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High-frequency dynamics of pH, dissolved oxygen, and temperature in the coastal ecosystems of the Tanga- Pemba Seascape: implications for upwelling-enhanced ocean acidification and deoxygenation
Get PDFThis article published by Frontiers in Marine Science,2024Ocean acidification, deoxygenation, and warming are three interconnected
global change challenges caused by increased anthropogenic carbon
emissions. These issues present substantial threats to marine organisms,
ecosystems, and the survival of coastal communities depending on these
ecosystems. Coastal upwelling areas may experience significant declines in
pH, dissolved oxygen (DO), and temperature levels during upwelling events,
making marine organisms and ecosystems in these areas more susceptible to
ocean acidification and deoxygenation. Understanding the dynamics of pH,
DO, and temperature in coastal upwelling areas is essential for evaluating the
susceptibility of resident organisms and ecosystems to lower pH and DO
conditions occurring during upwelling events. To accomplish this, we used
the pH and the DO loggers to measure high-frequency data for pH and DO,
respectively, over six months in the open ocean and for a 24-hour cycle
within the mangrove, seagrass, and coral reef ecosystems of the Tanga-
Pemba Seascape (T-PS) during the northeast monsoon season. Our findings
revealed the occurrence of multiple upwelling events, with varying durations,
that result in significant declines in pH, DO, and temperature within the
seascape. This is the first study to confirm the occurrence of multiple
upwelling events in the T-PS. Moreover, the study has revealed a pH
threshold value of 7.43 for ocean acidification in the T-PS. This is the first
study to report a threshold value for ocean acidification in coastal upwelling
areas of the Western Indian Ocean (WIO). Furthermore, it revealed that the
extremely low levels of pH that occurred during upwelling events were above
the pH threshold value of 7.43 for ocean acidification, while the extremely
low levels of DO fell below the oxygen threshold value of 4.6 mg/L for
deoxygenation. During upwelling events, seagrass and coral reef ecosystems,but not mangrove ecosystems, demonstrated elevated mean hourly values of
pH and DO compared to those of the open ocean. These findings show that
marine organisms and ecosystems in the T-PS are frequently exposed to
lower pH and DO conditions due multiple upwelling events. However, their
susceptibility to these conditions is reduced to some extent by the presence
of seagrass meadows within these interconnected systems
The removal of arsenic from synthetic solution using a sand filter coupled with zero valent iron
Get PDFA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science in Environmental Science and Engineering of the Nelson Mandela African Institution of Science and TechnologyContamination of groundwater with arsenic (As) poses a serious risk to public health,
demanding the development of effective remediation technology. This study investigated the
use of sand filters coupled with of zero-valent iron (ZVI) for removal of arsenic from
synthetic solutions as the function of ZVI dosage and contact time. ZVI materials, including
iron wool, iron fillings, and iron nails, were investigated and compared for their efficacy in
removing As from synthetic solutions. The experiment employed synthetic solutions spiked
with As compounds (set to be 1000 µg/L) to simulate contaminated groundwater scenarios.
The concentrations of As in the influent and effluent samples were used to calculate the
efficiency. The findings indicate that all three forms of ZVI tested exhibited significant As
removal capabilities. Iron wool, iron fillings, and iron nails demonstrated varying
efficiencies, likely influenced by their surface area, reactivity, and specific surface chemistry.
According to the findings, iron wool-containing sand filter was more effective at removing
As than iron filings and iron nails. As removal efficiency increased with increase in ZVI
dose. The results show that As can effectively be removed from water in the first 48h. The
highest removal efficiency was 99.6% and the lowest removal efficiency was 82.7%. These
results suggest that ZVI materials could be promising candidates for practical applications in
As-contaminated groundwater treatment systems. This study contributes valuable insights
into the use of inexpensive and widely available ZVI materials for As remediation,
highlighting their potential as sustainable solutions for addressing water quality challenges
Genomic characterization of methicillin-resistant Staphylococcus aureus isolated from patients attending regional referral hospitals in Tanzania
Get PDFThis research article was published by BMC Medical Genomics ,Volume 17, (2024)Background
Methicillin-resistant Staphylococcus aureus (MRSA) colonization increases the risk of subsequent infection by MRSA strain complex interlinking between hospital and community-acquired MRSA which increases the chance of drug resistance and severity of the disease.
Objective
Genomic characterization of Staphylococcus aures strains isolated from patients attending regional referral hospitals in Tanzania.
Methodology
A laboratory-based cross-sectional study using short read-based sequencing technology, (Nextseq550,Illumina, Inc. San diego, California, USA). The samples used were collected from patients attending selected regional referral hospitals in Tanzania under the SeqAfrica project. Sequences were analyzed using tools available in the center for genomic and epidemiology server, and visualization of the phylogenetic tree was performed in ITOL 6.0. SPSS 28.0 was used for statistical analysis.
Results
Among 103 sequences of S. aureus, 48.5% (50/103) carry the mecA gene for MRSA. High proportions of MRSA were observed among participants aged between 18 and 34 years (52.4%), in females (54.3%), and among outpatients (60.5%). The majority of observed MRSA carried plasmids rep5a (92.0%), rep16 (90.0%), rep7c (90.0%), rep15 (82.0%), rep19 (80.0%) and rep10 (72.0%). Among all plasmids observed rep5a, rep16, rep20, and repUS70 carried the blaZ gene, rep10 carried the erm(C) gene and rep7a carried the tet(K) gene. MLST and phylogeny analysis reveal high diversity among MRSA. Six different clones were observed circulating at selected regional hospitals and MRSA with ST8 was dominant.
Conclusion
The study reveals a significant presence of MRSA in Staphylococcus aureus strains from Tanzanian regional hospitals, with nearly half carrying the mecA gene. MRSA is notably prevalent among young adults, females, and outpatients, showing high genetic diversity and dominance of ST8. Various plasmids carrying resistance genes indicate a complex resistance profile, highlighting the need for targeted interventions to manage MRSA infections in Tanzania
The interplay between historical land-use and the distribution of Helichrysum shrubs in an African-protected grassland
Get PDFThis research article was published by African Journal of Ecology Volume 62, 2024Human land use can have lasting impacts on landscape characteristic, yet there remains a lack of information on how former land use affects plant communities in protected African grasslands. In this study, we investigated how land uses prior to the creation of Kitulo National Park, Tanzania, shaped the presence and abundance of the native shrub, Helichrysum species. We evaluated both plant species composition and soil properties across the park by dividing our sample into three different zones of historical land use based on participatory mapping. We divided the park into three former land uses: (1) livestock grazed and cultivated; (2) grazed only and (3) wild grazing with limited human impact. We observed that former grazed cultivated land use had five times higher Helichrysum abundance than former ‘wild’ land use. Soil pH, magnesium and phosphorus levels varied significantly across zones of historical land use but not between sites with and without Helichrysum species. Helichrysum splendidum was more abundant in soils with low soil phosphorus and magnesium concentrations. Our study demonstrates that historic grazing and cropping land uses through changes in soil nutrient properties can explain current Helichrysum species spread in protected areas. As such, conservation management plans would benefit from integrating mapping of former land uses to target interventions for problematic encroaching shrubs
Fluoride and pathogens removal from water using combined electrocoagulation-inline-electrolytic disinfection process
Get PDFA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Master’s in Environmental Science and Engineering of the Nelson Mandela African Institution of Science and TechnologyThe consecutive removal of fluoride (defluoridation) and pathogens (disinfection) in drinking
water through combined electrocoagulation-inline-electrolytic disinfection (EC–ECl2) process
with aluminum and dimension-stable mixed oxide electrodes was reported in this study.
Laboratory trials have been conducted on the effects of flow rate, initial pH, current density, and
supporting electrolytes for defluoridation and disinfection processes. The results have shown that
with a flow rate of 10 L/h, initial pH of 6, the current density of 9.4 mA/cm2 (EC cell) and 3.1
mA/cm2 (ECl2 cell), supporting electrolyte concentration of 165 mg/L, and electrolysis time of 50
min, a defluoridation rate of 88% (initial concentration of 12.3 mg/L) and complete disinfection
(initial fecal coliforms of 19,700 colony-forming units per 100 mL (CFU/100 mL)) can be reached.
The final concentration of fluoride and pathogens in treated water was 1.44 mg/L and 0 CFU/100
mL, which are within the acceptable limit of the World Health Organization and the Tanzania
Bureau of Standards of 1.5 mg/L and 0 CFU/100 mL, respectively. The EC–ECl2 system is a
promising approach for consecutive defluoridation and disinfection of water to save millions from
fluorosis and waterborne diseases. However, optimization potential with regard to energy
efficiency and system complexity were identified
Development of data-driven web-based system for regional programme accreditation: a case study of the inter-university council for East Africa (IUCEA)
Get PDFIn response to evolving regional program accreditation requirements, a user-centric Regional
Program Accreditation System (RPAS) was meticulously designed to cater to the diverse needs
of accreditation bodies, educational institutions, and expert reviewers. The development
journey commenced with an extensive requirement-gathering phase, engaging end-users to
shape the system's design and functionality. RPAS was built using cutting-edge technologies,
including ReactJs, Django, API integration, Tailwind CSS, and MySQL, ensuring scalability,
security, and flexibility. Agile methodologies, particularly Extreme Programming (XP), were
embraced, enabling expedited development and fostering close collaboration, ensuring
adaptability to users' evolving needs. The RPAS streamlines the accreditation process with a
user-friendly interface and real-time collaboration features, thereby enhancing transparency
and operational efficiency. To guarantee data security, reliable authentication procedures to
guarantee data security, reliable authentication procedures have been implemented. Additional
user-friendly features, such as night mode, QR code-based certificate verification, and
automated notifications, were introduced for convenience. The project prioritized user training
and support, data privacy, and seamless user feedback integration to make RPAS an intuitive
and responsive tool. It is noteworthy that the Rasch model was utilized in the development of
a similar system, but its application was limited to primary and secondary schools in Indonesia.
These enhancements further empower RPAS, making it a valuable tool for streamlining
accreditation processes and contributing to the elevation of program quality and educational
excellence in the region. The RPAS represents a significant advancement in the accreditation
landscape, offering an integrated, user-centric solution that addresses the unique needs of all
stakeholders involved in the accreditation process. Its potential for further improvements
makes it a promising instrument for the future of educational quality assurance in the region
Mathematical Models for Chikungunya Virus: Effects of Heterogeneity and Periodic Environmental Variations
Get PDFIn recent years, chikungunya, a mosquito-borne viral disease has spread globally and invaded new habitats and, as such, it is now regarded as one of the global threats to humanity because of its highly debilitating nature and unprecedented magnitude of its spread. Precisely, there is inadequate mechanistic understanding of how environmental factors, socioeconomic factors and disease intervention strategies, combined, affects epidemic magnitude and duration. In this study, we developed four mechanistic models for Aedes aegypti mosquitoes and chikungunya virus transmission that incorporates relevant ecological and biological factors, socio-economic factors and disease intervention strategies. The first model quantifies the effects of biological control and temperature on the growth of Aedes aegypti mosquito population in the environment. Utilising empirically derived temperature functions in literature, we observed that temperature ranges from 29^0 C to 35^0 C supports maximum egg hatching as well as development of larva and pupa. We also computed the vector reproduction number and examined the influence of entomological parameters on its magnitude. In addition, results also revealed that the attack rate of aquatic predators has higher impact to reduce mosquito population compared to the size of the predator population in the environment. In the second model, we developed a mathematical model to determine optimum timing of rolling out intervention strategies during a chikungunya virus outbreak. The proposed model incorporates three intervention strategies, physical barriers, larvicide and insecticide. Making use of optimal control theory, parameter sensitivity analysis, and numerical simulations, we performed a cost-effective analysis of the aforementioned intervention strategies. Findings from the proposed model offer a framework for designing cost-effective strategies for chikungunya with multiple intervention methods. Temperature and heterogeneous biting exposure are known to be integral factor capable of altering the spread of chikungunya during an outbreak. To quantify the role of these factors, we developed two mechanistic models, an autonomous and a non-autonomous. In a non-autonomous model temperature varies with time while in the autonomous it is regarded to be constant. In all scenarios, analysis of the model showed that both temperature and heterogeneous biting exposure have a substantial influence on shaping the transmission of the disease during an outbreak. Besides, temperature and heterogeneous biting exposure, the non-autonomous model incorporated mass media campaigns. Upon evaluating the implications of mass media campaigns during chikungunya outbreak, we observed that if 20% of infections are detected and reported, with mass media campaigns at 90% efficient, then the new infections produced may decrease by 68.8% over a four-year period. Overall, our results showed that temperature, predation, heterogeneous biting exposure and mass media campaigns play an essential component in determining both the short and long chikungunya virus dynamics
A hyperspectral-based system for identification of common bean genotypes resistant to foliar diseases in Tanzania
Get PDFCommon bean is one of many legumes (family Fabaceae) widely cultivated for their edible
seeds, seedpods, and leaves. Despite its benefits and life dependency especially in sub-Saharan
Africa, foliar diseases are causing a loss of 20% to 80% of common bean production, and the
development of improved common bean seeds resilient to those foliar diseases is still an issue
where among the major problem that the bean breeders are facing is manual phenotyping; a
slow field process and prone to errors as it depends on the eyes of the viewer. According to
the literature, imaging technologies have been introduced to help in different processes for
crops and disease management. However, there is a lack of automated mechanisms for
phenotyping processes to help breeders in trait data collection, disease scare classification, and
analysis of all data collected to identify resilient genotypes digitally. Among existing solutions,
there is still also a gap in plant health monitoring during all its growing stages needed by
breeders. Therefore, this study developed a unique hyperspectral data-based approach for
identifying bean genotypes resistant to foliar diseases and plant health monitoring. Using the
Random Forest classifier this study proved the genotype classification in three main breeding
categories; Resistant, Medium, and Susceptible. The experiment was conducted in four
Regions of Tanzania and three classifiers “Random Forest, XgBoost, and four layers Neuro
Network algorithms” were trained and tested with results of 0.96, 0.95, and 0.92 respectively.
The model was deployed on the cloud server where it is linked to a web application for easy
classification and data analysis. Applying different vegetation indexes including the
Chlorophyll Index, Photochemical Reflectance Index, Water Band Index, Modified
Chlorophyll Absorption in Reflectance Index, Nitrogen Reflectance Index, Structure
Insensitive Pigment Index, and Simple Ratio efficiently proved to be used for plant health
insight before disease symptoms are seen. This saves breeders time, reduces errors, and helps
them with digital phenotypic data, faster analysis, and easy storage for future references
Research progress of sodium super ionic conductor electrode materials for capacitive deionization
Get PDFThis research article was published by Separation and Purification Technology Volume 340, 15 July 2024The world is suffering from water shortage and the hope relies on the desalination of salty water. Several technologies are available for desalination such as reverse osmosis and electrodialysis. However, the application of these technologies in desalination is limited by the higher energy consumption, high investment and maintenance costs. Capacitive deionization (CDI), an up-coming technology at an infant stage is able to supplement the dwindling freshwater resources and provide water to the population. The performance of CDI is directly affected by the electrode materials. Since its inception carbon has been the principal electrode materials for CDI technology. However, low salt removal capacity due to inaccessibility of nanopores and ejection of co-ions hinder the application of carbon materials. Battery materials have been developed as an alternative to accompany carbon materials. Specifically, sodium superionic conductor (NASICON) materials have been used in brackish water desalination by CDI due to having the diffusion channels forming a three dimensional open structure and availability at low cost. However, the NASICON materials have not yet applied in the desalination of water with high salinity such as sea water. This paper reviews the present status of NASICON materials as CDI electrode materials and fairly compares it with carbon materials. It further compares the cost of NASICON and carbon materials, highlights the possibility of NASICON to desalinate high ionic strength solutions such as seawater. Moreover, the paper, discuss the methods which can be used to enhance the salt removal capacity of NASICON materials and provide examples of NASICON materials in the field of energy storage that can be borrowed and used in CDI. From the analysis of this work, NASICON materials are great companion of the carbon materials, are cost effective and are promising for the desalination of sea water
Variability in body weight and morphology of Uganda’s indigenous goat breeds across agroecological zones
Get PDFA research article was published by PLoS ONE volume 19,2024Indigenous goat breeds in Uganda are classified based on average body size parameters
and coat color. However, variations in the body size of animals may be influenced by several
factors, including management and the environment. To understand the effect of the agro-
ecological zone on the physical characteristics and live weight of Uganda’s indigenous
goats, this study evaluated the body size characteristics of the three indigenous goat breeds
of Uganda across ten agroecological zones. The cross-sectional survey was conducted in
323 households from the ten zones, where 1020 goats composed of three breeds
(Mubende, Kigezi, and Small East African) were sampled and measured for body weight, lin-
ear body size, and age. We confirmed that Mubende and Kigezi goats from the original
homeland had a higher mean body weight than reported in FAO reports. In addition,
Mubende appeared to perform better in pastoral rangelands, with a higher mean body
weight (38.1 kg) and body size being significantly higher (P < 0.0001) compared to other
zones. The mean body weight for the Kigezi breed in the original homeland (34 kg) was com-
parable to those from Western Savannah grasslands and pastoral rangelands and less than
that initially reported by FAO (30 kg). Similarly, there was no significant difference in the lin-
ear body size characteristics of Kigezi goats in the home zone of highland ranges relative to
those found in other agroecological zones (P > 0.05). Although the Small East African goats
were originally found in Northwestern Savannah grassland and Northeastern dryland zones,
they performed poorly regarding mean body weight and body size characteristics in the for-
mer zone. In the Northwestern Savannah grasslands, the mean body weight (23.8 kg) was
even less than that reported by FAO, which ranged between 25 and 30 kg. Finally, we con-
firmed that Mubende and Kigezi goats are significantly heavier than small East African goats
(p � 0.0001). The results of this study can be useful in designing precise management strat-
egies to improve indigenous goat productivity in different environments in Uganda