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Pollen Amount and Viability in Mchare and Selected Wild (AA) Banana (Musa acuminata) Genotypes: Prospects for Breeding
Get PDFThis research article was published by HortScience, 2024East African diploid cooking bananas, commonly called Mchare, are a staple crop for millions of subsistence farmers in Tanzania, particularly in the Pangani region in northern Tanzania. Several pathogens constrain Mchare production significantly and threaten food security. Sources of resistance to these pathogens have been identified; however, partial male and female sterility impedes successful resistance introgression, complicating the breeding process. Mchare cultivars are also the only known surviving representatives of a diploid banana subgroup that contributed unreduced gametes to many of the most widely grown and successful triploid dessert bananas (‘Cavendish’, ‘Gros-Michel’, ‘Silk’, and ‘Prata’). As such, they represent an essential intermediate step in the conventional improvement of bananas worldwide. We assess the amount and viability of pollen among Mchare and wild genotypes to identify the most fertile Mchare cultivars that can be used in conventional banana improvement. Pollen was collected from 14 banana genotypes for quantification and viability testing over 7 months, and the optimal time for pollen collection was determined to be 0800 HR. Significant variation among banana genotypes in terms of both overall pollen production and percentage of pollen viability was observed. The wild-type bananas ‘Calcutta 4’ [International Musa Germplasm Transit Center (ITC) 0249] and ‘Borneo’ (ITC0253) had the greatest overall pollen production (> 31,000 pollen grains/anther) and viability (∼74%), whereas ‘Ijihu Inkundu’ (ITC1460; Mchare genotype) was the least productive (almost completely sterile), with an average pollen production of a few hundred grains per anther and a viability of 7%. There were significant differences among months in terms of pollen viability, with the greatest average viability observed in May, April, and February (> 51%), and the lowest average pollen viability in July (41%). Significant differences were observed among the Mchare genotypes, with ‘Huti-White’, ‘Huti green bell’ (ITC1559), and ‘Mchare Laini’ consistently producing more substantial amounts of total pollen and an overall more significant proportion of viable pollen. This information is vital to improve Mchare bananas and the global breeding of dessert bananas. The choice of Mchare banana used in improvement programs could affect fertility and the likelihood of breeding success
The role of asymptomatic carriers on the dynamics of a lymphatic filariasis model incorporating control strategies
Get PDFThis Research Article was published by the Results in Control and Optimization
Volume 15, 2024This study presents a mathematical model to investigate the patterns of transmission in lymphatic filariasis. The model considers chronic, acute, and asymptomatic individuals and integrates key control strategies. Random synthetic data is generated robustly through numerical solutions to closely replicate real-world scenarios and encompass uncertainties. The synthetic data adheres to a Gaussian distribution to ensure validity and reliability. Following the derivation of the basic and effective reproduction number using the next generation matrix approach, Latin Hypercube Sampling (LHS) and the Partial Rank Correlation Coefficient (PRCC) algorithm is utilized to assess the parameters that significantly influence the model outputs. The study examine the trajectories of different population compartments through numerical simulations over time, with particular emphasis on the role played by asymptomatic individuals in the transmission of the disease. To assess the potential for disease elimination, the study introduces a range of strategies involving protective measures, treatment interventions, and mosquito control. These strategies are determined through sensitivity analysis. The findings demonstrate that the simultaneous implementation of all control measures has a noteworthy effect in managing lymphatic filariasis. In conclusion, the proposed model enhances understanding of lymphatic filariasis dynamics and informs effective control strategies
Mathematical modeling of vehicle carbon dioxide emissions
Get PDFThis research article was published in the Heliyon, 2024The demand for transportation, driven by an increasing global population, is continuously rising.
This has led to a higher number of vehicles on the road and an increased reliance on fossil
fuels. Consequently, the rise in atmospheric carbon dioxide (2) levels has contributed to
global warming. Therefore, it is important to consider sustainable transportation practices to
meet climate change mitigation targets. In this research paper, a non-linear mathematical model
is developed to study the dynamics of atmospheric 2 concentration in relation to human
population, economic activities, forest biomass, and vehicle population. The developed model
is analyzed qualitatively to understand the long-term behavior of the system’s dynamics. Model
parameters are fitted to actual data of world population, human economic activities, atmospheric
2, forest biomass, and vehicle population. It is shown that increased vehicular 2 emissions
have a potential contribution to the increase in atmospheric 2 and the decline of human
population. Numerical simulations are carried out to verify the analytical findings and we
performed global sensitivity analysis to explore the impacts of different sensitive parameters on
the 2 dynamics
Molecular assessment of genetic diversity of Tanzanian and aflatoxin-resistant maize (Zea mays. L) accessions
Get PDFThis research article was published by Springer International Publishing,2024Genetic distance information for various maize accessions is important for germplasm improvement and breeding program. However, this information is limited in most of the developing countries such as Tanzania. The present study was conducted to analyze the genetic diversity between Tanzanian maize accessions and the International Maize and Wheat Improvement Center (CIMMYT) lines as a strategy to create heterotic groups for maize breeding. Thirty Tanzanian maize accessions (14 inbred lines, 8 open-pollinated varieties, and 8 landraces) and 10 tester lines from CIMMYT were studied to estimate the molecular genetic variability using Euclidean distance determined by simple sequence repeat (SSR) markers. Fifteen SSR markers, resulting in general maize alleles, were used to determine genetic diversity, where 13 markers were amplified with an average PIC of 0.73. Where a moderate genetic distance between Tanzanian maize accessions and resistant lines, ranging from 0.13 to 0.57, was determined. The 40 maize genotypes (testers and accessions) were studied by using SSR markers classified into three major groups and further divided into 5 subgroups, which were later used to create the heterotic groups. The heterotic groups drawn and determined in phylogenetic tree showed distinct variations among studied genotypes. The study concludes that there is significant (P < 0.001) genetic diversity among the maize genotypes, which are essential breeding materials for producing superior maize hybrids with high combining ability and high heritability of traits of interest, such as high yielding and resistance to aflatoxin contamination. Thus, Tanzanian maize breeders can utilize the available maize genotypes to develop hybrids with high yield and resistance to aflatoxin contamination
Frequentist and Bayesian Approaches in Modeling and Prediction of Extreme Rainfall Series: A Case Study from Southern Highlands Region of Tanzania
Get PDFThis Research article was Published in the Advances in Meteorology, 2024This study focuses on modeling and predicting extreme rainfall based on data from the Southern Highlands region, the critical for
rain-fed agriculture in Tanzania. Analyzing 31 years of annual maximum rainfall data spanning from 1990 to 2020, the Gen-
eralized Extreme Value (GEV) model proved to be the best for modeling extreme rainfall in all stations. Tree estimation
methods–L-moments, maximum likelihood estimation (MLE), and Bayesian Markov chain Monte Carlo (MCMC)–were
employed to estimate GEV parameters and future return levels. Te Bayesian MCMC approach demonstrated superior per-
formance by incorporating noninformative priors to ensure that the prior information had minimal infuence on the analysis,
allowing the observed data to play a dominant role in shaping the posterior distribution. Furthermore, return levels for various
future periods were estimated, providing guidance for food protection measures and infrastructure design. Trend analysis using p
value, Kendall’s tau, and Sen’s slope indicated no statistically signifcant trends in rainfall patterns, although a weak positive trend
in extreme rainfall events was observed, suggesting a gradual and modest increase over time. Overall, the study contributes
valuable insights into extreme rainfall patterns and underscores the importance of L-moments in identifying the best ft dis-
tribution and Bayesian MCMC methodology for accurate parameter estimation and prediction, enabling effective measures and
infrastructure planning in the region.https://doi.org/10.1155/2024/853393
Influence of rice husk derived nano-silica on performance, emissions, and combustion characteristics of diesel engine fueled with baobab biodiesel
Get PDFA Dissertation Submitted in Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Sustainable Energy Sciences and Engineering of the Nelson Mandela African Institution of Science and TechnologyThe increasing number of on-road automobiles as a result of an exponential increase in
population and lifestyle places enormous strain on depleted fossil petroleum fuel, energy
security, and environmental stability. This situation drives researchers to find an alternative
source to replace petroleum diesel. Biodiesel is one of the promising viable substitutes.
However, biodiesels may not always fulfill the EN 14214 standard due to differences in fuel
properties. This could cause issues with engine operation and emissions. This study therefore
aims to use novel nano-silica (SiO2) additives extracted from rice husk to improve its fuel
properties. Also focuses on the influence of additives on the operation of the compression
ignition (CI) engine. The Adansonia digitata methyl esters (ADME) were made by
transesterification process, The physicochemical properties of the fuels with and without
additives were measured as per ASTM D6751 and EN 14214 standards methods, and nano silica was analyzed by Thermogravimetry (TGA), Fourier transform infrared spectroscopy
(FT-IR), Brunauer Emmett Teller (BET), X-ray diffractometer (XRD. Barret-Joyner Halenda
(BJH) pore diameter, specific surface area, and pore volume of SiO2 were observed to be 19.3
nm, 502.24 m2
/g, and 0.761 cm3
/g, respectively. At 400 and 800 ppm dose levels, the oxidation
induction period (OIP) increased dramatically, peaking at 10.03 h. The stability of
ADME has significantly improved, as evidenced by these results, meeting the >3 h and >8 h
standard limits set by ASTM D6751 and EN 14214, respectively. The viscosity of B100
decreased with increasing additive content, from 4.62 mm2
/s for neat B100 to 2.21 mm2
/s for
400 ppm. Cetane number (CN) (60 to 64). All nano-fuel blends used in engine tests were
prepared by an ultrasonication process. The results revealed that the brake thermal efficiency
(BTE) at maximum brake powers (BP) for B20, B20+SiO2, B100, and B100+SiO2 fuels were
29.9, 28.2, 28.44, and 27.1%, respectively, and brake-specific fuel consumption (BSFC) was
reduced as the load increased. The peak heat release rate (HRR) of the B100+SiO2 and
B20+SiO2 are slightly higher by 2.9 and 2.6%, respectively, than the neat B100 at medium BP.
However, in-cylinder gas pressure (CGP) increased following the order of
B20+SiO2<B20<B100<B100+ SiO2<B0. Moreover, the exhaust emissions of nano-fuel blends
exhibited a greater reduction of CO, THC, CO2, NOX, and particulate matter (PM) compared
to B20 and B100. Overall, this study recommends that SiO2 nano-additive is a good substitute
fuel additive to use with biodiesel and its blends because of the improved properties of
biodiesel, decreased emissions, and increased engine performance efficienc
Emerging pollution, antimicrobial resistance, and the applicability of biochar adsorbents: A comprehensive study in African water systems
Get PDFA Thesis Submitted in Fulfilment of the Requirements for the Award of the Degree of
Doctor of Philosophy in Environmental Science and Engineering of the Nelson Mandela
African Institution of Science and TechnologyThe impacts of antimicrobial resistance (AMR) extend far beyond clinical settings, permeating
into agriculture and the economy, precipitating dire consequences such as compromised
treatment efficacy, diminished agricultural productivity, and substantial economic burdens.
This study aimed at investigating the occurrences, composition and distribution of
antimicrobial pollutants and further study the remediation of lamivudine and ciprofloxacin
from synthetic solutions onto JS biochar using a response surface methodology (RSM) based
on optimal design. Results indicates identification of Klebsiella spp., Proteus spp.,
Pseudomonas aeruginosa, and Escherichia coli and were resistant to at least 1 of the tested
antibiotics, indicating their presence in wastewater and urban receiving waters. Higher
proportion of multi-drug resistance (MDR) in Escherichia coli,83%, than Klebsiella spp.,
68.5% and Pseudomonas aeruginosa, 20%. All bacterial species highly resisted penicillin (P),
while showed less resistance to gentamycin (CN). The isolates contained sulphonamide resistant genes (Sul 1 and Sul 2), tetracycline-resistant genes (Tet A, Tet B – 1, and Tet D) and
β-lactamases (bla CTX-M and bla SHV), and Escherichia coli harboured more MDR genes (39%),
followed by Klebsiella spp., 22%. JS biochar was amorphous, with porous, rough surface and
potential functional groups for adsorption of contaminants. Further, results indicate increase in
carbon content of JS biochar from 64.25-87.93 (wt.%) and nitrogen from 2-2.29 (wt.%) when
calcination temperature increased from 400℃ to 600℃, with highest surface area of 261.2
m2/g and adsorption capacity of 555.55 mg/g for ciprofloxacin and 400 mg/g for lamivudine.
Lamivudine removal had a model regression coefficient R2
, adjusted R2, and predicted R2 of 0.9934, 0.9761, and 0.8340, respectively. While for the ciprofloxacin model, the regression
coefficient R2, adjusted R2,and projected R2 were 0.9968, 0.9891, and 0.8023, respectively.
The maximum experimental removal efficiency of lamivudine and ciprofloxacin onto JS
biochar reached 84.9% and 94.46%, respectively. Isotherm data indicated lamivudine and
ciprofloxacin adsorption onto JS biochar followed the Freundlich isotherm. The study
identified antimicrobial residues as well as the presence of antibiotic resistant bacteria in water.
It also demonstrated the effectiveness of JS biochar adsorbent for remediation of lamivudine
and ciprofloxacin from synthetic water, indicating future improvement and use in mitigating
antimicrobial resistance
Land Use/Cover Classification of Large Conservation Areas Using a Ground-Linked High-Resolution Unmanned Aerial Vehicle
Get PDFthis research article was published by MDPI,2024High-resolution remote sensing platforms are crucial to map land use/cover (LULC) types. Unmanned aerial vehicle (UAV) technology has been widely used in the northern hemisphere, addressing the challenges facing low- to medium-resolution satellite platforms. This study establishes the scalability of Sentinel-2 LULC classification with ground-linked UAV orthoimages to large African ecosystems, particularly the Burunge Wildlife Management Area in Tanzania. It involved UAV flights in 19 ground-surveyed plots followed by upscaling orthoimages to a 10 m × 10 m resolution to guide Sentinel-2 LULC classification. The results were compared with unguided Sentinel-2 using the best classifier (random forest, RFC) compared to support vector machines (SVMs) and maximum likelihood classification (MLC). The guided classification approach, with an overall accuracy (OA) of 94% and a kappa coefficient (k) of 0.92, outperformed the unguided classification approach (OA = 90%; k = 0.87). It registered grasslands (55.2%) as a major vegetated class, followed by woodlands (7.6%) and shrublands (4.7%). The unguided approach registered grasslands (43.3%), followed by shrublands (27.4%) and woodlands (1.7%). Powerful ground-linked UAV-based training samples and RFC improved the performance. The area size, heterogeneity, pre-UAV flight ground data, and UAV-based woody plant encroachment detection contribute to the study’s novelty. The findings are useful in conservation planning and rangelands management. Thus, they are recommended for similar conservation areas.
Keywords:
community wildlife management areas; random forest algorithm; remote sensing technologies; Sentinel-2; pre-UAV flight ground data; unmanned aerial vehicle
Spatio-temporal variability in transmission risk of human schistosomes and animal trematodes in a seasonally desiccating East African landscape
Get PDFThis research article was published by Proceedings of the Royal Society B: Biological Sciences Volume 291, 2024Different populations of hosts and parasites experience distinct seasonality in environmental factors, depending on local-scale biotic and abiotic factors. This can lead to highly heterogeneous disease outcomes across host ranges. Variable seasonality characterizes urogenital schistosomiasis, a neglected tropical disease caused by parasitic trematodes (Schistosoma haematobium). Their intermediate hosts are aquatic Bulinus snails that are highly adapted to extreme rainfall seasonality, undergoing prolonged dormancy yearly. While Bulinus snails have a remarkable capacity for rebounding following dormancy, we investigated the extent to which parasite survival within snails is diminished. We conducted an investigation of seasonal snail schistosome dynamics in 109 ponds of variable ephemerality in Tanzania from August 2021 to July 2022. First, we found that ponds have two synchronized peaks of schistosome infection prevalence and observed cercariae, though of lower magnitude in the fully desiccating than non-desiccating ponds. Second, we evaluated total yearly schistosome prevalence across an ephemerality gradient, finding ponds with intermediate ephemerality to have the highest infection rates. We also investigated dynamics of non-schistosome trematodes, which lacked synonymity with schistosome patterns. We found peak schistosome transmission risk at intermediate pond ephemerality, thus the impacts of anticipated increases in landscape desiccation could result in increases or decreases in transmission risk with global change
Ecological consequences of microplastic pollution in sub-Saharan Africa aquatic ecosystems: An implication to environmental health
Get PDFThis research article was published by Elsevier HydroResearch Volume 7, 2024Microplastic pollution (MPs) emerged as a significant environmental concern due to its persistent nature. These MPs particles endure in waters, soils, and even the atmosphere, posing potential threats to the entire ecosystem. Aquatic organisms are at risk of ingesting MPs, leading to accumulation in tissues, ultimately affecting entire food chain. This study aims to provide an overview of sources of MPs, distribution, and potential environmental impacts. MPs have been documented in various substances such as bottled water, salts, seafood, and even the air. However, the full extent of the health consequences on human exposure remains uncertain. Therefore, it is imperative that we draw public attention to the presence of these pollutants in the environment. To mitigate adverse effects of MPs, reducing plastic consumption, implementing improved waste management practices, and advocating sustainable behaviors are essential for well-being of natural ecosystems and the health human populations