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"Ochieng"
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Managing climate risk through crop diversification in rural Kenya
Climatic variability and change continue to militate against efforts to increase agricultural productivity and food and nutrition security in many developing countries. Several studies propose crop diversification as a climate risk management strategy to increase production and food security. Most of the empirical studies are based on cross-sectional data that do not account for unobserved factors that may affect crop diversification. A disaggregated analysis of the influence of climatic variability and change on crop diversification by agroecological profiles is less explored. Panel studies also do not combine more than one climatic variability and change indicator as we do. We employ panel data models on farm household and 31-year rainfall and temperature data to analyze the effects of climatic variability and change on crop diversification among small-scale farmers disaggregated by agroecological zones in Kenya. We find widespread crop diversification among small farms in warmer regions as a risk management strategy. Results further show that smaller farm size, limited use of inorganic fertilizer, low household incomes, and limited access to off-farm livelihood options influence the decision to diversify crop production. However, crop diversification is not a one-size-fits-all strategy and should be adopted in situations where it gives maximum benefits, consistent with existing land use policies and known benefits of a specified crop portfolio. Crop diversification should not crowd-out specialization, particularly among resource-endowed farmers.
Journal Article
Legislative development in Africa : politics and postcolonial legacies
\"What explains contemporary variations in African legislative institutions -- including their strengths and weaknesses? Compared with more power executive branches, legislatures throughout the continent have historically been classified as weak and almost inconsequential to policy-making processes. But as Ken Ochieng' Opalo suggests here, African legislatures actually serve important roles, and under certain conditions, powerful and independent democratic legislatures emerge from their autocratic foundations. In this book, Opalo examines the colonial origins of African legislatures, as well as how post-colonial intra-elite politics sought to adapt inherited colonial legislatures to their respective local political contexts. By focusing on the case studies of Kenya and Zambia, Opalo offers a comparative longitudinal study of legislative strength and institutionalization as well as a regional survey of legislative development under colonial rule, post-colonial autocratic single party rule, and multiparty politics throughout Africa\"--Provided by publisher.
Book
Africa triples health workforce in 10 years, but unemployment is a problem
African countries increased their health workforce from 1.6 million in 2013 to 5.1 million in 2022, alongside improvements in training and data use, a review by the World Health Organization Africa region office has found.1 The decade also saw a 44% increase in the number of countries with national health workforce strategies, from 27 in 2018 to 39 in 2022. Since 2018 at least 14 countries have had at least four health worker strikes a year because of dissatisfaction with conditions, another problem affecting the continent’s health sector, according to Asamani. A decade review of the health workforce in the WHO African Region, 2013-2022: implications for aligning investments to accelerate progress towards universal health coverage.
Journal Article
Deep neural network techniques for monaural speech enhancement and separation: state of the art analysis
Deep neural networks (DNN) techniques have become pervasive in domains such as natural language processing and computer vision. They have achieved great success in tasks such as machine translation and image generation. Due to their success, these data driven techniques have been applied in audio domain. More specifically, DNN models have been applied in speech enhancement and separation to perform speech denoising, dereverberation, speaker extraction and speaker separation. In this paper, we review the current DNN techniques being employed to achieve speech enhancement and separation. The review looks at the whole pipeline of speech enhancement and separation techniques from feature extraction, how DNN-based tools models both global and local features of speech, model training (supervised and unsupervised) to how they address label ambiguity problem. The review also covers the use of domain adaptation techniques and pre-trained models to boost speech enhancement process. By this, we hope to provide an all inclusive reference of all the state of art DNN based techniques being applied in the domain of speech separation and enhancement. We further discuss future research directions. This survey can be used by both academic researchers and industry practitioners working in speech separation and enhancement domain.
Journal Article
Technical Note: Large overestimation of pCO2 calculated from pH and alkalinity in acidic, organic-rich freshwaters
Inland waters have been recognized as a significant source of carbon dioxide (CO2) to the atmosphere at the global scale. Fluxes of CO2 between aquatic systems and the atmosphere are calculated from the gas transfer velocity and the water-air gradient of the partial pressure of CO2 (pCO2). Currently, direct measurements of water pCO2 remain scarce in freshwaters, and most published pCO2 data are calculated from temperature, pH and total alkalinity (TA). Here, we compare calculated (pH and TA) and measured (equilibrator and headspace) water pCO2 in a large array of temperate and tropical freshwaters. The 761 data points cover a wide range of values for TA (0 to 14 200 μmol L-1), pH (3.94 to 9.17), measured pCO2 (36 to 23 000 ppmv), and dissolved organic carbon (DOC) (29 to 3970 μmol L-1). Calculated pCO2 were >10% higher than measured pCO2 in 60% of the samples (with a median overestimation of calculated pCO2 compared to measured pCO2 of 2560 ppmv) and were >100% higher in the 25% most organic-rich and acidic samples (with a median overestimation of 9080 ppmv). We suggest these large overestimations of calculated pCO2 with respect to measured pCO2 are due to the combination of two cumulative effects: (1) a more significant contribution of organic acids anions to TA in waters with low carbonate alkalinity and high DOC concentrations; (2) a lower buffering capacity of the carbonate system at low pH, which increases the sensitivity of calculated pCO2 to TA in acidic and organic-rich waters. No empirical relationship could be derived from our data set in order to correct calculated pCO2 for this bias. Owing to the widespread distribution of acidic, organic-rich freshwaters, we conclude that regional and global estimates of CO2 outgassing from freshwaters based on pH and TA data only are most likely overestimated, although the magnitude of the overestimation needs further quantitative analysis. Direct measurements of pCO2 are recommended in inland waters in general, and in particular in acidic, poorly buffered freshwaters.
Journal Article
Dozens of telehealth companies are innovating in Africa
Telehealth is poised to grow into big business in Africa, with home-grown and imported start-ups offering child and maternal health education, remote diagnosis, prescription services and more.
Journal Article
SEIRS model for TB transmission dynamics incorporating the environment and optimal control
Tuberculosis (TB) remains a significant global health challenge, claiming more than 2 million lives annually, predominantly among adults. Existing studies often neglect the environment, reinfection, relapse/reactivation, and model calibration, thus limiting their applicability. This study presents a novel data-driven model that incorporates these factors to analyze the dynamics of TB transmission. Using the next-generation matrix approach, a basic reproduction number (
R
0
) of 1.737266 was calculated, indicating that active TB disease will persist in the human population without robust public health interventions. The model equations were numerically solved using fourth- and fifth-order Runge-Kutta methods. The model was calibrated to the historical TB incidence data for Kenya, spanning 2000 to 2022, using least squares curve fitting. The fitting algorithm yielded a mean absolute error (MAE) of 0.01% when comparing the actual data points with the results of the simulated model. This finding indicates that the proposed mathematical model closely aligns with the recorded TB incidence data. The optimal values of the model parameters were estimated from the fitting algorithm, and future TB transmission dynamics was projected for the next two decades. Key findings indicate that a 10% decrease in transmission rate, while maintaining other parameters constant, would result in a 10% reduction in TB transmission in Kenya. In addition, the incidence of tuberculosis in Kenya is expected to decrease to an estimated 35 cases per 100,000 people by 2045 with sustained efforts in Bacillus Calmette-Guérin (BCG) vaccination programs and public awareness campaigns. BCG vaccination emerges as the most cost-effective strategy to combat TB transmission in Kenya. Policymakers should prioritize investing in BCG vaccination programs to achieve optimal public health outcomes and economic benefits, aligning with Kenya’s Vision 2030.
Journal Article
High seroprevalence of Immunoglobulin G (IgG) and IgM antibodies to SARS-CoV-2 in asymptomatic and symptomatic individuals amidst vaccination roll-out in western Kenya
The population’s antibody response is a key factor in comprehending SARS-CoV-2 epidemiology. This is especially important in African settings where COVID-19 impact, and vaccination rates are relatively low. This study aimed at characterizing the Immunoglobulin G (IgG) and Immunoglobulin M (IgM) in both SARS-CoV-2 asymptomatic and symptomatic individuals in Kisumu and Siaya counties in western Kenya using enzyme linked immunosorbent assays. The IgG and IgM overall seroprevalence in 98 symptomatic and asymptomatic individuals in western Kenya between December 2021-March 2022 was 76.5% (95% CI = 66.9–84.5) and 29.6% (95% CI = 20.8–39.7) respectively. In terms of gender, males had slightly higher IgG positivity 87.5% (35/40) than females 68.9% (40/58). Amidst the ongoing vaccination roll-out during the study period, over half of the study participants (55.1%, 95% CI = 44.7–65.2) had not received any vaccine. About one third, (31.6%, 95% CI = 22.6–41.8) of the study participants had been fully vaccinated, with close to a quarter (13.3% 95% CI = 7.26–21.6) partially vaccinated. When considering the vaccination status and seroprevalence, out of the 31 fully vaccinated individuals, IgG seropositivity was 81.1% (95% CI = 70.2–96.3) and IgM seropositivity was 35.5% (95% CI = 19.22–54.6). Out of the participants that had not been vaccinated at all, IgG seroprevalence was 70.4% (95% CI 56.4–82.0) with 20.4% (95% CI 10.6–33.5) seropositivity for IgM antibodies. On PCR testing, 33.7% were positive, with 66.3% negative. The 32 positive individuals included 12(37.5%) fully vaccinated, 8(25%) partially vaccinated and 12(37.5%) unvaccinated. SARs-CoV-2 PCR positivity did not significantly predict IgG (p = 0.469 [95% CI 0.514–4.230]) and IgM (p = 0.964 [95% CI 0.380–2.516]) positivity. These data indicate a high seroprevalence of antibodies to SARS-CoV-2 in western Kenya. This suggests that a larger fraction of the population was infected with SARS-CoV-2 within the defined period than what PCR testing could cover.
Journal Article