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Investigation of bentonite as a partial replacement in the production of Portland pozzolana cement in concrete containing sisal and waste nylon fibers
(NM-AIST, 2025-07) Fode, Tsion
Concrete is the most widely used construction material globally, resulting in the extensive consumption of ordinary Portland cement (OPC) and frequent use of steel or virgin plastic fibers to enhance ductility. However, the production of OPC particularly clinker and steel or plastic fibers associated with significant environmental impacts, energy consumptive and high cost. Also, in some adverse environments OPC does not meet the strength and durability demands of modern construction. The present study addresses these challenges by utilizing bentonite to produce high strength and durable cement by optimizing the activation of bentonite that can substitute part of the clinker using response surface method- central composite design. Also, this study used waste mosquito net and treated sisal fibers through novel treatment of sisal fiber by calcined bentonite slurry that optimized sisal fiber breaking load, degradation resistance, and lower water absorption for its effective use in the cement composite materials. A comprehensive evaluation of mineralogical, microstructural, durability, physical, and mechanical properties was conducted on the optimized Portland Pozzolana Cement (OPPC) produced with activated bentonite and treated sisal fiber. Furthermore, concrete mixes incorporating OPPC and various dosages of waste mosquito net fiber, both with and without treated sisal fiber, were analyzed for their performance. The results demonstrated that the optimized activated bentonite successfully produced a Portland pozzolana cement type CEM II/B-P 42.5M that improved 28days compressive strength by 24.94% and reduced free lime content by 3.08% compared to the control OPC. OPPC also exhibited significantly enhanced durability under adverse conditions, including acidic, salt, and high-temperature environments. Besides these, bentonite treated sisal fiber increased the breaking load by 33.37%, enhanced degradation resistance by 98%, and reduced water absorption by 60.95%. It also reduced mass loss at elevated temperatures by 28.18% at 367°C and 29.08% at 600 °C compared to raw sisal fiber. Moreover, concrete incorporating OPPC and waste mosquito net fiber with treated sisal fiber demonstrated significant improvements in crack resistance, compressive and splitting tensile strength, durability against acidic attack, and performance at elevated temperatures up to 300 °C, compared to concrete made with OPPC and waste mosquito net fiber without treated sisal fiber.
Critical thermal thresholds for survival and feeding in the invasive bark beetle Pagiocerus frontalis reveal mechanisms of stored-maize vulnerability
(Springer Nature, 2026-05-19) Chidege, Maneno; Ndakidemi, Patrick; Venkataramana, Pavithravani
Stored grains are highly vulnerable to insect pests, which can cause significant post-harvest losses worldwide. The invasive bark beetle Pagiocerus frontalis (Coleoptera: Curculionidae: Scolytinae) poses a major threat to maize and avocado seeds, yet the influence of temperature on its biology and damage potential is poorly understood. Here, we examined the effects of six constant temperatures (13, 17, 21, 25, 29, 33 °C) on survival, development, reproduction, and grain damage. Beetles thrived under moderately warm conditions (21, 25 and 29 °C), with the highest progeny, grain damage, and weight loss at 25 °C, while extreme temperatures (13 or 33 °C) suppressed activity and reproduction. These findings clarify the species’ thermal preferences and suggest that controlling storage temperature, either by cooling or heat treatment, could reduce pest-induced losses, providing a sustainable, non-chemical strategy for protecting stored grains. This information can also be incorporated into climate-based predictive models to forecast pest survival, establishment, and potential damage.
Climate-related health threats in Tanzania: a multi-level analysis of key policies, strategies and community response
(Oxford University Press, 2026-05-14) Urassa, Aloyce; Finda, Marceline; Okumu, Fredros; Kreppel, Katharina
Tanzania faces increasing climate-sensitive health threats, including vector-borne diseases, water-borne infections, and malnutrition. Effective preparedness at both national and community levels is critical for health system resilience and livelihood security. This study applied a multilevel mixed-methods approach to assess Tanzania’s policy structures and community-level experiences related to climate-health preparedness. Between January 2024 and May 2025, we conducted a concurrent mixed-methods study. At national level, we reviewed climate-health policy documents, mapped 30 key stakeholders, and conducted 15 semi-structured interviews with representatives from government ministries, research institutes, development partners and non-government organizations. At community level, we surveyed 388 adults and conducted eight focus group discussions in four councils in southern Tanzania. Data were analyzed and triangulated across all sources. Tanzania has developed several climate-health policies and community initiatives. However, gaps remain in cross-sectoral coordination, financing, and policy implementation. National stakeholders cited challenges in translating strategies into community-level action. Among community respondents, 77% acknowledged climate change and 97% reported exposure to hazards such as floods, drought, or extreme heat. Health impacts included malaria surges, diarrhoeal disease, and food scarcity. While 73.7% had received some government assistance, access to reliable health and climate information was limited. Households relied mainly on personal observations and informal networks. Communities and institutions jointly emphasized four priorities: strengthened risk communication, climate-smart agriculture, resilient health facilities, and inclusive early-warning systems. Strengthening multilevel governance, financing mechanisms, and community-driven adaptation planning is essential to improve Tanzania’s preparedness for climate-related health threats.
An analysis of antibiotic use in livestock in three East African livestock production systems
(Research Square, 2026-05-07) Loosli, Kathrin; McIntyre, Heather; Matthews, Louise; Johnson, Paul; Almadhoon, Hossam; Bootthong, Kamolsri; Buyugu, Paul; Ibrahim, Yusuf; Lea, Rachel; Manangwa, Oliva; Nthambi, Mary; Melubo, Matayo; Mnzava, Kunda; Mramba, Furaha; Nasuwa, Fortunata; Shinini, Tilla; Shirima, Gabriel; Muwonge, Adrian; Torr, Steve; Mshana, Stephen; Mmbaga, Blandina; Davis, Alicia; Lembo, Tiziana; Auty, Harriet
Antibiotic use in livestock is prevalent in low-resource settings due to high infection rates and inadequate veterinary services. We investigated antibiotic use in livestock across three agricultural production systems in northern Tanzania. We employed a mixed-method approach, including three cross-sectional surveys (n = 161, 1226 and 82), interviews (n = 30) and observations (n = 43). Qualitative interviews were analysed using coding and association matrices, while descriptive analyses and generalised linear models identified factors associated with antibiotic use. Oxytetracycline was the most commonly used antibiotic across study communities. Pastoralists reported higher antibiotic usage, and a broader range of antibiotics used compared to agropastoralists and smallholders. Farmers primarily purchased antibiotics from stores and relied on advice from peers or sellers, often using prior experience to guide treatment. Antibiotics were frequently used for the treatment of generic clinical signs and of non-bacterial infections, or preventatively. We identified problematic practices such as incorrect administration routes, inobservance of withdrawal periods and the use of antibiotics for human use in livestock. Pastoralists were more likely to use antibiotics compared to other production systems (OR = 3.92 vs. agropastoralists; OR = 7.87 vs. smallholders). Cattle were the species for which antibiotics were used the most (OR = 6.32 vs. poultry; OR = 2.29 vs. sheep/goats). The reported number of treatments administered per cow per year was significantly higher in smaller herds and in households that purchased antibiotics from markets. Variations in antibiotic treatment practices were linked to differences in healthcare access, disease risks, cultural norms and proximity to urban centres. Tailored interventions are needed to address challenges unique to each production system. However, community-driven awareness campaigns, investment in veterinary services, biosecurity measures and vaccination programmes would improve understanding and reduce reliance on antibiotics across production systems in this and similar settings, and would have knock-on effects on antimicrobial resistance risks.
Food Safety and Microbial Risks in Small-Scale Anchovy (Stolephorus spp.) Processing
(Journal of Pure and Applied Microbiology, 2026-05-05) Omary, Bally; Nyangoko, Baraka,; Lyimo, Beatus; Matemu, Athanasia
Traditional food processing methods such as salting, drying, and boiling are essential for enhancing food security, yet improper application of these techniques may pose safety risks. This study assessed food safety practices in the traditional processing of anchovy (Stolephorus spp.) among small-scale processors in Bagamoyo District, Tanzania. Data were collected through household surveys (n = 305), direct observation, and laboratory analysis of 120 samples obtained from fresh, salt-boiled, and sun-dried anchovies. Results indicated that 62% of processors lacked awareness of proper handling practices, 81% had not received formal food safety training, and only 60% were familiar with regulatory authorities. About 30% of respondents reported that delays before processing contributed to the deterioration of anchovy quality. Microbial analysis across the processing stages detected Escherichia coli in 20% (mean: 1.43 × 10 CFU/g) of fresh, 55% (mean: 1.73 × 105 CFU/g) of salt-boiled, and 20% (mean: 3.75 × 104 CFU/g) of sun-dried samples, while Staphylococcus aureus was present in 68% (mean: 8.35 × 103 CFU/g) of fresh and all salt-boiled and sun-dried samples (mean: 7.93 × 103 CFU/g and 2.48 × 103 CFU/g respectively); Salmonella spp. were not detected (