Natural & Applied Sciences

Research Papers/Topics Natural & Applied Sciences

The Contribution of Subtidal Seagrass Meadows to the Total Carbon Stocks of Gazi Bay, Kenya

Abstract Seagrass beds occur globally in both intertidal and subtidal zones within shallow marine environments, such as bays and estuaries. These important ecosystems support fisheries production, attenuate strong wave energies, support human livelihoods and sequester large amounts of CO2 that may help mitigate the effects of climate change. At present, there is increased global interest in understanding how these ecosystems could help alleviate the challenges likely to face humanity and the...

Vertical Distribution of Plant-Parasitic Nematodes in Sweet Potato

Abstract Plant-parasitic nematodes (PPN) are harmful pests that have become a severe threat to crop production worldwide. Diversity of PPN at horizontal and spatial scales influence the effectiveness of control strategies. This study evaluated the vertical distribution of PPN genera at 0 cm to 30 cm and 30 cm to 60 cm in sweet potato fields in Central, Manyatta, and Nembure regions of Embu County, Kenya. A significant region × depth interaction was observed for Tylenchus. For all the other ...

Nematode assemblages, food web indices and metabolic footprints in maize-pigeon pea agro-ecosystems

Abstract Pigeon pea (Cajanus cajan L.) and maize (Zea mays L.) are important food crops in developing countries due to their multiple benefits. However, their production is constrained by plant-parasitic nematodes (PPN) which cause significant yield losses. Understanding the nematode-based soil food web structure in maize-pigeon pea agroecosystems will allow sustainable PPN management by improving soil health. This study explored nematode community assemblages, indices and metabolic footprin...

Genetic Diversity of African Nightshade (Solanum nigrum L.) Complex Accessions from Western Kenya

Abstract Kenya. Despite its importance as a nutritious vegetable and having inherent medicinal value, African nightshade has been neglected, few farmers are growing it, there is potential reduction of food supply and these may be as a result of few studies carried out to improve the crop. Recently, growing demand is necessary for the development of improved, high yielding varieties, intensify diversity studies of interest, conservation and utilization of genetic resources especially in Weste...

Formulating Black Scholes Equation Using a Jump Diffusion Heston’s Model

Abstract/Overview In modern financial mathematics, accurate values are obtained by taking into account a considerable number of more realistic assumptions in logistic Black Scholes equation. The aspects considered here are cost of transactions in trading, perfect illiquid markets and risks that occur from non – protected portfolio or large investments that have a lot of impact on price of the assets, volatility, the percentage drift and the life of the portfolio itself. In modern world ...

Derivation of Black Scholes Equation Using Heston’s Model with Dividend Yielding Asset

Abstract/Overview Black Scholes formula is crucial in modern applied finance. Since the introduction of Black – Scholes concept model that assumes volatility is constant; several studies have proposed models that address the shortcomings of Black – Scholes model. Heston’s models stands out amongst most volatility models because the process of volatility is positive and is a process that obeys mean reversion and this is what is observed in the real market world. One of the shortcomin...

Simulation of the charge ratio of cosmic ray muons in extensive air showers using corsika

Abstract/Overview The interaction of primary cosmic rays in the atmosphere produces, among other particles, pions and kaons. They decay to muons, which form an important component of extensive air showers, which can be measured on the Earth's surface. The ratio of positively to negatively charged muons, called the muon charge ratio, provides important information about the cosmic ray interactions in the atmosphere. In this study, the theoretical hadronic interaction models in the cosmic r...

Characterization of Topological Points in Big Data Sets of Hausdorff Spaces

Abstract/Overview Topological Data Analysis (TDA) is an important aspect in the field of topological data theory since the 21st century’s first decade. Modern TDA utilizes the structural characteristics of Big Data (BD), otherwise known as point cloud data sets. Topology and Geometry are tools used to analyze highly complex and multi-dimensional data by creating a summary of these characteristics to uncover hidden features in these datasets, while preserving feature relationships with...

Characterization of Fungal Leaf Spot Disease and Varietal Susceptibility in Sweet Potato (Ipomoea Batatas L.) Grown in Parts of Western Kenya

Abstract/Overview Increased human population has led to increased vulnerabilities to hunger and reduced sources of affordable food. Sweet potato (Ipomoea batatas L.) is a root vegetable with large, starchy, tuberous roots, consumed worldwide. It is a potential food security crop, with high nutritional and economic value. Production of sweet potatoes in Kenya is low due to disease constraints such as sweet potato leaf spot (SPLS). Fungal SPLS results in reduced tuber yield, since the patho...

Abundance and control of malaria mosquito larvae in the traditional water management agro-ecosystem of Kasagam, western Kenya /

Abstract/Overview This study investigated the abundance and control of malaria mosquito larvae in a traditional water management agro-ecosystem of Kasagam, Kisumu City, western Kenya. The study of larval habitats of malaria vectors is important in determining abundance and fitness of resultant adult mosquito populations and planning for suitable control measures. Dominant types of plants found in the study site were identified, recorded and categorized. Sampling of mosquito larvae was don...

Numerical Analysis of Holling Type Ii Functional Response Predator-Prey Model with Time Delay Optimal Selective Harvesting

Abstract/Overview Population dynamics indicate the changes in size and composition of population through time, as well as biotic and abiotic factors influencing those changes. Predator-prey (PP) relationship with harvesting and functional response involving prey refuge with Holling type I functional response (HTIFR) has been studied with recommendations on their extension to include Holling type II functional response (HTIIFR). There persists a problem in fifinding the numerical solution ...

Numerical Analysis of Third Order Advection-Viscous Wave Equation Using Finite Difference Method

Abstract/Overview Wave equation is a linear hyperbolic partial differential equation (PDE) which describes the propagation of a variety of waves arising in physical situations. In its simplest form, the one dimension wave equation refers to a scalar function u = u(x, t), which satisfy the PDE utt = C2uxx. When the wave propagates in complex media, form of the governing wave equation changes, so in particular a viscous loss in term µuxxt and the advection term αux are added to the right ...

On norm preserving conditions for local automorphisms of commutative banach algebras

Abstract/Overview Many studies on preserver problems have been focusing on linear preserver problems in matrix theory. Kadison and Sourour showed that the local derivations of Von Neumann algebras are continous linear maps which coincide with some derivation at each point in the algebra over the field of complex numbers. Most of the studies have been focusing on the spectral norm preserver and rank preserver problems of linear maps on matrix algebras but not on norm preserver problems for...

Density and Dentability in Norm-Attainable Classes

Abstract/Overview We establish the norm-denseness of the norm-attainable class $NAB(H)$ in the Banach algebra $B(H)$, which consists of all bounded linear operators on a complex Hilbert space $H$. Specifically, for every $O in NAB(H)$ and each $epsilon>0$, there exists $O' in B(H)$ such that $|O - O'| < epsilon$. We achieve this characterization by utilizing the convergence of sequences and the existence of limit points. The properties $A$ and $B$ of Lindenstrauss are sufficient to ensure...

Numerical Analysis of Prey Refuge Effects on the Stability of Holling Type III Four-Species Predator Prey System

Abstract/Overview The dynamic behavior of a multi-species system that includes a prey refuge and a Holling type III functional response is examined in this work. The pre-requisites for the presence of the equilibrium points, as well as their local and global stabilities, for the suggested system are analyzed and derived. The Routh-Hurwitz criterion and the eigenvalue technique are used to study the local stabilities. On the other hand, the global stabilities have been studied using the Ly...


226 - 240 Of 8880 Results
@