2647 research outputs found
Sort by
First Report of the Co-occurrence of Cylindrospermopsin, Nodularin and Microcystins in the Freshwaters of Lake Victoria, Tanzania
Get PDFThis research article published by Springer Nature Switzerland AG., 2020There is a global concern regarding the increase of cyanotoxins in freshwater and their potential effects on human health. The existence of multiple toxins in freshwater can result in an increased risk of their bioaccumulation in humans from their ingestion through contaminated drinking water or recreational activities. This study, the first of its kind, was conducted to determine the occurrence of thirteen cyanotoxins namely; microcystins (-LA, -LF, -LR, -LY, -LW, -RR, -YR, -WR, dm MC-RR and dm MC-LR), anatoxin-a, nodularin and cylindrospermopsin in the freshwaters of Lake Victoria in Tanzania. A total of 23 sites were selected for water sampling. Samples were randomly collected from lakeshores (n = 54), wells (n = 66) and piped water (n = 18) in two phases, February (dry season) and December (rainy season) 2018. Samples (n = 138) were analysed using liquid chromatography mass spectrometry (UPLC-MS/MS). Cylindrospermopsin was the most abundant cyanotoxin detected in the lakeshores, with eight of the nine collection sites (89%) reporting cylindrospermopsin in phase I, compared to three out of nine (33%) in phase II. Microcystin congeners -RR, -LR and -YR were detected in phase I, with microcystins -RR and -LR detected in phase II. MC concentrations ranged from 0.003 to 0.007 μg/L for MC-RR, 0.01–0.013 μg/L for MC-LR and 0.004 to 0.01 μg/L for cylindrospermopsin, with nodularin reported once at a concentration of 0.01 μg/L. No cyanotoxins were detected in wells or in treated pipe water samples. The existence of multiple toxins in different collection sites may lead to synergistic effects and increase the toxicological risk to humans. This is the first study to report the presence of cylindrospermopsin and nodularin in the freshwaters of Lake Victoria
Desirable Dog-Rabies Control Methods in an Urban setting in Africa - a Mathematical Model
Get PDFThis research article published by Modern Education and Computer Science Press, 2020Rabies is a fatal, zoonotic, viral disease that causes an acute inflammation of the brain in humans and other
mammals. It is transmitted through contact with bodily fluids of infected mammals, usually via bites or
scratches. In this paper, we formulate a deterministic model which measures the effects of different rabies
control methods (mass-culling and vaccination of dogs) for urban areas near wildlife, using the Arusha region
in Tanzania as an example. Values for various parameters were deduced from five years’ worth of survey data
on Arusha’s dog population. Data included vaccination coverage, dog bites and rabies deaths recorded by a
local non-governmental organization and the Ministry of Agriculture, Livestock Development and Fisheries of
the United Republic of Tanzania. The basic reproduction number R0 and effective reproduction number Re
were computed and found to be 1.9 and 1.2 respectively. These imply that the disease is endemic in Arusha.
The numerical simulation of the reproduction number shows that vaccination is the most appropriate control
method for rabies transmission in urban areas near wildlife reservoirs. The disease free equilibrium ε0 is also
computed. If the effective reproduction number Re is computed and found to be less than 1, it implies that it is
globally asymptotically stable in the feasible region Φ. If Re > 1 it is implied that there is one equilibrium
point which is endemic and it is locally asymptotically stable
Insulin-delivery methods for children and adolescents with type 1 diabetes
Get PDFThis research article published by SAGE Publications Ltd., 2020Efforts directed toward restoring normal metabolic levels by mimicking the
physiological insulin secretion, thereby ensuring safety, efficacy, minimal invasiveness and
conveniences, are of great significance in the management of type 1 diabetes among children
and adolescents. Regardless of the various technologies being discovered in addressing
invasiveness and enhancing medication adherence in the management of type 1 diabetes,
yet limited success had been observed among children and adolescents. The multiple daily
subcutaneous insulin injections route using vial and syringe, and occasionally insulin pens,
remain the most predictable route for insulin administration among children and adolescents.
However, this route has been associated with compromised patient compliance, fear of
injections and unacceptability, resulting in poor glycemic control, which promote the demand
for alternative routes of insulin administration. Alternative routes for delivering insulin are
being investigated in children and adolescents with type 1 diabetes; these include the hybrid
closed-loop ‘artificial pancreas’ system, oral, inhalation, intranasal routes, and others. This
review article explores the current advances in insulin-delivery methods that address the
needs of children and adolescents in the treatment of type 1 diabetes
Machine learning models for predicting decisions to be made by small scale dairy farmers in Eastern Africa
Get PDFA Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of
Doctor of Philosophy in Information and Communication Science and Engineering of
the Nelson Mandela African Institution of Science and TechnologyIn dairy, lack of decision support tools for identifying farmers' needs and demands have caused
many programs, strategies, and projects to fail. This has led to the inefficient and fragmented
allocation of scarce development resources. This study demonstrated how machine learning
(ML) can be used as a tool to bridge this gap; by developing ML models to be used in
identifying factors that can influence farmers decisions, predicting decision to be made by a
farmer and forecast on farmers demands regarding to their specific need or service. Four
countries: Ethiopia, Kenya, Tanzania and Uganda were selected for this study.
In the course of the study four models were developed one for each country with regard to
the usage of animal supplements, keeping of exotic animals, use of Artificial insemination (AI)
as breeding methods and animal milk productivity. Data was collected through face to face
interviews, from a total of 16 308 small scale dairy farmers in Ethiopia (n = 4679), Kenya (n =
5278), Tanzania (3500) and Uganda (n = 2851). The decision tree algorithm was used to model
categorical problems (use of supplement and breeding decision), which attained the accuracy
of 78%-90%. Moreover, K-nearest neighbor was employed for numeric problems (keeping of
exotic animals and animal milk productivity) with an accuracy of 0.78-0.96 Adjusted R
The use of ML techniques assisted in classifying farmers based on their characteristics and it
was possible to identify the key factors that can be taken then prioritized to improve the dairy
sector among countries. Also, the results of this study offer a number of practical implications
for the dairy industry where the proposed ML models can enable decision-makers in
developing the National Dairy Master Plan and design policies that promote the growth of
smallholder dairy farming. Moreover, these models shade light to potential service providers
and investors who want to invest in dairy to identify potential areas or groups of farmers to
focus with.
2
value
Assessment of groundwater abstraction and hydrogeochemical investigation in Arusha city, northern Tanzania
Get PDFA Dissertation Submitted in Partial Fulfilment 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 TechnologyIn this work geological and hydrogeochemical data, radioisotopes and stable isotopes, and
groundwater hydrographs were used to assess the groundwater abstraction trends and
hydrogeochemical characteristics of Arusha wellfield in Arusha city. Groundwater salinity in
terms of conductivity (EC) was also used to delineate salinity occurrence and distribution in
different parts of Tanzania including Arusha where this study was carried out. The
hydrogeochemical results revealed Na-K-HCO
3
water type. Water-rock interaction seems to
be the main process determining the groundwater chemistry in the study area. The analysis
of geological sections showed two potential aquifers, volcanic sediment and
weathered/fractured both of which yield water with high fluoride. Eighty two (82) percent of
the analyzed groundwater samples indicated fluoride concentrations higher than WHO
guidelines and Tanzanian drinking water standards (1.5 mg/l). Groundwater hydrographs
indicated significant groundwater depletion. Water level decline of about 1.0 m/year and
discharges reduction of 10 to 57% were observed from the year 2000 to 2017. The
radiocarbon isotope signatures showed that groundwater with mean age of 1400 years BP to
modern was being abstracted from the wellfield. Recently recharged water was also
evidenced by high
14
C activities (98.1±7.9 pMC) observed in spring water. Both groundwater
hydrographs and isotope signatures suggest that the Arusha wellfield is already stressed due
to groundwater over-abstraction. Through groundwater salinity mapping, it was revealed that
generally Arusha has fresh groundwater but with relatively high electric conductivity (10002000
µS/cm). The high salinity levels are partly due to dissolution of trona (evaporate
mineral) commonly found in the East African Rift System. It was further revealed that lack of
reliable hydrogeological information including interaction between surface water and
groundwater hinders water resources management efforts particularly issuance of water use
permit. Based on the findings of this study, it is recommended to carry out groundwater flow
patterns modelling to show how unregulated drilling affects the deep wells currently
depletion problem
Development of a Natural Product Rich in Bioavailable Omega-3 DHA from Locally Available Ingredients for Prevention of Nutrition Related Mental Illnesses.
Get PDFThis research article published by Taylor & Francis Online, 2020Poor mental health remains a serious public concern worldwide. The most vulnerable individuals are children and adolescents in developing countries. Nutritional deficiency of long-chain omega-3 fatty acids, particularly docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), have long been recognized as a major contributing factor for mental health illnesses. Provision of ready-to-use natural product rich in preformed Omega-3 DHA and EPA could address this problem. However, most commonly used products are expensive and contain less or no preformed Omega-3 DHA and EPA, making them less suitable for prevention of mental illnesses in resource-poor countries. The main objective of this study was to develop a natural product rich in preformed Omega-3 DHA and EPA from locally available ingredients. Linear programing (LP) was used to formulate a natural product rich in preformed Omega-3 DHA and other essential nutrients using locally available ingredients other than fish and dairy products. Laboratory analysis was then performed to validate the nutritional value of the LP-formulation using standard analytical methods. The relative difference between the LP tool calculated values, and the laboratory-analyzed values were calculated. Sensory testing was also done to evaluate consumer acceptance of the final product. Optimal formulation contained about 220 mg of preformed Omega-3 DHA + EPA, enough to meet the RDI for children aged 2-10 years. The LP analysis further showed that the cost of the developed product is USD 0.15/100 g, which is 50% lower than that of Plumpy'nut. Laboratory analysis revealed similar results as that of LP at P = 0.05. These findings indicate that ready-to-use natural food rich in preformed DHA and EPA can be developed from locally available ingredients
Development of secured algorithm to enhance the privacy and security template of biometric technology
Get PDFA Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of
Doctor of Philosophy in Mathematical and Computer Science and Engineering
of the Nelson Mandela African Institution of Science and TechnologyThe security of information and personal privacy are the growing concerns in today’s human
life worldwide. The storage of biometric data in the database has raised the prospect of
compromising the database leading to grave risks and misuse of the person’s privacy such as
growth in terrorism and identity fraud. When a person’s biometric data stored is revealed,
their security and privacy are being compromised. This research described a detailed
evaluation on several outbreaks and threats associated with the biometric technology. It
analyzed the user’s fear and intimidations to the biometric technology alongside the
protection steps for securing the biometric data template in the database. It is known that,
when somebody’s biometric data template is compromised from the database that
consequently might indicate proof of identity robbery of that person. Mixed method to
compute and articulate the results as well as a new tactic of encryption-decryption algorithm
with a design pattern of Model View Template (MVT) are used for securing the biometric
data template in the database. The model managed information logically, the view indicated
the visualization of the data, and the template directed the data migration into pattern object.
Factors influencing fear of biometric technology such as an exposer of personal information,
improper data transfer, and data misuse are found. Strong knowledge of the ideal technology
like the private skills of the biometric technology, data secrecy and perceived helpfulness are
established. The fears and attacks along the technology like a counterfeit of documents and
brute-force attack are known. The designed algorithm based on the cryptographic module of
the Fernet keys instance are utilized. The Fernet keys are combined to generate a multiFernet
key, integrated with biometric data to produce two encrypted files (byte and text file). These
files are incorporated with Twilio message and firmly stored in the database. The storage
database has security measures that guard against an impostor’s attack. The database system
can block the attacker from unauthorized access. Thus, significantly increased individual data
privacy and integrity
Purchasing and up-scaling of the privatized advisory services: An innovation perspective on privatized soil testing in Africa
Get PDFThis research article published by Taylor & Francis Online, 2020As the trend of privatizing agricultural advisory services grows in developing countries, the need for the systematic thinking in innovation development is of interest for private companies that are trying to introduce various technologies in the agriculture sector. We explored the factors that affect the purchasing and upscaling of the privatized agricultural advisory services. We used a mobile soil testing service offered by a private company in Kenya as a case study. Additionally, we conducted minor explorations in Ethiopia, Ghana, and Tanzania. Our study found out that, while the service with its financial arrangement seems to be accepted by farmers, the social organization of system institutions is complex because not only technical factors but also social factors influenced adoption of the service. The study is an exemplifying case of the relevance of modeling innovations as complex configurations in a dynamic system of diverse actors in a community
Optimization of domestic biogas stove burner for efficient energy utilization
Get PDFA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of
Master’s in Sustainable Energy Science and Engineering of the Nelson Mandela
African Institution of Science and TechnologyThe inefficient indoor burning of fuel wood on traditional cook stoves generates pollutants,
primarily carbon monoxide and many other human health-damaging emissions. It is from this
risk that it is necessary to have an immediate shift to alternative cleaner fuel sources. Biogas,
which is among the biofuels from biomass, is one of the resources that play a considerable
part in a more diverse and sustainable global energy mix. For domestic purposes in rural
areas of Tanzania, biogas provides a better option that can supplement the use of fossil fuels
such as wood, charcoal, and kerosene, which is nonrenewable. However, the low efficiency
experienced in the locally made biogas burners hinders the large-scale use of biogas amongst
the population in the country. With the locally made burners, the users of biogas for the
domestic application face problems including heat loss and high gas consumption which
affects the whole cooking process. It is against this backdrop that the current study objectives
incline on designing and improving the efficiency of the locally manufactured burners to
achieve the uniform flow of fuel in the mixing chamber, which will result to the consistent
heat distribution around the cooking pot. The optimization of the burner was done by using
computational fluid dynamics (CFD) through varying the number of flame portholes, air
holes as well as the size of the jet before fabrication. The increased efficiency of the burner
has also contributed by the addition of the fuel distributor. The results showed that the
optimum hole diameter of the jet was 2.5 mm and that of the manifold was 100 mm. The
currently developed biogas burner was tested and compared with the other two locally made
burners. The water boiling test (WBT) on these three burners showed that the developed
burner has a thermal efficiency of 67.01% against 54.61% and 58.82% of Centre for
Agricultural Mechanization and Rural Technology (CARMATEC) and Simgas respectively.
Additionally, the fuel consumption of the developed burner was 736 g/L as compared to 920
g/L for CARMARTEC and 833 g/L for that of Simgas. The developed burner and its
corresponding cook stove are both environmentally friendly and economical for household
utilization in Tanzania and other developing countries
Thermal Performance Analysis of Solar Dryer Integrated with Heat Energy Storage System and a Low-Cost Parabolic Solar Dish Concentrator for Food Preservation
Get PDFThis research article was published by journal of energy,Volume,in 2020Solar energy has become a viable alternative energy because it is a clean type of energy that converts solar radiation into heat energy for various applications such as heating water, power generation, cooking, and food drying. The solar dryer, integrated with the heat energy storage system, uses nitrate salt as a heat storage medium which was designed and tested by drying 1000 grams of red pepper at 19.6 to 62.4°C. The average ambient temperature ranged from 19.3 to 37.4°C, and the maximum temperature of the heat storage media ranged from 87.8 to 125°C. The solar drying process was compared to open sun drying system loaded with 1000 grams of red pepper. The findings showed that the solar dryer maintained color and flavor and lowered the original moisture content from 86% to 10% for 24 hours compared to 36 hours of drying in open air. In this study, nitrate salt is shown to be the perfect heat storage medium for drying food products; it preserved heat for about 4 hours when there is no active sunlight