School of Pure and Applied Sciences
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Item Students Selection for University Course Admission at the Joint Admissions Board (Kenya) Using Trained Neural Networks(2011) Wabwoba, Franklin; Mwakondo, Fullgence M.Every year, the Joint Admission Board (JAB) is tasked to determine those students who are expected to join various Kenyan public universities under the government sponsorship scheme. This exercise is usually extensive because of the large number of qualified students compared to the very limited number of slots at various institutions and the shortage of funding from the government. Further, this is made complex by the fact that the selections are done against a predefined cluster subjects vis a vis the student’s preferred and applied for academic courses. Minimum requirements exist for each course and only students having the prescribed grades in specific subjects are eligible to join that course. Due to this, students are often admitted to courses they consider irrelevant to their career prospects and not their preferred choices. This process is tiresome, costly, and prone to bias, errors, or favour, leading to disadvantaging innocent students. This paper examines the potential use of artificial neural networks at the JAB for the process of selecting students for university courses. Based on the fact that Artificial Neural Networks (ANNs) have been tested and used in classification, the paper explains how a trained neural network can be used to perform the students’ placement effectively and efficiently. JAB will be able, therefore, to undertake the students’ placement thoroughly and be able to accomplish it with minimal wastage of time and resources respectively without having to utilise unnecessary effort. The paper outlines how the various metrics can be coded and used as input to the ANNs. Ultimately, the paper underscores the various merits that would accompany the adoption of this technique. By making use of neural networks in the university career choices, student placement at JAB will enhance the chances of students being placed into courses they prefer as part of their career choice. This is likely to motivate the students, making them work harder and leading to improved performance and improved completion rate. The ANN application may also reduce the cost spend on the application processing and the time the applicants have to wait for the outcome. The ANN application could further increase the chances of high quality applicants getting admission to career courses for which they qualify.Item Classifying Program Visualization Tools to Facilitate Informed Choices: Teaching and Learning Computer Programming(2012) Mutua, Stephen; Wabwoba, Franklin; Ogao, Patrick; Anselmo, Peter; Abenga, Elizabeth1Program Visualization (PV) is a technique that has been found useful in teaching computing programming. This has seen proliferation in development of PV tools with an aim of enhancing teaching/learning programming over the last two decades. However, the tools usage has remained minimal. Perhaps because it becomes challenging to ascertain the appropriate tool for the right task. This paper presents a classification of program visualization tools with the focus of aiding teachers and students in choosing the most appropriate tool for an interesting experience in the classroom. The paper is based on six various PV tools evaluated over a period of two consecutive academic years in a Kenyan public University. The classification augments the Price’s taxonomy of software visualization arm of PV by presenting four basic levels which are further subdivided into lower levels. Index Terms– Classification, Pedagogy, Program Visualization and TaxonomyItem Virtual reality in education trends and issues(2013-01-01) Omieno, Kelvin K.; Wabwoba, Franklin; Matoke, Nahasoncommon form of education in institutions of higher learning (IHL). Many IHL in developing nations, such as Kenya, have greatly experienced an increase in demand for higher education. On the other hand, the ability to connect people with required sets of skills, regardless of their location in the world has been enabled by advances in information technology over the past 20 years. Use of virtual learning systems (VLS) has rapidly emerged as a very promising technology that will probably match the innovation of technologies such as multimedia/hypermedia. These VLS have the potential to provide opportunities for active, flexible, and increasingly individualized learning experiences. It also explains virtual reality principle, describes the interactive educational environment, highlights the challenges higher education face in the traditional mode of delivery and discusses educational benefits of implementing virtual learning environments in IHL. The paper makes a number of recommendations for successful adoption of VLS in higher educationItem Barriers to Implementation of Green ICT in Kenya(2012) Wabwoba, F.; Wanyembi, Gregory W.; Omuterema, StanleyABSTRACT Information and Communication Technology (ICT) is playing an increasingly important role in both business and private undertakings. Its use in several areas in the world economy has brought about increased demand for electronic equipment. The rapid pace of technology advancement and the drop in hardware prices has led to increased demand and acquisition resulting in increased production and use of hardware. However, the increased ICT uptake has increased costs and demand for energy where electricity is the main power source. Electricity notably is a major contributor to climatic change because the coal or oil that helps generate it does releases carbon dioxide, pollutants, and sulphur into the atmosphere. With environmental degradation, rising costs of doing business and power demand and demand for social responsibility, going green is no longer an option. There are green ICT technologies in the market to mitigate the concerns but unfortunately they are not bearing fruit that calls for an understanding of barriers to implementation of the same in developing nations like Kenya. The study used multiple case study approach. The study population included ICT managerial, technical and end user human resource and public university ICT graduate students. The multiple study was conducted in one leading sugar manufacturing industry, a communication commission regulatory body and one public university offering ICT from certificate to PhD level. Respondents were either interviewed or responded to a questionnaire. The study established that green ICT technologies are available in Kenya and are not barriers to its implementation. The paper highlights the barriers to implementing green ICT in Kenya. The paper recommends alignment of ICTItem The Impact Of Policy Changes In The Education Sector On The Development Of The Book Publishing Industry In Kenya(Unisa Press, 2009) Mbengei, Bernard; Francis, GallowayThis article explores the impact of policy changes in the education sector on the de-velopment of the book publishing sector in Kenya. The article begins by detailing the current status of the book publishing sector in Kenya. Then the interdependence between the education and book publishing sectors is highlighted. The government policies that have shaped the education system in Kenya are analysed with a view to establishing how they have affected the book publishing sector. An overview of the new school textbook policy that was introduced in 1998 is presented in order to show how it has influenced the textbook production and procurement. Then the introduction of the Free-Primary Education (FPE) is discussed because it is the most recent development in the education sector that has provided tremendous impetus to the development of the book publishing industry in the country. The challenges encountered by the Government of Kenya in implementing the FPE and those faced by the book publishers in producing books for the school market are analysed. Finally, a way forward is proposed in the form of recommendations that can contribute to positive growth and mainstreaming of the school textbook publishing sub-sector in Kenya. A literature review approach isused in which sources that include newspapers, government and institutional websites, journals, books and dissertations have been consulted.Item Functional response of Orius albidipennis (Hemiptera: Anthocoridae) to Megalurothrips sjostedti (Thysanoptera: Thripidae)(Karatina University, 2002-05-02) Gitonga (a), Linus M.; Löhrb (b), B.; Magambo (a), J. K.; Mueke (c), J. M.A locally available anthocorid predator, Orius albidipennis Reuter, was evaluated as a candidate biocontrol agent for Megalurothrips sjostedti Trybom, a major pest of French beans, Phaseolus vulgaris (L), in Kenya. The functional response of adult O. albidipennis to larval and adult M. sjostedti was studied at 15, 25, and 28 °C and densities of 5, 10, 20, and 30 larval and adult M. sjostedti per cage, over 24 h. More larvae and adult M. sjostedti were killed at the higher densities and with an increase in temperature. The data provided good fit to both type I and II functional response models. Attack rates increased with temperature for both the second instar larva and adult M. sjostedti. Handling times for the larvae decreased with an increase in temperature while those for the adults increased with increase in temperature. The implications of these results are discussed.Item Bioecology of thrips in French bean growing ecosystem in Kenya(2012-10-31) Gitonga, Linus MuthuriStudies on the bioecology ofthrips on French beans were carried out at Machakos, Kaguru and JKUAT. The general objectives of this study were twofold, namely to study the biology and population dynamics of thrips on French beans and to identify and evaluate indigenous natural enemies of the thrips. Two thrips species, M sjostedti and F occidentalis were found throughout the year on French bean crops in all localities of the study. Their population peaks occurred at different times in the course of the year. Populations of M sjostedti peaked after the rains while those of F occidentalis occurred during the hot and dry months of the year at all the localities. Studies on the movements of thrips, into and out of the French bean crops showed that colonization by both species begins soon after germination and that both species preferred the flowers to other plant parts. F occidentalis was found to thrive equally well on the leaves, unlike M sjostedti which only inhabited flower buds and flowers. During the pre-flowering phase ofthe crop, M sjostedti were found on the terminal buds from where they moved to the flowers immediately after the onset of flowering. Most first instar larvae emerged from the pods and flowers. Petioles, leaves, flower buds, flowers and pods were used as oviposition substrates by the thrips.to varying extents. Analysis of the spatial distribution showed both species to be significantly aggregated in the respective plant parts. Laboratory studies indicated that developmental period decreased with an increase in temperature for all the stages of M sjostedti and F. occidentalis. Developmental threshold temperatures were calculated as 9.6 and 9.0 for M sjostedti and F. occidentalis respectively. Development from egg to adult required 212.0 and 256.8 Degree Days for M sjostedti and F. occidentalis respectively. However, at 15?C and 300C, mortality rates for all the developmental stages were higher for M sjostedti than F. occidentalis. The highest mortalities were recorded for the first instar larvae for both species, ranging from 15% to 42% and 11 % to 30% for M sjostedti and F. occidentalis respectively. Pre-pupae and pupae had the lowest mortality rates. An indigenous anthocorid bug, Orius albidipennis was found throughout the year in all the three field sites. Studies on the functional responses of 0. albidipennis to M sjostedti showed that more second instar larvae than adult M sjostedti were killed at all the temperature profiles and densities. With increase in temperature, more second instar larvae and adult M sjostedti were killed. High f2 values shows that both Types I and IT functional responses provided good fit for the data at 15?C, 25?C and 28?C. Attack rates also increased with an increase in temperature. Mortality rates of the 0. albidipennis nymphal instars decreased from the first to the 5th instar at all the temperatures. The mortality rates at 25?C were lower than at 20?C and 30?C for all the nymphal instars except the first instar. Temperatures had a significant effect on the pre-oviposition period, which decreased with an increase in temperature. The eggs took long to hatch at 20?C. Developmental periods of each of the nymphal instars decreased with an increase in temperature. An indigenous larval endoparasitoid of thrips, Ceranisus menes, was found throughout the year in the three localities and its population peaks occurred in the late and early months of the year, from October to April. A closer correlation was found between C. menes and F. occidentalis than with M sjostedti. At JKUAT, percentage parasitism, over the entire crop cycle, ranged from 3.5% to 19.5% and peaked in the months of Marchi April. The lowest percentage parasitism coincided with the period of the highest M sjostedti infestation on French beans. Linear regression analysis showed a density dependence relationship between parasitism and larval density. Laboratory experiments showed that C. menes successfully parasitized and completed development in both M sjostedti and F. occidentalis. Developmental times of C. menes in M sjostedti and F. occidentalis were not significantly different.Item Temperature-dependent development of Megalurothripssjostedti and Frankliniellaoccidentalis (Thysanoptera: Thripidae)(2002-09) Gitonga, Linus; Lohr, B.; Overholt, Bill; Magambo, J. K.Megalurothrips sjostedti (Trybom) and Frankliniella occidentalis (Pergande) (Thysanciptera: Thripidae) are among the most serious pests of French beans, Phaseolus vulgaris var. Monel in Kenya and occur in all major growing areas. The former seems to be prevalent during cold and rainy periods while the latter is mainly a problem during hot and dry conditions. The development of the two species was studied at temperatures ranging from 15 degreesC to 30 degreesC. The average developmental times of each stage are given. For both species, the developmental times decreased with an increase in temperature. The degree-days required to complete development from egg to adult were 212 and 256 above the estimated threshold temperatures of 9.6 degreesC and 9.0 degreesC for M. sjostedti and F.occidoitalis, respectively. Between 19 and 23 generations of M. sjostedti and between 17 and 20 generations of F. occidentalis; could possibly develop under Kenyan field conditions in one year. Overall mortality was lowest at 25 degreesC. Mortality rates for both species decreased from larval instars to adult and were higher for M. sjostedti than for F. occidentalis. Since the developmental times were not different, the differential pest status of M. sjostedti and F. occidentalis must be a result of other factors.Item Antimicrobial acitivity of extracts from Tephrosiavogelii Hook F.(Jomo Kenyatta University of Agriculture & Technology (JKUAT), Kenya, 2006) Wanga, B. N.; Akenga, T.; Imbuga, M.; Gitonga, L.; Olubayo, F.; Namungu, P.The dichloromethane extracts of the root and leaf of Tephrosia vogelii Hook F. (Family: Papilionaceae) grown in Kenya, were subjected to antimicrobial assays against Staphylococcus aureus, Escherichia coli and Fusarium phoseolida. The minimum inhibition concentrations (MIC) ranged between 0.25 to 6.4 μg/ml for all the microorganisms tested. The crude root and leaf extracts were also toxic to the brine shrimps, organisms used as indicators of toxicity (LC50: 0.960; 0.958μg/ml,respectively). Chromatographic separation led to the identification of (6aß, 12aß, 5'ß)-6a, 12a, 4',5'-tetra hydro-2,3-dimethoxy 5'-ß- isopropenyl–furano (3',2': 8,9)-6H-rotoxen-12-one, (rotenone) in 9.75% yield, (roots), and 11.75% (leaves). Characterisation was achieved by use of spectroscopic techniques and comparison with rotenone standard and literature data. Novel HPLC conditions for purification of rotenoids were established. The MIC of rotenone against the tested microbes was found to be 5.2 and 1.0 μg/ml for Staphylococcus aureus and Escherichia coli respectively, while the LC50 against the brine shrimps was found to be 3.20 μg/ml. The findings indicate that the extracts of T. vogelii contain metabolites that have antimicrobial activity comparable to other medicinal plants.Item Interaction between Phaedrotomascabriventris Nixon and Opiusdissitus Muesebeck (Hymenoptera: Braconidae) : endoparasitoids of Liriomyza leafminer(Sabinet African Journals, 2015-03-01) Foba, C.N.; Akutse, K.S.; Fiaboe, K.K.M.; Lagat, Z.O.; Gitonga, L.M.The exotic parasitoid, Phaedrotoma scabriventris Nixon, was imported from Peru for the biological control of invasive Liriomyza species in vegetable and ornamental crops in Kenya where Opius dissitus Muesebeck is the most abundant indigenous Liriomyza parasitoid. Both species are solitary larva-pupal endoparasioids attacking the same larval stage. In order to assess whether these two species compete or co-exist, an interaction study involving sole, sequential and simultaneous releases of the two species on polyphagous Liriomyza huidobrensis (Blanchard) was conducted in the laboratory at the International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya. Simultaneous releases of 50 individuals each of the two parasitoids resulted in significantly higher total parasitism rate (61.96 ± 4.60) than in the single release of P. scabriventris (34.94 ± 8.50). Simultaneous release of 25 individuals of each species resulted in a parasitism rate (44.52 ± 2.75) similar to that obtained for single releases of 50 individuals of O. dissitus (42.57 ± 3.35) and P. scabriventris (34.94 ± 8.50). No significant effect was observed in total parasitism between sequential and single releases of 50 individuals of each species. The specific parasitism rate of each parasitoid species in the simultaneous release of 50 individuals of each species was not significantly different from when each species was released alone. The first introduced parasitoid in sequential releases achieved the same parasitism rate as when released alone. However, the second released species gave a significantly lower parasitism rate than when released alone and compared to the first released species. The F1 progeny sex ratio was balanced for P. scabriventris but male-biased in O. dissitus. The sex ratios of both parasitoid species were not significantly affected, neither in simultaneous nor sequential releases, except in one of the sequential release where P. scabriventris was released second, with its sex ratio significantly female-biased. Non-reproductive host mortality was not important for both parasitoids when used alone and in combined releases compared to the natural mortality observed in the control. These findings suggest that P. scabriventris has no detrimental effect on O. dissitus and its release into Kenya's agricultural ecosystems will enhance the management of Liriomyza leafminer.