Browsing by Author "Anupama Sharma"

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A mathematical model for control of vector borne diseases through media campaigns
(2013) A.K. Misra; Anupama Sharma; Jia Li
Vector borne diseases spread rapidly in the population. Hence their control intervention must work quickly and target large area as well. A rational approach to combat these diseases is mobilizing people and making them aware through media campaigns. In the present paper, a non-linear mathematical model is proposed to assess the impact of creating awareness by the media on the spread of vector borne diseases. It is assumed that as a response to awareness, people will not only try to protect themselves but also take some potential steps to inhibit growth of vectors in the environment. The model is analyzed using stability theory of differential equations and numerical simulation. The equilibria and invasion threshold for infection i.e., basic reproduction number, has been obtained. It is found that the presence of awareness in the population makes the disease invasion dificult. Also, continuous efforts by the media along with the swift dissemination of awareness can completely eradicate the disease from the system.
Backward bifurcation in a smoking cessation model with media campaigns
(Elsevier Inc., 2015) Anupama Sharma; A.K. Misra
Nowadays, most of the public policies to manage the social issues are focusing on motivating people via media campaigns. In view of this, we propose and analyze a nonlinear mathematical model to study the effect of media campaigns on smoking cessation. The equilibria of the model have been obtained and their stability discussed. Using center manifold reduction theory, we reduce the proposed model to a system of lower dimension. The reduced system contains all the necessary information regarding the asymptotic behavior of small solutions of the original system. The analysis shows that on changing one parameter of the system (reproduction number, R, which depends on various other parameters), two different manifolds of fixed points cross each other and transcritical bifurcation occurs. Further, for large value of relapse rate the bifurcation is subcritical (backward). This shows that requirement R<1 is only necessary, but not sufficient, for smoking cessation. Numerical simulation also supports the analytically obtained results. © 2014 Elsevier Inc.
Capturing the interplay between malware and anti-malware in a computer network
(2014) A.K. Misra; Maitri Verma; Anupama Sharma
In an era with affluence of local area networks, the recurrent attacks of viruses and other malicious objects are undoubtedly an intruding threat. These malicious objects spread quickly through an unprotected network, corrupt the data and harm the nodes. To comprehend this problem and its plausible solutions more thoroughly, we have proposed and analyzed a mathematical model by considering a network in which nodes are either infected or prone to it. It is considered that nodes vulnerable to infection become infected, when attacked by malicious objects present in the network. To minimize the abundance of malicious objects and infected nodes, some anti-malware softwares are installed in the network, which are continuously being updated. On analyzing the proposed model, we obtained two equilibria and a threshold governing the dynamics of malicious objects in a computer network. The characterization of stability behavior of obtained equilibria is also discussed in detail. The numerical simulation illustrates the validity of analytically obtained results. © 2013 Elsevier Inc. All rights reserved.
Effect of awareness programs in controlling the prevalence of an epidemic with time delay
(2011) A.K. Misra; Anupama Sharma; Vishal Singh
A nonlinear mathematical model with delay to capture the dynamics of effect of awareness programs on the prevalence of any epidemic is proposed and analyzed. It is assumed that pathogens are transmitted via direct contact between susceptibles and infectives. It is assumed further that cumulative density of awareness programs increases at a rate proportional to the number of infectives. It is considered that awareness programs are capable of inducing behavioral changes in susceptibles, which result in the isolation of aware population. The model is analyzed using stability theory of differential equations and numerical simulations. The model analysis shows that, though awareness programs cannot eradicate infection, they help in controlling the prevalence of disease. It is also found that time delay in execution of awareness programs destabilizes the system and periodic solutions may arise through Hopf-bifurcation. © 2011 World Scientific Publishing Company.
Modeling and analysis of effects of awareness programs by media on the spread of infectious diseases
(2011) A.K. Misra; Anupama Sharma; J.B. Shukla
In this paper, a non-linear mathematical model for the effects of awareness programs on the spread of infectious diseases such as flu has been proposed and analyzed. In the modeling process it is assumed that disease spreads due to the contact between susceptibles and infectives only. The growth rate of awareness programs impacting the population is assumed to be proportional to the number of infective individuals. It is further assumed that due to the effect of media, susceptible individuals form a separate class and avoid contact with the infectives. The model is analyzed by using stability theory of differential equations. The model analysis shows that the spread of an infectious disease can be controlled by using awareness programs but the disease remains endemic due to immigration. The simulation analysis of the model confirms the analytical results. © 2010 Elsevier Ltd.
Modeling the impact of awareness created by media campaigns on vaccination coverage in a variable population
(World Scientific Publishing Co. Pte Ltd, 2014) Anupama Sharma; A.K. Misra
Vaccines are a core component of any preventive strategy designed to ensure the global public health. A major factor influencing the successful implementation of any immunization program is awareness and public acceptance of the vaccine. The present study focuses on potential impacts of awareness created by media campaigns on vaccination coverage of hepatitis B. In this paper, a SIR model with vital dynamics in a population of varying size is investigated, which couples hepatitis B vaccination and awareness created by media within a single framework. It is assumed that media campaigns propagate awareness about measures requisite for escaping the chances of contracting hepatitis B. The awareness created by media motivates people to get vaccinated and attain full immunization against hepatitis B virus. For analyzing the model, stability theory of differential equations is employed. First, equilibria of the system comprising fractions of the population are obtained and their stability behavior is discussed. Then the asymptotic behavior of total population is discussed in detail. Three threshold parameters R0, R1 and R2 governing the dynamics of infection and total population are also affirmed. The findings of numerical simulations are also in line with analytically obtained results. © 2014 World Scientific Publishing Company.
Monitoring long-term storage of CO2 in a gas and condensate field in the North Sea off the coast of Norway using seismic methods
(Society of Exploration Geophysicists, 2025) Ajay Pratap Singh; Satya Prakash Maurya; Ravi Kant; Brijesh M.N. Kumar; Gopal Hema; Manoj Kumar Srivastava; Abhay Kumar; Anjali; Shoharat; Rohit Chaurasia; Anupama Sharma; Ankita Devi; Swarnima Pandey
The rising concentration of CO2 in the atmosphere drives climate change, prompting the development of various mitigation strategies. One approach involves injecting CO2 into hydrocarbon reservoirs for long-term storage. For long-term storage, one needs to monitor the injected CO2 to see the CO2 storage location and detect any leakage. This study focuses on the monitoring of injected CO2 in the Utsira Formation from a gas and condensate field in the Sleipner Field off the coast of Norway. The monitoring of injected CO2 is carried out using seismic inversion techniques of time-lapse data acquired over the injected zone at different time intervals. Seismic inversion techniques transform seismic reflection data into quantitative acoustic impedance models of the subsurface. The objective of the present study is to compare model-based inversion, band-limited inversion (BLI), maximum likelihood inversion, linear programming inversion (LPI) and sparse layer reflectivity inversion (SLRI) approaches to monitor CO2. All inversion techniques show consistent results, with low impedance values ranging from 2115 to 5275 m/s*g/cm3 in the Utsira Formation. Among these techniques, SLRI and LPI outperform traditional methods by offering high-resolution imaging of CO2 migration pathways, making them particularly effective for early leak detection and reducing uncertainties in reservoir modeling. By enhancing storage security and predictive modeling, these methodologies significantly contribute to the scalability and reliability of carbon capture and storage as a critical tool in combating climate change. This research not only strengthens the scientific foundation of seismic monitoring techniques but also provides practical recommendations for optimizing subsurface CO2 storage assessment methods. © 2025 Society of Exploration Geophysicists. All rights reserved.
Spatio-temporal patterns in a cholera transmission model
(World Scientific, 2015) A.K. Misra; Milan Tiwari; Anupama Sharma
Cholera has been a public health threat for centuries. Unlike the biological characteristics, relatively less effort has been paid to comprehend the spatial dynamics of this disease. Therefore, in this paper, we have proposed a cholera epidemic model for variable population size and studied the spatial patterns in two-dimensional space. First, we have performed the equilibrium and local stability analysis of steady states obtained for temporal system. Afterwards, the local and global stability behavior of the endemic steady state in a spatially extended setting has been investigated. The numerical simulations have been done to investigate the spatial patterns. They show that dynamics of the cholera epidemic varies with time and space. © 2015 World Scientific Publishing Company.
Stability analysis and optimal control of an epidemic model with awareness programs by media
(Elsevier Ireland Ltd, 2015) A.K. Misra; Anupama Sharma; J.B. Shukla
The impact of awareness campaigns and behavioral responses on epidemic outbreaks has been reported at times. However, to what extent does the provision of awareness and behavioral changes affect the epidemic trajectory is unknown, but important from the public health standpoint. To address this question, we formulate a mathematical model to study the effect of awareness campaigns by media on the outbreak of an epidemic. The awareness campaigns are treated as an intervention for the emergent disease. These awareness campaigns divide the whole populations into two subpopulation; aware and unaware, by inducing behavioral changes amongst them. The awareness campaigns are included explicitly as a separate dynamic variable in the modeling process. The model is analyzed qualitatively using stability theory of differential equations. We have also identified an optimal implementation rate of awareness campaigns so that disease can be controlled with minimal possible expenditure on awareness campaigns, using optimal control theory. The control setting is investigated analytically using optimal control theory, and the numerical solutions illustrating the optimal regimens under various assumptions are also shown. © 2015 Elsevier Ireland Ltd.
Surface modified PAMAM dendrimers with gallic acid inhibit, cell proliferation, cell migration and inflammatory response to augment apoptotic cell death in human colon carcinoma cells
(Taylor and Francis Ltd., 2021) Khushbu Priyadarshi; Kavita Shirsath; N. Bhargav Waghela; Anupama Sharma; Ajay Kumar; Chandramani Pathak
To overcome the obstacle of anti-cancer therapy significant attention has been drawn for improving drug delivery system. Since recent past, different approaches were applied using synthetic or natural derivatives for improving efficacy of anti-cancer drugs in cancer therapeutics. Gallic acid (GA) is a natural polyphenol, which exhibits a broad spectrum of biological activities, but its therapeutic application was limited due to poor bioavailability and toxicity. In the present study, we had conjugated the GA with PAMAM dendrimers and proposed the insights of molecular mechanism on inhibition of cell proliferation and programmed cell death through apoptotic pathway in human colon carcinoma cells. GA was chemically conjugated with 4.0 G PAMAM dendrimer at outer surface and characterized by different biophysical methods. We further examined its bioavailability, anti-cancer activity and explored the molecular mechanism of programmed cell death signaling in HCT116 cells. The results show that PAMAM-GA conjugate inhibits cell proliferation of different origin of cancer cells, improves cellular uptake of GA, inhibits colonogenic ability, restricts cancer cell migration by down regulating the expression of MMP-9, inhibits NF-kB activation and release of pro-inflammatory cytokines to manifest apoptotic cell death in HCT 116 cells rather than necrosis. On other hand, PAMAM-GA conjugate showed negligible cytotoxic response as compared to the free Gallic acid to the normal cells. In conclusion, findings of this study revealed that PAMAM-GA conjugate improves the bioavailability of GA and specificity towards cancer cellsto manifests apoptotic cell death. This indispensable approach may be beneficial for the revolution of anti-cancer therapy. Communicated by Ramaswamy H. Sarma. © 2020 Informa UK Limited, trading as Taylor & Francis Group.