Abstract Mining is an economic activity that has been practiced for time immemorial. Land degradation from old mines operations is known in almost all the countries but they have been few systematic surveys to quantify the nature of associated problems so as to prioritize remediation action. There is knowledge in the techniques of rehabilitating both operational and abandoned sites yet there is still delay in remediation action. The enforcement of the Environmental Management and Co-ordinati...
Abstract his work studies variations of ionospheric total electron content (TEC) during four distinct solar eclipse events over the Ethiopia region. Dual-frequency global positioning system (GPS) data obtained from UNAVCO over Addis Ababa (9.036°N, 38.76°E) and Bahir Dar (11.6°N, 37.34°E) stations are used to examine the ionospheric variability during two annular solar eclipses on 15 January 2010 and 1 September 2016, a partial solar eclipse on 4 January 2011, and a hybrid solar eclipse ...
Abstract/Overview Carbon nanomaterials have recently attracted wide scientific applications due to their tunable properties. These novel materials act as best fillers that can provide substantial benefits due to their high strength, thermal conductivity, and electrical conductivities. With their huge applications as bulk materials, when implemented in polymer matrix as fillers, they give rise to new promising materials with which their properties can be tuned to suit a particular applicat...
Abstract/Overview A magnetically active nanocomposite material has been synthesized from the reaction mixture of magnetite core iron nano-particles electrostatically coated with SiO2, hydrotalcite nanosheets ([Eu8 (OH) 20 (H2O)n] 4+), and decatungstophosphate anion ([α-PW10O367−]). The resulting nanocomposite material, denoted as Fe34@SiO2@LEuH@PW10, is demonstrated to effectively adsorb chromate anions from aqueous solutions, the adsorption isotherms fit the Langmuir model with a capa...
Abstract/Overview Unilameller nanosheets with a lateral dimension of one nanometer have been isolated from a colloidal solution of europium-containing layered rare-earth hydroxide (LRH) material by the flocculation method. The nanosheets were achieved by changing pH of the colloidal solution from 6.7 to 11.5. The resultant flocculated nanosheets show high efficiency in sorption of fluoride anions from aqueous media (40 mmol/g), providing a potentially useful sorbent material for water p...
Abstract/Overview Aflatoxin B1 is a toxin produced as secondary fungal metabolites by the fungus Aspergillus, particularly A. flavus. The toxin has significantly contaminated the food supply chain especially cereals in Kenya. Kenya Bureau of Standards (KEBS) has recently banned five maize flour brands, citing high aflatoxin levels. They also suspended seven peanut butter products and the permits of their parent companies over aflatoxin contamination. The huge losses encountered by these c...
Abstract/Overview It has been suggested that Plasmodia manipulate their vertebrate hosts to enhance parasite transmission. Using a dual-choice olfactometer, we investigated the attraction of Anopheles gambiae to 50 Kenyan children (aged 5–12 years) who were naturally infected with Plasmodium falciparum or non-infected controls. Microscopic gametocyte carriers attracted almost 2 times more mosquitoes than children who were parasite free, harboured asexual stages, or had gametocytes at su...
Abstract/Overview The plant species Lonchocarpus eriocalyx Harms (Fabaceae) is a deciduous slender tree or shrub which grows up to 15 m tall. It is an important medicinal plant in Kenya used to treat a wide range of ailments including eye infection, wound and ulcer. However, little is known about its chemical constituents. The present study aims to isolate secondary metabolites from the plant leaves along with their various biological activities. Eight compounds, namely friedelin (1), lup...
Abstract/Overview Socio-economic and medical information on Bondo sub-county community was studied to help establish the relationship between the water quality challenges, community health and water rights conditions. Health challenges have been linked to water quality and household income. A total of 1,510 households/respondents were studied by means of a questionnaire. About 69% of the households have no access to treated water. Although 92% of the respondents appear to be aware that tr...
Abstract/Overview Sap flux density (SFD) measurements were used, in combination with morphological characteristics of trees and forest structure, to calculate whole-tree transpiration, stand transpiration (St) and mean canopy stomatal conductance (Gs). Analysis based on the relationships between the morphological characteristics of trees and whole tree water use, and on the responses of SFD and Gs to short wave radiation (RR), vapor pressure deficit (VPD) and soil water content (SWC) duri...
Abstract/Overview Forests are some of the key natural assets that provide a wide range of goods and services to forest adjacent communities. However, there is inadequate information on the factors that influence community members’ level of dependence on forest resources. This study examined and analyzed factors that influence dependence of households on non-timber forest products from South Nandi forest, Kenya. 431 household heads from 9 villages were interviewed using proportional rand...
Abstract/Overview Thiocarbohydrazide synthesis is an important intermediate step for many hydrazine organic synthetic reactions. Synthesis of thiocarbohydrazide can be done by reaction of carbon disulfide with hydrazine (hydrazinolysis) in water at 0°C giving 25% yield (based on [hydrazine]). However, in this article, we achieve a 96% yield (based on [hydrazine]) by carrying out the reaction in methanol at 24°C. The thiocarbohydrazide is then used to synthesize 1,5-bis (2-hydroxybenzald...
Abstract/Overview Herbal medicine has been used for many years and it remains widespread in developing countries while the use of complementary alternative medicine is increasing rapidly in developed countries. Senna didymobotrya is important for its medicinal use among many communities to treat a wide range of ailments. The study examines the patterns of morphological variation and phenetic relationships among 39 populations of S.didymobotrya in Kenya using17 quantitative and 17 qualitat...
Abstract/Overview The electrical and optical properties of cuprous oxide (Cu2O) thin films prepared by D.C. reactive magnetron sputtering technique have been systematically studied. The influence of the film deposition conditions on the opto-electrical properties has been investigated and has helped to solve the puzzles of difficulties associated with preparation of high quality Cu2O films. This is because there is usually co-deposition of phases of Cu, Cu2O and CuO during the preparation...
Abstract Africa is under pressure from climate stresses and is highly vulnerable to the impacts of climate change. In Kenya, agriculture is the backbone of the economy making it an important contributor to food security of rural households. Currently crop productivity is being affected by continued climate variations and decline in soil fertility. Adaptation to climate change requires to be given high and urgent priority for sustainable crop production. A study was conducted in Mavuria ward,...