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  A DELAYED TB-COVID-19 CO-INFECTION MODEL WITH OPTIMAL CONTROL ANALYSIS

  (UoEm, 2026-07-20)

  Edith Kathure Kiunye

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  Tuberculosis (TB) remains to be a threat affecting millions of people worldwide annually. This burden has been worsened by the emergence of COVID-19, and the coexistence of TB and COVID-19 has put more pressure on already strained health services. Although the public health efforts to manage the transmission of COVID-19 were essential, they resulted in socioeconomic effects, including decreased productivity, economic turmoil and unemployment. Epidemiologically, regions with high TB prevalence overlap creating conditions that increase the risk of co-infection and intensify public health vulnerability. For this reason, mathematical modeling of COVID-19 has shifted from merely creating epidemic curves only to examining more complex transmission dynamics and disease interaction. This work extends a deterministic TB–COVID-19 co-infection model into a delayed formulation by incorporating time lags related to both the diagnosis of active TB and the start of treatment. This approach captures a more realistic representation of healthcare system constraints and patient progression processes. This study seeks to identify cost-effective mitigation strategies for curbing the transmission of TB–COVID-19 co-infection through optimal intervention costs. Qualitative analysis is used to ascertain the model’s validity, including the positivity of solutions and the well-posedness of the model. The extended optimum control concern is formed and the analysis done using Pontryagin’s Maximum Principle, leading to the characterization of optimal intervention policies that minimize disease burden while reducing the implementation costs. Numerical simulations shows that combining the three measures i.e. vaccination, physical distancing and early treatment reduces the prevalence compared to using one method. The results also shows that time delays in TB diagnosis and treatment increases the disease transmissions.

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  A THESIS SUBMITTED IN PARTIAL FULFILMENT FOR THE AWARD OF THE DEGREE IN MASTER OF SCIENCE IN CHEMISTRY IN THE UNIVERSITY OF EMBU

  (UoEm, 2026-05-20)

  Ndung’u, John Kariuki

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  Substantial amounts of microplastics (MPs) enter sewer systems daily from domestic and industrial sewer effluents and therefore, making WWTP key sources of microplastics pollution in ecosystem. Nevertheless, research on their levels, occurrence, and removal efficiency in WWTPs remains limited, particularly across Sub-Saharan Africa. Thus the study aimed to investigate the occurrence of MPs from three Kenyan WWTPs (Dandora Estate Treatment Plant (D-WWTP), Thika Sewerage Treatment Works (T-WWTP), and Embu sewerage treatment plant (E-WWTP). Wastewater physicochemical parameters were measured in the site; wastewater was sampled using grab sampling, filtered through a stack of sieves, and treated with H 2 O 2 catalyzed with Fe 2+ to digest the organic matter. Microplastics (MPs) recovered were classified by both visual identification and ATR-FTIR spectroscopy. MPs were quantified in all treatment plants with abundances declining markedly: from 26.533±3.639 MPs/L in inlet to 0.0013±0.001 MPs/L in the outlet at D-WWTP, from 21.733±5.447 MPs/L to 0.034±0.014 MPs/L at T-WWTP and from 12.900 ± 1.296 MPs/L to 0.371 ± 0.04 MPs/L at E-WWTP. MP colors were mainly white or transparent, red, blue, green, black, yellow, and orange for the three treatment plants. On morphotypes, fibers were the most abundant shapes in E-WWTP, while in D-WWTP and T-WWTP, fragments were prevalent. Additionally, ATR-FTIR spectroscopy revealed 20 different polymers in D- WWTP with a blended polyethylene-polypropylene (PE-PP) (16.81%) been predominant polymer. While in T-WWTP, 27 different polymers were identified with polystyrene (21.47%) been the most common, and lastly 13 polymers in E-WWTP with polyacrylamide (PAM) (27.42%) been prevalent. Correlational analysis showed a weak positive relationship between MPs abundance and electro-conductivity and total phosphorus, salinity and total nitrogen. Since little knowledge is known about microplastics in Kenyan WWTPs, the present study lays a baseline data that can be utilized to inform policy on the usage of WWTPs effluents and also on management of plastic waste pollution.

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  ICT Adoption and Adoption Intensity among Tomato Farmers in Kenya

  (Society for Inovative Agriculture, 2026-10-07)

  Nyambura Nancy

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  Mogaka Hezron

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  Ndirangu Samuel N.

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  Gichimu Bernard M.

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  Access to timely, accurate, and relevant agricultural information is essential for improving productivity and decision-making among smallholder farmers. However, conventional extension systems in Kenya continue to face challenges related to limited coverage, inadequate staffing, and resource constraints. Information and Communication Technologies (ICTs), including mobile phones, internet-based platforms, social media applications, and SMS-based advisory services, offer alternative channels for delivering agricultural information and advisory services to farmers. Despite their potential, the adoption and effective utilization of ICT-based agricultural advisory services remain uneven among smallholder farmers. This study examined the socio-economic and institutional factors influencing both the adoption and adoption intensity of ICT-based agricultural advisory services among 384 smallholder tomato farmers in Kirinyaga County, Kenya. A cross-sectional survey design was employed, and respondents were selected through a multistage sampling procedure to ensure representative coverage of major tomato-producing wards in the county. A sequential modelling approach was adopted, using a Probit model to analyse the binary decision to adopt ICT-based advisory services and a Poisson regression model to examine adoption intensity, measured as the number of ICT-based agricultural advisory functions utilized by a farmer. The findings indicate that extension contact frequency and access to agricultural credit were positively associated with both ICT adoption and adoption intensity. Farmer group membership significantly increased the likelihood of ICT adoption, while household education positively influenced the intensity of ICT use. Conversely, larger tomato farm sizes were associated with lower adoption intensity. The results underscore the importance of human capital, institutional support, and financial inclusion in promoting meaningful engagement with digital agricultural advisory services. The study recommends strengthening farmer education and digital literacy initiatives, integrating ICTs into existing extension systems, improving access to agricultural credit, and promoting farmer group participation to enhance both the adoption and effective utilization of ICT-based agricultural advisory services. By jointly examining adoption and adoption intensity, the study contributes to the growing body of literature on digital agricultural extension and provides evidence to inform the design of inclusive and sustainable ICT-enabled advisory systems for smallholder horticultural farmers.

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  THE DISCURSIVE CONSTRUCTION OF THE 2024 GEN Z PROTESTS IN KENYAN NEWSPAPERS

  (UoEm, 2026-06-18)

  Joy, Karambu

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  This study explored the discursive construction of the 2024 Gen Z protests in Kenya’s newspapers. The study was guided by the following three objectives: To investigate the discursive construction of the Gen Z protesters in the Daily Nation and The Standard; To assess the discursive construction of the law enforcement officers during the Gen Z protests in the Daily Nation and The Standard; To examine how the Daily Nation and The Standard discursively constructed the strategies used by Gen Z during the 2024 protests. Data analysis was conducted using two complementary theoretical frameworks: Ruth Wodak's Discourse Historical Approach (DHA) and Chong and Druckman's (2007) Framing Theory. The DHA was adopted because it provides analytical discursive strategies which enabled systematic analysis of how language constructed the social actors and the protest events. Framing Theory was employed because it explains how media texts select and emphasise certain aspects of reality to promote particular interpretations of events. A total of 62 texts were sampled from the Daily Nation and The Standard: 21 front-page news headlines, 13 editorials, and 28 news articles published in June 2024. This period was selected because it represents the peak of the protest activity. Both newspapers were selected because they command the widest readership in Kenya, with the Daily Nation at 35% and The Standard at 21% of the national readership, according to the State of Media Report 2023/2024 by the Media Council of Kenya. The findings revealed three systematic patterns. First, both newspapers overwhelmingly constructed the Gen Z protesters positively as revolutionaries, patriots, and representatives of the entire Kenyan nation. They were attributed qualities of peacefulness, civility, and bravery, and their actions were constitutionally mandated. This positive construction was reinforced through intertextual references to various global movements and laws positioning protesters as legitimate defenders of democratic order. Second, both newspapers consistently constructed law enforcement officers in a negative manner. Nominations escalated from neutral labels such as "police officers" to condemnatory terms such as "killer plainclothes police." They were constructed largely as brutal, and as violators of the constitution. Third, Gen Z's protest strategies were constructed as innovative, technologically sophisticated, and unprecedented. Digital platforms, the leaderless structure, and accountability tools such as the "Wall of Shame" website were framed as legitimate instruments of democratic participation superior to formal state accountability mechanisms. This study contributes to the disciplines of discourse studies, media studies, and political communication. The newspapers constructed the technological strategies as powerful tools that the youths can use to oversight the government, a role that is traditionally performed by Parliament. The framing of the protest as an in-group versus an out-group situation, has important implications in media studies in that grassroots groups as opposed to the elite, can attain newsworthiness. It was established that reference to the past global protests gave legitimacy to the 2024 protests. This implies that global occurrences have an influence on subsequent political actions.

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  A CRITICAL DISCOURSE ANALYSIS OF KENYAN DAILY NEWSPAPERS’ REPRESENTATION OF NATIONAL EXAMINATIONS CHEATING

  (UoEm, 2026-05-20)

  Othuon, Judith Akoth

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  Although there are considerable studies on examination cheating globally and in Kenya, there is limited focus on how the media discursively construct the phenomenon. The study explored Kenyan daily newspapers’ representation of national examinations cheating guided by the following objectives: to examine how the act of examination cheating is discursively constructed in Kenyan daily newspapers; to investigate how social actors in national examination cheating are discursively constructed in Kenyan daily newspaper; to evaluate how the measures against examination cheating are discursively constructed in Kenyan daily newspapers. Data was drawn from the Daily Nation and The Standard, Kenyan newspapers with the widest readership. Focus was given to the news and opinion articles, and their headlines. The study focused on the period between 2022 and 2024, a period that was characterized by the massive development in the use of Artificial Intelligence (AI), which contributed to ease of cheating. It further concentrated on the months of November and December and a month post- result release, a period when there is usually wide coverage of examination issues. Sampling followed a cyclic and iterative procedure until discursive saturation was reached. The study was guided by Fairclough’s Critical Discourse Analysis (CDA) which is both a theory and a method. It further adopted Michel Foucault’s theory of disciplinary power. CDA was employed to make transparent linguistic and discursive strategies through which examination cheating and its aspects are constructed in newspapers’ discourse. Foucault’s theory of disciplinary power provided a broader sociological lens to explain how the discursive constructions relate to mechanisms of surveillance, normalization and punishment. This integration enhanced triangulation, making it possible to connect micro-level textual choices to macro-level structures of power. The analysis was further complemented by corpus tools; AntConc (Version 4.3.1) to aid in finding frequencies, salient lexical and grammatical patterns and SKELL Engine to further support the analysis of collocations. The findings reveal that the act of examination cheating is dominantly constructed as a crime rather than as a structural problem embedded within the education system. Through naming and reference, collocations, over wording, and metaphors, cheating is framed as a threat that must be battled, contained, and eradicated. Grammatical patterns such as modality, nominalization and grammatical processes foreground cheating act as deviance while backgrounding structural pressures such as high-stakes testing and inequality. Institutional actors are positioned as competent and morally committed guardians of national integrity. Non- institutional actors like students are labelled as cheats; teachers are represented as professional traitors; parents appear as facilitators; and barely named criminalized groups are constructed as cartels and syndicates. Institutional and elite voices dominate the discourse, while the perspectives of students, parents, and other non-elite actors are marginalized or silenced. Measures against national examination cheating are naturalized as inevitable, necessary and sufficient by constructing them as punitive and deterrent, security and surveillance operation, legally mandated, technological and reform-oriented. Examinations emerge as tools that render individuals visible, measurable, and correctable, while legitimizing expanded surveillance and punitive control. The study concludes that Kenyan newspapers do not merely report on cheating; they normalize institutional authority, reproduce their discourses and sustain them. This study offers insights into linguistic and discursive strategies used in examination cheating discourse, important to linguists. It also informs journalistic practices in reporting about examination cheating. It is hoped that it will contribute to education reforms, specifically on matters of assessment and evaluation.

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