2647 research outputs found
Sort by
Mathematical models for the infectiology and cost-effectiveness of the control strategies for brucellosis
Get PDFA Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor
of Philosophy in Mathematical and Computer Sciences and Engineering of the Nelson
Mandela African Institution of Science and TechnologyBrucellosis is a contagious zoonotic infection caused by Gram-negative bacteria of family Bru cellaceae and genus Brucella that affects humans and animals. The disease is of economic sig nificance, veterinary interest and a public health concern in most developing countries. Direct
interaction among vulnerable and infectious animals or their tainted products represent the two
substantial pathways for the infection conveyance. This study aimed at developing and analyz ing deterministic mathematical models for the infectiology and cost-effectiveness of Brucellosis
control measures. The control mechanisms that were taken into consideration are vaccination of
livestock, culling of seropositive animals by slaughtering, personal protection, and proper en vironmental hygiene and sanitation. Both analytical and numerical simulations are presented.
Sensitivity analysis of the effective reproductive number revealed that the rates of livestock mor tality, recruitment, livestock to livestock transmission, vaccination and disease-driven culling
are the most sensitive parameters and should be targeted in designing of the control strategies
for the disease. Optimal control and cost-effectiveness analysis of the model disclosed that
merging of personal protection, environmental hygiene and sanitation, progressive slaughter ing of seropositive livestock, and livestock vaccination significantly reduces infection spread in
both humans and livestock at a lower cost. Additionally, seasonal weather variations have great
impact on Brucellosis transmission dynamics in human, livestock and wild animals. Therefore,
for the disease to be controlled or eradicated, this study recommends the timely implementation
of control measures pursuant to fluctuations in disease transmissio
Developing a context specific climate smart aquaculture framework for improving food security in Tanzania
Get PDFA Thesis Submitted in Partial Fulfilment of the Requirements for the Degree of
Doctor of Philosophy in Life Sciences of the Nelson Mandela African Institution of
Science and TechnologyAquaculture has great potential to improve global food and nutrition security. However, due to the
effect of climate changes and poor fish farming practices in some countries, it favors the
accumulation of chemicals and disease-causing pathogens including bacteria, viruses, and parasites.
This study, therefore, aimed to assess the adequacy of existing aquaculture practices and evaluated
the levels of heavy metals and the prevalence of parasites and bacteria pathogens. The information
was used to design a context-specific climate-smart fish pond and fish feed for improving fish
production in Tanzania. The study was conducted in Arusha and Morogoro regions, five sites from
each region were selected for the study. A total of 130 fish farmers each with one fish pond were
selected for interview and sample collection. The questionnaire was used to gather information on
the existing aquaculture management practices. Pond water, sediments, fish feed, and fish samples
were collected for the analysis of heavy metals, parasites, and bacteria pathogens. Polarized energy dispersive x-ray fluorescence spectrometer was used for heavy metal analysis, a microscope was
used to observe parasites present in fish samples, and analytical profile index test kits were used to
identify bacteria pathogens. The results showed that farmers lacked proper knowledge of
formulating high-quality fish feed and/or safe pond water management; these have a huge impact
on overall fish health and consumer safety. The most prevalent parasites in Arusha and Morogoro
were Acanthocephalus sp (49.2 & 50.7%) and Diplostomum sp (36.9 & 38. 4%). Aeromonas sobria
was the most prevalent fish bacteria found in Arusha (35.3%) and Morogoro (49.2%). Chromium
was the most accumulated heavy metal in the fish muscles sampled in Arusha (4.61 – 9.50 mg/kg)
and Morogoro (2.53 – 5.57 mg/kg). In this study, we designed and constructed a climate-smart pond.
The pond has the potential to support food security while reducing vulnerability to long-term climate
change impacts. Google Sheets Program was used to formulate a higher quality insect-based fish
feed. The quality and efficiency of the formulated feed were quantified by measuring growth
performance and feed utilization. Fish were observed to have growth improvement and feed
conversion efficiency throughout the experimental period. The use of the climate-smart fish pond
and formulated feed is recommended in improving fish production and ensuring consumer safety
Development of ta2o5 electrochemically reduced graphene oxide nanocomposite electochemical sensor for oxytetracycline detection in Milk
Get PDFA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of
Master’s in Life Sciences of the Nelson Mandela African Institution of Science and
TechnologyVarious kinds of antimicrobials are being used in the veterinary sector for therapeutic and
growth promotion purposes. Significant amounts of antimicrobial residues are released in the
milk and exert harmful effects such as allergic reactions, carcinogenicity, mutagenicity and
teratogenicity as well as disturbance of normal flora in the gastrointestinal tract. Thus,
quantification of these residues is crucial. A number of conventional detection methods that are
in application, which use chromatographic, immunological and spectroscopic techniques are
sensitive, selective and used for confirmatory test. However, most of them are costly, time
consuming, laborious and cannot provide onsite results. In addition, most of the rapid detection
tests in the market are qualitative and non-confirmatory. Hence, for quick, portable, sensitive
and cost effective detection of antimicrobials, novel detection tools are needed. In this study,
novel tantalum pentoxide-electrochemically reduced graphene oxide nanocomposites modified
glassy carbon electrode (Ta2O5-ErGO/GCE) was developed for the detection of oxytetracycline
in milk. The composition, structure and morphology of GO, Ta2O5, and Ta2O5-ErGO were
characterized by X-ray diffraction and scanning electron microscopy. Oxytetracycline
electrochemical behavior on the bare GCE, GO/GCE, ErGO/GCE, and Ta2O5-ErGO/GCE was
studied by cyclic voltammetry. The Ta2O5-ErGO/GCE showed 2 fold increased magnification
of the oxytetracycline oxidation signal in comparison to GCE, GO/GCE, ErGO/GCE electrodes.
Under the optimum conditions, the currents were proportional to the oxytetracycline
concentration in the 0.2 to 10 μM range with 0.095 μM as low detection limit. The preparation
of Ta2O5-ErGO/GCE in the current work provides an outlook for detecting ultra-trace
oxytetracycline in milk
Corruption dynamics in Tanzania: Modeling the effects of control strategies
Get PDFA Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of
Master’s in Mathematical and Computer Science and Engineering of the Nelson
Mandela African Institution of Science and TechnologyCorruption can be defined generally as taking bribes, forcing out benefit, receiving money or
gifts as favour in exchange for doing one’s job. Worldwide corruption is considered a problem
that affects many countries in the world currently. Individuals loses their rights, lower
community confidence in public authorities, termination of employment, absence of peace and
security and misallocation of resources. Despite various measures which have been taken by
different countries to control corruption, the problem still persists. The negative impacts of
corruption are well known; however, little has been done on mathematical modelling on
corruption, particularly the inclusion of mass education and religious teaching as a strategy for
controlling corruption spread. In this study, the mathematical model for the dynamics of
corruption in the absence and presence of these control measures are presented and analysed
to determine which parameter are very sensitive to the spread of corruption and how will these
control strategies help to reduce corruption. Most parameters used in this work are from
different literature and some were assumed. The next generation matrix method is used to
compute the basic and effective reproduction number which used to study the corruption
dynamics. Sensitivity analysis results shows that, parameters of mass education and religious
teaching are the most sensitive to the control of corruption. Also, stability analysis for
equilibrium states by linearization, Lyapunov function and use of the Lassalle’s invariance
principle was derived and the results shows that the corruption free equilibrium is locally and
globally asymptotically stable when 0 < 1 and endemic equilibrium is globally
asymptotically stable when 0 > 1. The model was simulated by using Runge-Kutta 4
th order
in MATLAB and the results depict that when mass education
and religious teaching
are
combined together as a control measures, corruption within the country is successfully
controlled in a short period of time. The study recommends to invest more in provision of mass
education to the citizens through creating general awareness to all and including it in education
curriculum from pre-primary to university as well as to use religious leaders to teach their
followers seriously about the impact of corruption. The numerical simulation results agreed
with the analytical results
Characterization and effectiveness determination of indigenous rhizobia nodulating lablab (lablab purpureus) in Babati district, Tanzania
Get PDFA Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of
Master’s in Life Sciences of the Nelson Mandela African Institution of Science and
TechnologyThe soil samples from fifteen villages which grow Lablab in Babati district were collected and
used for planting Lablab in experimental pot to trap indigenous rhizobia. At a flowering stage,
the plants were harvested and root nodules were collected for rhizobia isolation using Yeast
Extract Mannitol Agar (YEMA). Under aseptic conditions, twenty-two isolates were obtained
and characterized by morphological, biochemical and physiological characteristics.
Furthermore, PCR amplification of 16S rDNA and symbiotic effectiveness were also
evaluated. The results showed that, rhizobia were fast and slow growing in YEMA after 4 - 7
days of incubation. In YEMA with Congo red one isolates absorbed the color, while,
physiologically all isolates were alkaline tolerant, however susceptible to acidity and sodium
chloride above 3%. High diversity among isolates was observed in dendrogram at 70%
similarity level by forming two groups with seven clusters. Only 18 isolates out of 22 were
amplified. In testing symbiotic effectiveness, all 22 isolates induced nodules in Lablab,
interestingly some were effective than commercial inoculants. Most of isolates recorded
relative symbiotic effectiveness above 100, the highest was 193 for BR4. Isolates BR4, BR13,
BR16, BR5 and BR18 were effective than other isolates and commercial strains. The results
implied presence of diverse and effective indigenous rhizobia nodulating Lablab in Tanzania,
also highlights their potential to be used for inoculating Lablab instead of commercial
inoculants. To recommend characterization by sequencing to identify their genetic groups and
field effectiveness evaluation is needed in order to identify more effective isolates for
inoculants production
Plant competition as an ecosystem-based management tool for suppressing Parthenium hysterophorus in rangelands
Get PDFThis research article published by ElsevierAbstract
The exotic invasive plant pathenium hystephorus is invading rangelands in Africa while causing
negative effects on the biodiversity, environment, economy, and human and animal health because
eco-friendly control methods are lacking.
We conducted experiments to investigate the suppressive effects of forage legume plant species;
desmodium introtrum(Fabaceae),lablab purpureus (Fabaceae), and medicago sativa (Fabaceae) in
suppressing the growth of pathenium hystephorus
pathenium hystephorus growth was suppressed when grown with fodder plant species at high
density. However, the effect was mediated by the presence of lablab purpureus.
Our work highlights the importance of competitive native plant diversity and density in rangeland
management.
Moreover, this control method could be part of an integrated control toolkit being deployed in a
community-based approach in other countries
Allelopathic Effects of Sphaeranthus suaveolens on Seed Germination and Seedling Growth of Phaseolus vulgaris and Oryza sativa
Get PDFThis research article published by Hindawi, 2021Weeds with allelopathic effect have been reported to cause significant damage in agriculture particularly in smallholder farming
systems. ,is study assessed the allelopathic effects of different concentrations of crude extract of a noxious weed Sphaeranthus
suaveolens on seed germination and seedling growth of Phaseolus vulgaris and Oryza sativa by examining germination, seedling
height, and total chlorophyll content after seven and fourteen days of crude extract treatment, respectively. Results showed that
seed germination and seedling growth were significantly (p < 0.001) decreased with increase in concentration of crude extract,
signifying concentration dependency. Highest concentration (100%) of S. suaveolens crude extracts resulted in 90% and 100%
inhibition of P. vulgaris and O. sativa seed germination, respectively. Chlorophyll content, fresh weight, and root and shoot length
of both P. vulgaris and O. sativa were also significantly (p < 0.001) affected by highest concentration (100%) of S. suaveolens crude
extracts. Results from this study suggest that the extract of S. suaveolens contains water-soluble allelochemicals which significantly
reduce growth and productivity of P. vulgaris and O. sativa
A mobile application used for the implementation of home based care: a case study of COVID-19 in Uganda
Get PDFA Project Report Submitted in Partial Fulfilment of the Requirements for the Degree of Master of Science in Embedded and Mobile Systems of the Nelson Mandela African Institution of Science and TechnologyWith the outbreak of Coronavirus Disease 2019 (COVID-19) the health sector around the
world has been faced with many challenges. This has created a need for alternative methods
of offering treatment; and among them is Home Based Care (HBC). Home Based Care is a
health system where patients are offered treatment in their localities or homes. The main
objective under this project was to develop a mobile system application to facilitate and
support monitoring of patients in Home Based Care so as to handle pandemics like COVID 19, and at the same time meant to be used by Village Health Teams (VHTs) to capture
information from patients under treatment in their localities. The evolutionary prototyping
methodology was used to develop the application system. Furthermore, both qualitative and
quantitative data collection methods such as document review, interviews, observation
methods and questionnaires were used to collect data about this research project. At last, a
government Home Based Care application to facilitate the handling of pandemics like
COVID-19 was developed. It shows that majority of the respondents believe the system will
be able to reduce or solve the identified problem in this dissertation. Majority of the users
and those who got to use the application agree that the application is easy to use and navigate.
The respondents also expressed their confidence in the application’s ability to enable the
implementation of Home Based Care as an alternative to offering health care in situations of
pandemics like COVID 19. In this project, we carried out unit testing, integration testing,
and system testing and user acceptance testing as a means of carrying out software validation.
The developed application passed successively all of the tests meaning that the developed
application perform as it was expected. Based on the scope of this project, many of the
features were not included in this prototype. Some of the known future works will be to add
an admin account which will be managing the application. This account will be able to
oversee all the VHT Officer accounts and will also be able to monitor the patient’s progres
Spatio-Temporal Patterns of Increasing Illegal Livestock Grazing over Three Decades at Moyowosi Kigosi Game Reserve, Tanzania
Get PDFThis research article was published by MDPI, 2021The global increase of livestock has caused illegal intrusion of livestock into protected areas. Until now, hotspot areas of illegal grazing have rarely been mapped, long-term monitoring data are missing, and little is known about the drivers of illegal grazing. We localized hotspots of illegal grazing and identified factors that influenced spatio-temporal patterns of illegal grazing over three decades in the Moyowosi Kigosi Game Reserve (MKGR), Tanzania. We used questionnaires with local pastoralists (N = 159), georeferenced aerial survey data and ranger reports from 1990–2019 to understand the reasons for illegal grazing in the area. We found that hotspots of illegal grazing occurred initially within 0–20 km of the boundary (H (3) = 137, p < 0.001; (H (3) = 32, p < 0.001) and encroached further into the protected area with time (H (3) = 11.3, p = 0.010); (H (2) = 59.0, p < 0.001). Further, livestock herd sizes decreased with increasing distance from the boundary (R = −0.20, p = 0.020; R = −0.40, p = 0.010). Most interviewees (81%) claimed that they face challenges of reduced foraging land in the wet season, caused by increasing land used for cultivation, which drives them into the MKGR to feed their livestock. We conclude that there is spatio-temporal consistency in the illegal livestock intrusion over three decades, and hotspot areas are located along the boundary of the MKGR. We suggest focusing patrols at these hotspot areas, especially during the wet season, to use limited law enforcement resources effectively
Climate and anthropogenic footprints implications on the surface and groundwater dynamics on the southern slopes of Mount Kilimanjaro, Tanzania
Get PDFA Thesis Submitted in Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Hydrology and Water Resources Engineering of the Nelson Mandela African Institution of Science and TechnologyClimate and land use/cover changes impact water resources all over the world. This study
aimed at developing a conceptual understanding and management of the impacts of present
and future climate change and human activities on surface and groundwater resources on the
Kikafu-Weruweru-Karanga (KWK) watershed. The methodology includes simulation of the
present and prediction of the future hydrological fluxes and streamflow prediction under
changing climate and land use/cover. Calibration and validation of the hydrological model,
Soil and Water Assessment Tool (SWAT) showed satisfactory performance (Nash-Sutcliffe
Efficiency (NSE)) > 0.50). A total of 22 parameters were used, and Curve number for soil
moisture condition II, Baseflow alpha-factor, and average slope steepness were the most
sensitive parameters. Future climate data for two Representative Concentration Pathway
(RCPs) from Regional Atmospheric Climate Model -22T and Climate Limited Area
Modeling 4 models were used. Land use/cover (LULC) maps were generated by classifying
time-series (1996, 2006, and 2018) satellite images, selected spatial metrics were used to
predict the LULC changes for the next decade using 2018 as a base year. Furthermore, the
implications of selected staple crops production over the next decade was predicted.
Simulated LULC shows expansion in built-up (by 32.55% and agriculture (by 39.52%) areas
from 2018 to 2030, and the forest area is projected to shrink by 6.37%. However, the results
suggest that farm size plays a minor role in increasing crop production. Expansion in
cultivation land and built-up area attributed to the changes in water yield, surface runoff,
evapotranspiration (ET), and groundwater flow. Rock-water interaction chiefly controls the
groundwater quality in the presence of HCO3 enrichment and mixed CaNaHCO3 water types.
The δ2H and δ18O values confirmed that recycled water is the primary recharge means, and
glacier melts on Mt. Kilimanjaro sustains downstream water availability during the dry
season. Furthermore, temperatures were projected to increase by 0.2ºC/year, and a decrease
in precipitation was projected up to 2100 in both highland and lowland areas. The findings
suggested the need to intensify the production per unit area rather than expanding the farm
size. Also, improving the vegetation cover on the hillside and abandoned land area could help
to reduce the direct surface runoff, and floods recurring in the area. The findings of this study
are useful to facilitate sustainable water resources management in the watershed and other
watersheds with or without modification