Natural & Applied Sciences

Research Papers/Topics Natural & Applied Sciences

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 ...

Comparative effects of nitrogen, phosphorus and potassium on Radopholus similis infection in East African Highland Banana plants as influenced by rhizosphere biota

Abstract Root parasitism by Radopholus similis may vary under different nutritional conditions and soil substrates. Such variations in nematode infection may affect deductions from evaluations of pest control measures. Three parallel factorial experiments (nutrients × soil sterility × nematode) were conducted to investigate the effects of N-P-K and soil biota on R. similis infection and banana plant growth. Chlorophyll content was lower in plants receiving N-deficient solution or w...

Factors associated with uncorrected refractive errors in school-going adolescents in Kakamega County, Kenya

Abstract Background: Uncorrected refractive errors (URE) present an enormous burden on children in Kenya. The study investigated factors associated with URE in school-going adolescents in Kakamega County, Kenya. Material and methods: An observational, cross-sectional study with multistage sampling was conducted with randomly selected secondary school students in forms one to four. Comprehensive clinical examinations conducted by optometrists were used to determine participants’ URE types a...

Occurrence and Distribution of Per- and Polyfluoroalkyl Substances from Multi-Industry Sources to Water, Sediments and Plants along Nairobi River Basin, Kenya

Abstract Per- and polyfluoroalkyl substances (PFAS) are ever-present pollutants in the environment. They are persistent and bio-accumulative with deleterious health effects on biota. This study assesses the levels of PFAS in environmental matrices along the Nairobi River, Kenya. An aggregate of 30 PFAS were determined in water, while 28 PFAS were detected in sediments and plants using solid phase extraction then liquid chromatography–mass spectrometric techniques. In water, higher levels o...

Effects of oil exploration on surface water quality- a review

Abstract The oil industry is a source of revenue and foreign exchange for an economy. Nevertheless, oil exploration is an inherent risk to the environment due to the pollution of water resources, especially surface water resources. The main waste is produced water which is increasing around the world .As a consequence,water pollution resulting from normal oil drilling, refining, distribution, and accidents is the principal concern of oil exploration in the environment. Oil pollution is assoc...

Ethernal Conversion to Butanol over Small Coinage Metal Clusters: An Experimental and Computational Study

Abstract We illustrate the mechanism for the C–O, C–H and O–H bond activation in the coupling of ethanol to butanol over small coinage clusters (copper, silver and gold). It is found that charge transfer interactions between the clusters and the alcohol initiate their reactions allowing a chemisorption step. The binding energy is calculated, whereby ethanol adsorbs very strongly on Au in comparison to Ag and Cu. The nature of bonding is investigated using natural bond orbital (NBO) ana...

Red cell distribution width as a surrogate marker of haemoglobinopathies in western Kenya

Abstract distribution width (RDW) measures anisopoikiloytosis and is readily reported by haematology analysers as a complete blood count parameter. The utility of RDW as a diagnostic marker of haemoglobinopathies in Kenya remains undetermined and undocumented. Objective: This study aimed to determine the diagnostic efficacy of RDW in discriminating haemoglobinopathy and haemoglobinopathy-free cases in Kenya. Methods: The case-control study used randomly selected haematology analyser outputs ...


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