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Cockle (Anadara granosa) shells-based hydroxyapatite and its potential for defluoridation of drinking water
Get PDFThis research article was published by Elsevier, 2022The present study describes the synthesis and characterization of a hydroxyapatite (HAp)-based adsorbent derived from biogenic cockle (Anadara granosa) shells for the defluoridation of drinking water. The raw cockle shells and synthesized HAp were characterized by X-ray fluorescence spectroscopy (XRF), attenuated total reflection-Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopes-energy dispersive X-ray (FESEM-EDX) and Brunauer-Emmett-Teller (BET) surface area analysis. As demonstrated by FTIR, cockle shells were found to be composed of calcium carbonate (97.4%), an aragonite polymorphous type of carbonate mineral. XRD and SEM analysis supported the formation of a nanocrystalline HAp with an average crystal size of 19.08 nm and 57.1 nm, respectively, with a surface area of 105.8 m2/g and a pore size of 5.6 nm, as depicted by BET. Batch adsorption experiments were conducted using the Box-Behnken design (BBD) with five input parameters: adsorbent dose (2–10 g/L), initial fluoride concentration (10–80 mg/L), contact time (0.5–24 h), reaction temperature (303–333 K), and pH. (3–11). BBD revealed the following optimum conditions: adsorbent dose (6 g/L), initial fluoride concentration (45 mg/L), contact period 12.25 h, reaction temperature (303 K), and pH 3. Experimentally, the adsorption of fluoride on HAp fitted well with the non-linear Langmuir isotherm and linear pseudo-second order kinetics, signifying the chemisorption process. A maximum adsorption capacity (qm) of 15.374 mg/g, which is closer to the experimental value of 14.053 mg/g, was presented by the Langmuir isotherm. Thermodynamically, the adsorption process was spontaneous, endothermic, and stable in nature. The defluoridation mechanism was through electrostatic attraction, ion exchange, hydrogen bonding, and precipitation. Furthermore, the synthesized HAp and bone char were used to examine their efficacy in defluoridating field water: HAp performed better at natural pH, where the treated water met WHO and TBS standards, whereas bone char had insufficient fluoride removal, especially at high fluoride levels. As a result, this study suggests that HAp derived from Anadara granosa shells could be a viable adsorbent for the defluoridation of drinking water
We are what we eat, plus some per mill: Using stable isotopes to estimate diet composition in Gyps vultures over space and time
Get PDFThis research article published by John Wiley & Sons, Ltd, 20221. Dietary studies in birds of prey involve direct observation and examination of
food remains at resting and nesting sites. Although these methods accurately
identify diet in raptors, they are time-consuming, resource-intensive, and associated with biases from the feeding ecology of raptors like Gyps vultures. Our
study set out to estimate diet composition in Gyps vultures informed by stable isotopes that provide a good representation of assimilated diet from local
systems.
2. We hypothesized that differences in Gyps vulture diet composition is a function
of sampling location and that these vultures move between Serengeti National
Park and Selous Game Reserve to forage. We also theorized that grazing ungulates are the principal items in Gyps vulture diet.
3. Through combined linear and Bayesian modeling, diet derived from δ13C in Gyps
vultures consisted of grazing herbivores across sites, with those in Serengeti
National Park consuming higher proportions of grazing herbivores (>87%). δ13C
differences in vulture feather subsets did not indicate shifts in vulture diet and
combined with blood δ13C, vultures fed largely on grazers for ~159 days before
they were sampled. Similarly, δ15N values indicated Gyps vultures fed largely on
herbivores. δ34S ratios separated where vultures fed when the two sites were
compared. δ34S variation in vultures across sites resulted from baseline differences in plant δ34S values, though it is not possible to match δ34S to specific
locations.
4. Our findings highlight the relevance of repeated sampling that considers tissues
with varying isotopic turnover and emerging Bayesian techniques for dietary
studies using stable isotopes. Findings also suggested limited vulture movement between the two local systems. However, more sampling coupled with environmental data is required to fully comprehend this observation and its implication to Gyps vulture ecology and conservation
Assessment of Groundwater Quality under Changing Climate in Ngorongoro Conservation Area, Tanzania
Get PDFThis research article was American Society of Civil Engineers in 2022Understanding the hydrochemical composition of water resources in the Ngorongoro Conservation Area (NCA, Dodoma, Tanzania) related to climate variability is essential for sustainable development. Thus, the current study used the HYDRUS-1D model to assess the groundwater quality change due to the leaching of hydrochemicals from surface water under the climate variability of the NCA. This study observed that the area’s surface water had varying hydrochemical contaminants, whereas the groundwater is currently most suitable for drinking and domestic purposes. However, it is predicted that two anions (Cl−1 and PO4−3) and two cations (Na+ and K+) are expected to exceed the permissible limits from 2036 to 2050, considering the anticipated climatic conditions. Changes in groundwater quality for cations and anions are significantly correlated to evapotranspiration and temperature, with Pearson’s coefficient of determinations r
between 0.35 and 0.66. The findings of this study are necessary to benchmark better water resources management planning
Towards sustainability: Threat of water quality degradation and eutrophication in Usangu agro-ecosystem Tanzania
Get PDFThis research article was published by Elsevier in 2022The agrochemicals and nutrient losses from farming areas such as paddy farming significantly dictate quality and eutrophication of the freshwater resource. However, how farming and land use pattern affect water qualities and eutrophication remain poorly understood in most African agro-ecosystems. The present study characterized how paddy farming influences water qualities and eutrophication in 10 irrigation schemes in Usangu agro-ecosystem (UA). About 42 water samples were sampled from intakes, channels, paddy fields, and drainages and analyzed for EC, Cl, P, NH4-N, NO3-N, TN, Zn, Cu, Ca, and Mg. We observed water pH ranging from 4.89 to 6.76, which was generally below the acceptable range (6.5–8.4) for irrigation water. NH4-N concentration was in a range of 10.6–70.0 mg/L, NO3-N (8.4–33.9 mg/L), and TN (19.1–21,104 mg/L). NH4-N increased along sampling transect (sampling points) from intakes (5.7–29.1 mg/L), channels (19–20 mg/L), fields (12.9–35.8 mg/L), and outflow (10.6–70.0 mg/L), the same trend were found for NO3-N and TN. The TP determined in water samples were in the range of 0.01 to 1.65 mg/L; where some sites had P > 0.1 mg/L exceeding the allowable P concentration in freshwater resource, thus indicating P enrichment and eutrophication status. The P concentration was observed to increase from intake through paddy fields to drainages, where high P was determined in drainages (0.02–1.65 mg/L) and fields (0.0–0.54 mg/L) compared to channels (0.01–0.13 mg/L) and intakes (0.01–0.04 mg/L). Furthermore, we determined appreciable amount of potentially toxic elements (PTEs) such as Cu, Pb, Cd and Cr in studied water samples. The high N, P, and PTEs in drainages indicate enrichment from agricultural fields leading to water quality degradation and contaminations (eutrophication). The study demonstrates that water quality in UA is degrading potentially due to paddy rice farming and other associated activities in the landscape. Thus, the current study recommends starting initiatives to monitor irrigation water quality in UA for better crop productivity, and improved quality of drainage re-entering downstream through the introduction of mandatory riparian buffer, revising irrigation practices, to include good agronomic practices (GAP) to ensure water quality and sustainability
Field Margin Plants Support Natural Enemies in Sub-Saharan Africa Smallholder Common Bean Farming Systems
Get PDFThis research article was published by MDPI in 2022Flower-rich field margins provide habitats and food resources for natural enemies of pests
(NEs), but their potential, particularly in the tropics and on smallholder farms, is poorly understood.
We surveyed field margins for plant-NE interactions in bean fields. NEs most often interacted with
Bidens pilosa (15.4% of all interactions) and Euphorbia heterophylla (11.3% of all interactions). In cage
trials with an aphid-infested bean plant and a single flowering margin plant, the survival of Aphidius
colemani, the most abundant parasitoid NE in bean fields, was greater in the presence of Euphorbia
heterophylla than Bidens pilosa, Tagetes minuta, and Hyptis suaveolens. UV-fluorescent dye was applied
to flowers of specific field margin plant species and NE sampled from within the bean crop and field
margins using sweep-netting and pan-traps respectively. Captured insects were examined for the
presence of the dye, indicative of a prior visit to the margin. Lady beetles and assassin bugs were
most abundant in plots with B. pilosa margins; hoverflies with T. minuta and Parthenium hysterophorus
margins; and lacewings with T. minuta and B. pilosa margins. Overall, NE benefitted from field margin
plants, and those possessing extra floral nectaries had an added advantage. Field margin plants need
careful selection to ensure benefits to different NE groups
Analysis of land use and land-cover pattern to monitor dynamics of Ngorongoro world heritage site (Tanzania) using hybrid cellular automata-Markov model
Get PDFThis research articles was published in Journals Current Research in Environmental Sustainability Volume 4,2022Assessment of land-use and land-cover (LULC) change of any region is one of the prominent features used in
environmental resource management and its overall sustainable development. This study analyzed the LULC
changes of Ngorongoro Conservation Area (NCA) and its surroundings using Remote Sensing and Geographical
Information System integrated with Cellular Automata-Markov model. The LULC maps for the years 1995, 2005,
and 2016 were classified using unsupervised and supervised classification procedure, and projected for 2025 and
2035 under business-as-usual scenario using the CA–Markov model. The results indicated maximum gains and
losses in cultivated land and woodland in the study duration, respectively. The projected LULC for the period
2025 to 2035 showed a reduction in bushland, forest, water, and woodland, but an intensification in cultivated
land, grassland, bare land, and the built-up area. The natural forests with high environmental values were found
to be continuously declining under the current land management trend, causing the loss in the NCA’s ecological
values. For sustainable management, the authorities must reach conciliation between the existing LULC patterns
change and ecosystem services monitoring. A rational land use plan must be made to control the increase of
cultivated land and built-up area counting a rational land use plan and ecosystem services protection guidelines.
Decision makers should involve stakeholder to support improved land use management practices for balanced
and sustainable ecosystem services strategies
Heuristic Evaluation and Usability Testing of G-MoMo Applications
Get PDFThis Research Article was published by IADITIFinancial technology (FinTech) has swiftly revolutionized mobile money as one of the ways of accessing financial
services in developing countries. Numerous mobile money applications were developed to access mobile money
services but are hindered by severe authentication security challenges, thus, forcing the researchers to design a secure
multi-factor authentication (MFA) algorithm for mobile money applications. Three prototypes of native mobile money
applications (G-MoMo applications) were developed to confirm that the algorithm provides high security and is
feasible. This study, therefore, aimed to evaluate the usability of the G-MoMo applications using heuristic evaluation
and usability testing to identify potential usability issues and provide recommendations for improvement. Heuristic
evaluation and usability testing methods were used to evaluate the G-MoMo applications. The heuristic evaluation
was carried out by five experts that used the 10 principles proposed by Jakob Nielsen with a five-point severity rating
scale to identify the usability problems. While the usability testing was conducted with forty participants selected
using a purposive sampling method to validate the usability of the G-MoMo applications by performing tasks and
filling out the post-test questionnaire. Data collected were analyzed in RStudio software. Sixty-three usability issues
were identified during heuristic evaluation, where 33 were minor and 30 were major. The most violated heuristic
items were “help and documentation”, and “user control and freedom”, while the least violated heuristic items were
“aesthetic and minimalist design” and “visibility of system status”. The usability testing findings revealed that the G-
MoMo applications’ performance proved good in learnability, effectiveness, efficiency, memorability, and errors. It
also provided user satisfaction, ease of use, aesthetics, usefulness, integration, and understandability. Therefore, it
was highly recommended that the developers of G-MoMo applications fix the identified usability problems to make
the applications more reliable and increase overall user satisfaction
Fluoride Sorption Using Zirconium ion-impregnated Macadamia Nutshell-Derived Biochar from Aqueous Solution: Adsorption Isotherms and Kinetic Modeling
Get PDFThis research articles was published by Research Article in 2022Zirconium ion-impregnated macadamia nutshell biochar (ZMNB) was synthesized and tested for its fluoride sorption capacity by exploiting batch experiments. Four temperatures (300, 400, 500, and 600 ℃) were used to pyrolyze the macadamia nutshells to yield macadamia nutshell biochar (MNB) which was separately impregnated with Zr (IV) aqueous solution. Both non-modified and chemically modified MNB were assessed by X-ray diffraction (XRD), attenuated total reflection Fourier Transform Infra-red (ATR-FTIR), field emission scanning electron microscope-energy dispersive X-ray (FESEM-EDS), thermogravimetric analysis, and Brunauer-Emmett-Teller (BET) surface area analyzer. The sequence of F− adsorption capacities for the synthesized biosorbents was ZMNB 300 > ZMNB 400 > ZMNB 500 > ZMNB 600, which revealed the influence of pyrolysis temperature on sorption process. ZMNB 300 had a maximum percentage fluoride removal effectiveness of 99.05% using 1.0 g L− 1 adsorbent lot, at neutral pH for an interaction period of 1 h. The adsorption studies suited perfectly with the pseudo-second-order kinetic model and the linear Langmuir isotherm, affirming a chemisorption process. Thermodynamic studies revealed that the calculated ΔG° value (-5.593 kJ mol− 1) ascribed the rapidity and spontaneity of the sorption action, ΔH° value (30.102 kJ mol− 1) elucidated the endothermic, irreversible and chemisorption process whereas the ΔS° value (118.55 J mol− 1 K− 1) signified the F− adsorption’s random trait on the solid or liquid interface of the ZMNB 300. Results from the sorption experiments using fluoride-contaminated natural water removed the F− ions below the curbed WHO standard (1.5 mg L− 1) for drinking water and therefore, a potential material for practical applications
Contribution of the Dolichos Lablab value chain to farmer's household livelihood assets in Tanzania
Get PDFThis research article was published in the Journal of Heliyon Volume 8, Issue 11, November 2022Lablab is a legume with multiple uses as food, feed, and organic fertilizer. However, it is underutilized, and its empirical contribution to farmers' livelihoods is limited. This study examined the Lablab value chain (LVC) relative to smallholder farmers' livelihood assets in Tanzania. Data on Lablab farming, its value chain, and its contribution to the farmers’ livelihood assets were collected from four districts of Tanzania known for Lablab production. The results showed that the LVC mapping comprised systems, actors, and interdependent activities, the key systems being input supply, tillage, intercropping, and marketing. Seed supply was through the recycling of the last harvest (48.8%), while intercropping (56.5%) and hand-hoeing (51.6%) were the primary cultivation systems, with farm gates and/or local markets serving as the marketing locations. The grown seeds were mainly black (62.3%) due to external marketability but were rarely eaten. Although farmers were the major chain actors, traders were highly active in the marketing segment, leaving farmers out of the bargain art protocol. Generally, Lablab production generated almost 90% of the farmers' revenue by multiple linear regression. Based on farmers' five asset categories, natural and human assets contributed 70% and 50% respectively, while there was less contribution from social, financial, and physical assets. The study recommends networking exposure to reliable marketplaces with good prices, improved seed availability, and financial services for Lablab farmers in Tanzania. To sustain the smallholder farmers' five livelihood assets from Lablab, researchers and policymakers must pay attention to the three linkages of the LVC
Potential Opportunities and Challenges of Deploying Next Generation Sequencing and CRISPR-Cas Systems to Support Diagnostics and Surveillance Towards Malaria Control and Elimination in Africa
Get PDFA research article was submitted to Clinical Microbiology Volume 12 - 2022Recent developments in molecular biology and genomics have revolutionized biology and medicine mainly in the developed world. The application of next generation sequencing (NGS) and CRISPR-Cas tools is now poised to support endemic countries in the detection, monitoring and control of endemic diseases and future epidemics, as well as with emerging and re-emerging pathogens. Most low and middle income countries (LMICs) with the highest burden of infectious diseases still largely lack the capacity to generate and perform bioinformatic analysis of genomic data. These countries have also not deployed tools based on CRISPR-Cas technologies. For LMICs including Tanzania, it is critical to focus not only on the process of generation and analysis of data generated using such tools, but also on the utilization of the findings for policy and decision making. Here we discuss the promise and challenges of NGS and CRISPR-Cas in the context of malaria as Africa moves towards malaria elimination. These innovative tools are urgently needed to strengthen the current diagnostic and surveillance systems. We discuss ongoing efforts to deploy these tools for malaria detection and molecular surveillance highlighting potential opportunities presented by these innovative technologies as well as challenges in adopting them. Their deployment will also offer an opportunity to broadly build in-country capacity in pathogen genomics and bioinformatics, and to effectively engage with multiple stakeholders as well as policy makers, overcoming current workforce and infrastructure challenges. Overall, these ongoing initiatives will build the malaria molecular surveillance capacity of African researchers and their institutions, and allow them to generate genomics data and perform bioinformatics analysis in-country in order to provide critical information that will be used for real-time policy and decision-making to support malaria elimination on the continent