle slope (4%). 3. Much of the sediment eroded from all P~9ts (except grass) was in the form of aggregates, and som~ of these aggregates were larger in size (>50 pm) than the primary particles of which the soil was composed. In general, the eroded sediment consisted of a higher percentage of finer ?50 fm) particle sized material than the original surface soil though the differences were very small for both slopes and plots. 4.A general reduction occurred in the percentage of aggregates from the soil that resist breakdown, demonstrating a weakening of the soil structure. The dispersion ratio, clay ratio and flocculation indices of the soil indicated a reduction in the stability of the soil resulting from cultivation and losses of fine soil particles and nutrients. The relationships obtained illustrate that sediment size distribution were affected by rainfall and cover, and suggest that size distribution studies should be undertaken in the form in which sediment is eroded as well as after dispersal. Additional research would yield more meaningful results on these characteristics of sediment for different soils, slopes, rainfall factors, vegetation cover and type of tillage.

Genetic characterization of African chicken using mitochondrial DNA D-Loop sequences

Author: Mobegi, Victor Atunga

Awarding University: University of Nairobi, Kenya

Level : MSc

Year: 0

Holding Libraries: International Livestock Research Institute Library ;

Subject Terms: Poultry ; Genetics ;

Abstract:

Knowledge of the genetic diversity is a prerequisite for better utilization of any genetic resource. However, such information is lacking for the indigenous African chicken. Mitochondrial DNA (mtDNA) displacement (Dj-Ioop sequences were used to study the genetic diversity, genetic differentiation and phylogenetic relationships between domestic chicken populations and/or breeds of Africa. A total of 398 individuals belonging to 28 populations were sampled from 12 African countries. The hypervariable 1 (HV1) segment of the D-Ioop was peR amplified and subsequently sequenced. The sequences of the first 397 nucleotides were used for analysis. Fifty-two haplotypes were identified from 50 polymorphic sites with polymorphism between nucleotides 167 and 397 contributing to 96% of the sequence variations. Phylogenetic analysis of the haplotypes indicates that African domestic chicken mtDNA can be grouped into six distinct maternal lineages with one to four lineages observed in each population. One of the haplotypes (represented by Bur60) is shared by all populations except Malawi, suggesting that these populations may share the same maternal ancestor. The phylogenetic relationships between populations show a close relationship between Kenya, Malawi, and three Botswana populations (Malolwane, Semitwe and Motokwe). Genetic variations within populations and between populations accounts for 64.8 and 35.2% of the total genetic variation, respectively. Network analysis shows a star-like population structure which suggests a rapid population expansion from a small number of founding ancestors. These results show a high mitochondrial D-Ioop diversity in African chicken and indicate multiple maternal origins for African domestic chicken.

Review methods of estimating parameters in known linear mixed-effective (nlme) models

Author: Mbunzi, Stephen

Awarding University: University of Nairobi, Kenya

Level : MSc

Year: 0

Holding Libraries: International Livestock Research Institute Library ;

Subject Terms: Sheep ; Statistics ; Genetics ; Linear mixed effects ; Computer based modeling ; Nonlinear programming ;

Abstract:

This study is a critical review of theoretical issues that underline the linear mixed effects (LME) and nonlinear mixed effects (NLME) models. These two areas revisited under maximum likelihood and restricted maximum likelihood estimation frameworks. We also review methods of estimating parameters in both linear and nonlinear mixed effects models. In the case of LME, we consider different ways of developing the likelihood estimators, key among these methods are the 'pseudo-data' approach, orthogonal triangular decomposition method and use of penalized least squares problem. For NLME, we intended to investigate the computational efficiency and accuracy of computational methods, like the b-splines, that could be used to approximate the log-likehood function in non-linear mixed effects models. This was not achieved in this study but can be an interesting area for further research work. We critically review the four methods of estimating parameters by Pinheiro and Bates (1995) through proving a number of lemmas. Our proofs led us to same stated results by different researchers in different papers. This is a key issue in the investigation of other expansion methods and comparing their computational efficiency and accuracy with these existing ones. We conclude by giving an insight into linear mixed effects models by analyzing a data set from livestock where we examine incorporation of random effects to study variations among rams (sires) and ewes (dams) and their influences on lamb weaning weight. Factors like year of birth of the lamb, sex of lamb, age at weaning, age of dam, ewe breed and ram breeds. It was our intention to obtain heritability estimates which determine the proportion of the variation among offspring that have been handed down from parents out of these random estimates. Keywords: repeated-measures data, multilevel data, longitudinal data, LIME, NLME, 'pseudo-data and b-splines.

Mechanisms of sorghum resistance to the spotted stalkborer, Chilo partellus (Swinhoe) Lepidoptera Pyralidae.

Author: Masina, Greenman Themba

Awarding University: University of Nairobi, Kenya

Level : PhD

Year: 0

Holding Libraries: University of Nairobi Jomo Kenyatta Memorial Library ; International Centre of Insect Physiology and Ecology Library ;

Subject Terms: Sorghum ; Spotted stalk borer USE Chilo partellus ; Butterflies and moths ;

Abstract:

Stalkborers are some of the most important pests of cereal crops in the tropics and in particular the semi-arid areas. Chilo partellus, the spotted stalkborer, is one of the most notorious pests of sorghum in that it occurs in almost all the areas where sorghum is grown in the semi-arid regions of Asia and Africa. Lately it has been found that this pest is gradually increasing its range and importance. Of the various sorghum pest control methods available in the semi-arid regions none holds better 'prospects than the use of resistant varieties. In this study several experiments were conducted to elucidate the mechanisms of resistance of different sorghum cultivars and also to propose the methodology for mechanisms of resistance studies. Accordingly five criteria were used - for explaining these mechanisms. These criteria were : (a) Preference or Non-preference for oviposition of the moth on different sorghum cultivars, (b) Larval establishment of Chilo partellus larvae first instarL on different sorghum cultivars, (c) Relative leaf damage and stem tunnelling in different sorghum cultivars by C. partellus larvae, (d) Biophysical and prelimary biochemical studies that elucidate the differences in cultivar susceptibility to C. partellus, and (e) studies on different cultivar tolerances to C. partellus damage. The oviposition preference studies revealed that sorghum cultivars differed in their suitability as a C. partellus oviposition substrate. Cultivar IS 2205 was the least preferred while IS 18363 was the most preferred. Experiments to identify the factors responsible were inconclusive. Evidence pointed to both biochemical and biophysical factors. First instar larval establishment studies were also inconclusive even though it was demonstrated that larval establishment was different among the cultivars used. The only definite evidence for poor establishment in some cultivars was biophysical.Different cultivars were significantly different in their susceptibility to leaf damage. The tendency to form deadhearts was also significantly different . But reasons for these differences were not apparent. Cultivars were not significantly different in their susceptibility to tunnelling even though they had different amounts of fibre, lignin and sucrose. The single most important factor for the different cultivar susceptibilities was in their different tolerances to C. partellus attack. Tillering, in particular, was demonstrated to play an important role in compensation for damage. The ability to flower and to produce seed inspite of having a high infestation were also very significant. Susceptible cultivars dried up before they had flowered. Others still, flowered but could not form seed. Using tolerance as a criterion for resistance showed IS 18520 to be the most resistant. Formation of multiple heads was also shown to be an important factor. Different cultivars had varying effects on the development of C. partellus (antibiosis). However , the antibiotic effect was either insignificant or only just significant statistically.

Knowledge attitudes and practices of registered nurses on scientific nursing research at the Kenyatta National Hospital

Author: Mukthar, Vincent Kiprono

Awarding University: University of Nairobi, Kenya

Level : MSc

Year: 0

Holding Libraries: University of Nairobi Medical Library ;

Subject Terms: Nurses ; Nursing ; Research ; Attitude surveys ;

Abstract:

Scientific Nursing Research is defined as the systematic process of investigating phenomena related to nursing with the aim of adding to the nursing body of knowledge, to improve practice and for better health care outcomes (Endrawes, 2000). This was a descriptive cross-sectional study aimed at assessing the knowledge, attitude and practice ofRNs on Scientific Nursing Research at the Kenyatta National Hospital. The study was undertaken-in 36 weeks, sample selection was by both stratified and convenient sampling. Data collection instrument was Structured Questionnaires. The findings were summarized, and presented in form of tables, graphs, and pie charts. Data analysis was done using Chi Square test of significance. The study findings indicate that whereby most of the RNs had been introduced to basic research concepts during training, only a minority (23%) had undertaken research, which corresponded with the percentage that undertaken update course. Over 50% of the respondent had positive attitudes and over 50% agreed that the factors hindering the access to research are lack of funds, lack of time and lack of supportive authorities. It was also established that only 30% had used research findings in their practice. In conclusion, most of the registered nurses are knowledgeable and have positive attitudes towards research. Though most of them exude confidence in performance of research, their practice is limited by factors of access to research e.g. funds, time and supportive authorities. The RNs use of research findings in their practice and attendance of update courses in research is wanting. The factors that significantly influenced the practice of research include ward placement, professional training background and attendance of update courses.

Comparison of simple interrupted Gambee and crushing techniques for intestinal anastomosis in cattle

Author: Mbiuki, Stanley Mbaka

Awarding University: University of Nairobi, Kenya

Level :

Year: 0

Holding Libraries: National Council for Science and Technology Library ; University of Nairobi Upper Kabete Library ;

Subject Terms: Comparative studies ; Intestinal anastomosis ; Animal care ; Cattle ;

Abstract:

End-on approximating techniques for intestinal anastomosis have been found to be more advantageous than everting and inverting techniques by different- investigators. The simple interrupted, gambeeand crushing anastomotic techriiques whEfn evaluated independently have usually been found to be superior to the techniques with which they were compared. Comparison of simple interrupted, gambee and crushing techniques together have not been previously reported. The purpose of -: this investigation .is to make a comparative study of the simple interrupted, gambee and crushing approximating techniques as used for intestinal anastomosis in cattle. Twenty four male cattle were used to perform anastomoses in the small intestine utilizing simple interrupted, gambee and crushing techniques for comparative studies. Six anastomoses were performed in each of 8 animals using any one of the techniques to make a total of 48 anastomoses per technique. Therefore one hundred fourty four anastomoses were performed using the three techniques. Evaluation'procedures were carried out at 4, 14, 28 and 56 days post-operatively to assess -c the efficacy of the respective techniques. Parameters investigated were: time per anastomosis and per stitch, adhesion formation,- stenosis (external and internal) and histopathologic changes. From the histologic sections, epitbelializati~n, inflammatory reaction, muscle layer approximation, cellular intensity and cell types were evaluated. I~crease in-thickness of anastomotic site relative to the adjacent and normal areas were also evaluated. Results of adhesion formation, external stenosis, epithelialization, inflammatory reaction, and muscle layer approximation were given numerical scores to make the comparison objective and easier to visualize. The results showed that time per suture was found to be a more reliable indicator of the time taken to perform an intestinal anastomosis. The simple interrupted technique took the least mean time per suture (36~6 sec.) followed by gambee technique (49.5 sec.) and crusbing technique was last with 57.4 seconds. There were no adhesions in 11% .of gambee' anastomoses, 58%.of crushing anastomoses and ? 21% of simple interrupted anastomoses. This clearly demonstrated gambee as the technique that induces least adhesions. Stenosis as seen externally was absent in 62% of gambee anastomoses, 531 of simple interrupted anastomoses and 40% o~ crushing anastomoses indicating that gamhee was a better technique in this regard. Luminal stenosis evaluated 1rom radio- graphs showed a mean narrowing o~ 30.6% in gambee anastomoses, 36% in simple interrupted anastomoses and 38.9% in crushi'I1? anastomoses, thus implying gambee was a superior technique. Epithelial healing was more or less complete at 4 days in simple in~errupted anastomoses followed by gambeeoastomoses with crushing anastomoses having poor epithe lia1 healing. However at 14 days. the healing in the crushing anastomoses overtook that in the other techniques. Simple interrupted anastomoses were inferior in the epithelial bealing to the anastomoses performed us i ng the other two techniques at 14 days. After 14 days all the anastomoses showed a similar degree of epithelial healing . Overall, gambee anastomoses had a slightly better epithelial he~ling than the other two techniques. Generally, inflammatory reaction decreased with time. There was a greater decrease in gambee anastomoses followed by crushing ana- stomoses and simple interrupted anastomoses? showed the greatest inflammatory reaction. Muscle layer approximation apparently did not change with time but remained as it was after anastomosis for all techniques. However, gambee anastomoses showed the best alignment followed by crushing anastomoses and simple interrupted anastomoses had least efficacy in alignment of the muscle layer. Cellular intensity was high in all the techniques at 4 days due to the increased number of cells in the early proliferative phase and late lag