Natural & Applied Sciences

Research Papers/Topics Natural & Applied Sciences

Production of Organic Compost from Water Hyacinth (Eichhornia crassipes [Mart.] Solms) in the Lake Victoria Basin: A Lake Victoria Research Initiative (VicRes

Abstract The Lake Victoria Basin (LVB) supports one of the poorest and most populous rural populations in the East Africa region. The dipping fsh population has forced the community around the Lake Victoria to turn to farming for food crops to meet its daily food demands. Chemical fertilizer which is readily available has been the alternative source of improving soil condition which has led to eutrophication of the lake waters causing the temperature to rise in the process affecting most fre...

Green Remediation of Carbamazepine from Water Using Novel Magnetic Iron Modified Carbonized Baggasse: Kinetics, Equilibrium and Mechanistic Studies

Abstract Baggasse derived biochar magnetically modified with iron (α-Fe2O3-CBG) was fabricated, characterized and applied as a low-cost adsorbent for the removal of carbamazepine (CBZ), a pharmaceutically active compound which has been reported as an emergent water contaminant. Characterization of the synthesized (α-Fe2O3-CBG) composite showed that iron was effectively impregnated onto the carbonized bagasse network. The composite was able to achieve 60.9 % CBZ removal within a period of 4...

Probing the equatorial ionosphere using spread-F signatures and GPS scintillations at Maseno in East Africa

Abstract The Maseno (0.0°S, 34.6°E) ionosonde and the Mbarara (0.6°S, 30.7°E) GPS SCINDA receiver have been used to probe the equatorial ionosphere of the East Africa region using data obtained in 2012 and 2015. The equatorial spread-F (ESF) which appears as a spread on the F-layer on ionograms has been classified and their occurrence were found to have correspondence with GPS nighttime scintillations. The spread-F at equatorial and low-latitudes normally occurs during nighttime hours. T...

Meyer-Neldel rule for Cu (I) diffusion in In2S3 layers

Abstract The nature of barriers for atomic transport in In2S3 layers has been varied by addition of chlorine. Diffusion of Cu(I) from a removable CuSCN source was used to probe the variation of the barriers. The Meyer-Neldel (compensation) rule was observed with a Meyer-Neldel energy (EMN) and a proportionality prefactor (D00) amounting to 40 meV and 5 × 10−14 cm2/s, respectively. D00 shows that the elementary excitation step is independent of the specific mechanism and nature of th...

Role of Cl on Diffusion of Cu in In2S3 Layers Prepared by Ion Layer Gas Reaction Method

Abstract Ion layer gas reaction (ILGAR) method allows for deposition of Cl-containing and Cl-free In2S3 layers from InCl3 and In(OCCH3CHOCCH3)3 precursor salts, respectively. A comparative study was performed to investigate the role of Cl on the diffusion of Cu from CuSCN source layer into ILGAR deposited In2S3 layers. The Cl concentration was varied between 7 and 14 at.% by varying deposition parameters. The activation energies and exponential pre-factors for Cu diffusion in Cl-containing s...

In Silico Models for Anti-COVID-19 Drug Discovery: A Systematic Review

Abstract The coronavirus disease 2019 (COVID-19) is a severe worldwide pandemic. Due to the emergence of various SARS-CoV-2 variants and the presence of only one Food and Drug Administration (FDA) approved anti-COVID-19 drug (remdesivir), the disease remains a mindboggling global public health problem. Developing anti-COVID-19 drug candidates that are effective against SARS-CoV-2 and its various variants is a pressing need that should be satisfied. This systematic review assesses the existin...

Molecular Characterization of Indigenous Rhizobia from Kenyan Soils Nodulating with Common Beans

Abstract : Kenya is the seventh most prominent producer of common beans globally and the second leading producer in East Africa. However, the annual national productivity is low due to insufficient quantities of vital nutrients and nitrogen in the soils. Rhizobia are symbiotic bacteria that fix nitrogen through their interaction with leguminous plants. Nevertheless, inoculating beans with commercial rhizobia inoculants results in sparse nodulation and low nitrogen supply to the host plants b...

Acceptability and Nutritional Quality of Finger Millet (Eleusine coracana) Cookies Enriched with Cricket (Acheta domesticus)

Abstract The triple burden of malnutrition, characterized by being overweight, hidden hunger, and underweight, is prevalent in Sub-Saharan Africa, including Kenya. Edible crickets are recognized as a sustainable and affordable source of food rich in proteins, lipids, vitamins, and minerals. On the other hand, finger millet is also rich in proteins, nutrients, and antioxidants. This study evaluated the nutritional value of finger millet cookies enriched with crickets alongside the control (fi...

Molecular Characterization and Mineralizing Potential of Phosphorus Solubilizing Bacteria Colonizing Common Bean (Phaseolus vulgaris L.) Rhizosphere in Western Kenya

Abstract Phosphorus solubilizing bacteria (PSB) are a category of microbes that transform insoluble phosphates in soil into soluble forms that crops can utilize. Phosphorus in natural soils is abundant but poorly soluble. Hence, introducing PSB is a safer way of improving its solubility. The aim of this study was to genetically characterize and determine the mineralization capability of selected PSB colonizing rhizospheres of common beans in Western Kenya. Seven potential phosphorus solubili...

Estimation of Spatially Varying Parameters with Application to Hyperbolic SPDES

Abstract Parameter estimation is a growing area of interest in statistical signal processing. Some parameters in real-life applications vary in space as opposed to those that are static. Most common methods in estimating parameters involve solving an optimization problem where the cost function is assembled variously, for example, maximum likelihood and maximum a posteriori methods. However, these methods do not have exact solutions to most real-life problems. It is for this reason that Mont...

Abundance and Symbiotic Rhizobia Colonizing Soybean (Glycine max) in Soils of Kakamega County, Western Kenya

Abstract Identification of effective indigenous rhizobia strain nodulating soybean (Glycine max) was conducted in Kakamega County, Western Kenya. This study was carried out to establish the abundance and symbiotic efficiency of native rhizobia strains in soil samples collected from 12 sites in four agroecological zones within the region. The MPN enumeration technique was used to estimate the indigenous rhizobia numbers and showed that 54% of the sampled sites had high abundance. Rhizobia num...

Travelling Wave Analysis of a Diffusive COVID-19 Model

Abstract In this paper, a mathematical model based on a system of nonlinear parabolic partial differential equations is developed to investigate the effect of human mobility on the dynamics of coronavirus 2019 (COVID-19) disease. Positivity and boundedness of the model solutions are shown. The existence of the disease-free, the endemic equilibria, and the travelling wave solutions of the model are shown. From the numerical analysis, it is shown that human mobility plays a crucial role in the...

The status and challenges of a modern irrigation system in Kenya: A systematic review

Abstract The modernization efforts of the irrigation subsector in Kenya have been hampered by several challenges. This review describes the status and challenges facing irrigated agriculture in Kenya. The results indicated that as of 2018, the developed irrigation schemes covered an area of 222,240 ha, which is 16% of the irrigation potential of 1.34 million ha. Most large-scale irrigation schemes use the furrow system. Private and commercial farms and smallholder irrigation schemes use mo...

Sensitivity and Optimal Control Analysis of an Extended SEIR COVID-19 Mathematical Model

Abstract In this paper, a mathematical model based on a system of ordinary differential equations is developed with vaccination as an intervention for the transmission dynamics of coronavirus 2019 (COVID-19). The model solutions are shown to be well posed. The vaccine reproduction number is computed by using the next-generation matrix approach. The sensitivity analysis carried out on this model showed that the vaccination rate and vaccine efficacy are among the most sensitive parameters of t...

Effects of Sand-Harvesting on River Water Quality and Riparian Soil Physico-Chemical Properties

Abstract The widespread distribution of river sand-harvesting activities continues to degrade river water quality and the surrounding riverine environments. This study determined practical effects of sand-harvesting on two rivers in Kakamega County Kenya. Water samples were tested for turbidity and total suspended solids (TSS). For riparian soils, nitrogen (N), phosphorus (P), pH, organic carbon (OC), moisture content and textural class were determined on composite samples obtained from the ...


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