Chaotic Convection in a Viscoelastic Fluid Saturated Porous Medium with a Heat Source

Chaotic convection in a viscoelastic fluid saturated porous layer, heated from below, is studied by using Oldroyd’s type constituting relation and in the presence of an internal heat source. A modified Darcy law is used in the momentum equation, and a heat source term has been considered in energy equation. An autonomous system of fourth-order differential equations has been deduced by using a truncated Fourier series. Effect of internal heat generation on chaotic convection has been investigated. The asymptotic behavior can be stationary, periodic, or chaotic, depending upon the flow parameters. Construction of four-scroll, or “two-butterfly,” and chaotic attractor has been examined

Mathematical Modeling and Analysis of Leukemia: Effect of External Engineered T Cells Infusion

In this paper, a nonlinear model is proposed and analyzed to study the spread of Leukemia by considering the effect of genetically engineered patients T cells to attack cancer cells. The model is governed by four dependent variables namely; naive or susceptible blood cells, infected or dysfunctional blood cells, cancer cells and immune cells. The model is analyzed by using the stability theory of differential equations and numerical simulation. We have observed that the system is stable in the local and global sense if antigenicity rate or rate of stimulation of immune cells is greater than a threshold value dependent on the density of immune cells. Further, external infusion of T cells (immune cells) reduces the concentration of cancer cells and infected cells in the blood. It is observed that the infected cells decrease with the increase in antigenicity rate or stimulation rate of immune response due to abnormal cancer cells present in the blood. This indicates that immune cells kill cancer cells on being stimulated and as antigenicity rate increases rate of destruction of cancer cells also increase leading to decrease in the concentration of cancer cells in the body. This decrease in cancer cells further causes decrease in the concentration of infected or dysfunctional cells in the body

Modeling Spread of Polio with the Role of Vaccination

In this paper, we have proposed and analyzed a nonlinear mathematical model for the spread of Polio in a population with variable size structure including the role of vaccination. A threshold parameter, R , is found that completely determines the stability dynamics and outcome of the disease. It is found that if R 1, the disease free equilibrium is stable and the disease dies out. However, if R \u3e1, there exists a unique endemic equilibrium that is locally asymptotically stable. Conditions for the persistence of the disease are determined by means of Fonda’s theorem. Moreover, numerical simulation of the proposed model is also performed by using fourth order Runge - Kutta method. Numerically, it has been found that the system exhibits steady state bifurcation for some parameter values. It is concluded from our analysis that endemic level of infective population increases with the increase in rate of transmission of infection due to infective among susceptible class that further enhances because of transmission of infection due to latent hosts. A particular value of disease transmission coefficient r is found for which exposed and infective population dies out. It is found that periodic outbreak of the disease occurs when infection due to exposed and infective class occurs at the same rate. It is also observed from our analysis that although vaccination helps in eradicating polio by decreasing endemic equilibrium level yet careful administration of vaccination is desired because if vaccine is administered during incubation period, endemic equilibrium level increases and disease persists in the population

Qualitative Analysis of a Modified Leslie-Gower Predator-prey Model with Weak Allee Effect II

The article aims to study a modified Leslie-Gower predator-prey model with Allee effect II, affecting the functional response with the assumption that the extent to which the environment provides protection to both predator and prey is the same. The model has been studied analytically as well as numerically, including stability and bifurcation analysis. Compared with the predator-prey model without Allee effect, it is found that the weak Allee effect II can bring rich and complicated dynamics, such as the model undergoes to a series of bifurcations (Homoclinic, Hopf, Saddle-node and Bogdanov-Takens). The existence of Hopf bifurcation has been shown for models with (without) Allee effect and the local existence and stability of the limit cycle emerging through Hopf bifurcation has also been studied. The phase portrait diagrams are sketched to validate analytical and numerical findings

Qualitative Analysis of a Modified Leslie-Gower Predator-prey Model with Weak Allee Effect II

The article aims to study a modified Leslie-Gower predator-prey model with Allee effect II, affecting the functional response with the assumption that the extent to which the environment provides protection to both predator and prey is the same. The model has been studied analytically as well as numerically, including stability and bifurcation analysis. Compared with the predator-prey model without Allee effect, it is found that the weak Allee effect II can bring rich and complicated dynamics, such as the model undergoes to a series of bifurcations (Homoclinic, Hopf, Saddle-node and Bogdanov-Takens). The existence of Hopf bifurcation has been shown for models with (with- out) Allee effect and the local existence and stability of the limit cycle emerging through Hopf bifurcation has also been studied. The phase portrait diagrams are sketched to validate analytical and numerical findings

The Impact of Nonlinear Harvesting on a Ratio-dependent Holling-Tanner Predator-prey System and Optimum Harvesting

In this paper, a Holling-Tanner predator-prey model with ratio-dependent functional response and non-linear prey harvesting is analyzed. The mathematical analysis of the model includes existence, uniqueness and boundedness of positive solutions. It also includes the permanence, local stability and bifurcation analysis of the model. The ratio-dependent model always has complex dynamics in the vicinity of the origin; the dynamical behaviors of the system in the vicinity of the origin have been studied by means of blow up transformation. The parametric conditions under which bionomic equilibrium point exist have been derived. Further, an optimal harvesting policy has been discussed by using Pontryagin maximum principle. The numerical simulations have been presented in support of the analytical findings

Factors Influencing Adoption of Open Source Software - An Exploratory Study

Open Source Software (OSS), an example of an IS innovation, provides an alternative to proprietary software for organizations. Despite its free availability, OSS has not been universally adopted. While IS innovation has been extensively studied, there is a dearth of research literature on the adoption of OSS. Using a multi-site case study research method and a well known framework on the adoption of IS innovations, we explore this novel phenomenon and uncover critical factors that influence the adoption of OSS in organizations

Supply Chain Management System in Indian Pharmaceutical Industries: Strategies and Best Practices

The Indian Pharmaceutical Industry incurs almost one third of its total cost from supply chain management systems. The SCM costs are relatively higher in India than other countries of the world amounting to 13 % of India’s GDP (Adhikari & Bora ,2014). For having an effective supply chain management system, it is required to have procurement of raw materials, raw materials turned into finished good and then further moved out in market for distribution. The major aspect in relation to SCM is the lack of knowledge on the various SCM related issues and strategies, most of the industries spend a lot of amount on the SCM issues and high resentment is on one specific problem i.e. of reduction in operational cost. However, the effectiveness also depends on SCM to be indispensable in maintaining expenses and seek ways to reduce cost thereby increasing the sales of the company. The purpose of the study is to explore various strategies and best practices involved which are used by the Indian business leaders of Pharma industries and finding out ways to maximize sourcing, distribution, inventory and its management. The methodology used is a single case study on various aspects with the semi- structured interview to collect data. The research design used on data sources identified were: observations, semi-structured Interview and documents of the industry. For the Identification of the challenges and their solutions in SCM strategies the proposed theory of Goldratt’s (1990), Theory of constraints was used as conceptual framework. The results of the study is a significant contribution to the business practices in the industries, increase in supply chain effectiveness, their strength and weakness, reducing organizational operational cost and socially finding the reputation of industries in ensuring the on time availability of their medicines in market. The study also relates, aims in identifying and implementing the best practices in various processes of Supply chain management by facilitating the increased availability, distribution of medicine, profitability and reduced operation cost

Teaching Tip: A Teaching Module Illustrating ERP Item Value Automation

Large parts of the enterprise resource planning (ERP) processes are automated. One example is the item values in the sales order process. To execute a sales order, the ERP system applies a specific “find” strategy on a wide variety of data sources such as customer master, material master, and customer price-specific data tables, and extracts information such as customer class, discounts, and dates for computations of line items, namely, prices, discounts, and taxes. While completing their ERP assignments on the sales order process, students often see only the final sales order amount and ignore—and thereby fail to appreciate and understand—the intricacies of the automated method that executes “behind the scenes” to achieve the sales order numbers. This leaves a gap in students’ learning process, as they treat the ERP automation mechanism as a black box and do not appreciate the finer details of the business process that come into play. To illustrate the general method involved in a business automation process, we have developed a teaching technique where students—without the use of ERP software—complete a sales order by manually searching for values in a sequence based on the business processing logic. This task helps students understand and appreciate the internal processes of business automation in ERP systems

Performance Outcomes of Test-Driven Development: An Experimental Investigation

Despite the growing popularity of test-driven development (TDD), there is no empirical confirmation of the benefits that this contemporary practice confers on its users. Prior research findings on its efficacy have largely been inconclusive. We conducted a laboratory experiment to assess the impact of TDD on software quality and task satisfaction. Additionally, we investigated the productivity aspect of TDD as compared to the traditional test-last method of software development. Results indicate that software quality and task satisfaction are significantly improved when TDD is used. Despite the additional requirements of testing, TDD is not more resource intensive than the test-last method. We also examined TDD’s impact on learning post hoc and discuss the implications of our findings and directions for future research