ABSTRACT
The SARS-CoV-2 driven infectious novel coronavirus disease (COVID-19) has been declared a pandemic by its brutal impact on the world in terms of loss on human life, health, economy, and other crucial resources. To explore more about its aspects, we adopted the S E I R D (Susceptible-Exposed-Infected-Recovered-Death) pandemic spread with a time delay on the heterogeneous population and geography in this work. Focusing on the spatial heterogeneity, epidemic spread on the framework of modeling that incorporates population movement within and across the boundaries is studied. The entire population of interest in a region is divided into small distinct geographical sub regions, which interact using migration networks across boundaries. Utilizing the time delay differential equations based model estimations, we analyzed the spread dynamics of disease in India. The numerical outcomes from the model are validated using real time available data for COVID-19 cases. Based on the developed model in the framework of the recent data, we verified total infection cases in India considering the effect of nationwide lockdown at the onset of the pandemic and its unlocking by what seemed to be the end of the first wave. We have forecasted the total number of infection cases in two extreme situations of nationwide no lockdown and strict lockdown scenario. We expect that in future for any change in the key parameters, due to the regional differences, predictions will lie within the bounds of the above mentioned extreme plots. We computed the approximate peak infection in forwarding time and relative timespan when disease outspread halts. The most crucial parameter, the time-dependent generalization of the basic reproduction number, has been estimated. The impact of the social distancing and restricted movement measures that are crucial to contain the pandemic spread has been extensively studied by considering no lockdown scenario. Our model suggests that attaining a reduction in the contact rate between susceptible and infected individuals by practicing strict social distancing is one of the most effective control measures to manage COVID-19 spread in India. The cases can further decrease if social distancing is followed in conjunction with restricted movement.
ABSTRACT
Connectivity and rates of movement have profound effect on the persistence and extinction of infectious diseases. The emerging disease spread rapidly, due to the movement of infectious persons to some other regions, which has been witnessed in case of novel coronavirus disease 2019 (COVID-19). So, the networks and the epidemiology of directly transmitted infectious diseases are fundamentally linked. Motivated by the recent empirical evidence on the dispersal of infected individuals among the patches, we present the epidemic model SEIR (Susceptible-Exposed-Infected-Recovered) in which the population is divided into patches which form a network and the patches are connected through mean-field diffusive coupling. The corresponding unstable epidemiology classes will be synchronized and achieve stable state when the patches are coupled. Apart from synchronization and stability, the coupled model enables a range of rhythmic processes such as birhythmicity and rhythmogenesis which have not been investigated in epidemiology. The stability of Disease Free Equilibrium (or Endemic Equilibrium) is attained through cessation of oscillation mechanism namely Oscillation Death (OD) and Amplitude Death (AD). Corresponding to identical and non-identical epidemiology classes of patches, the different steady states are obtained and its transition is taking place through Hopf and transcritical bifurcation.
ABSTRACT
BACKGROUND: A major concern and challenge faced by the educational institution during coronavirus disease (COVID-19) pandemic and consequent lockdown is the timely conduct of the summative assessment. Unlike cognitive assessment, real-time practical assessment through online mode, without compromising principles of assessment is difficult. This study was performed to analyze an alternative hybrid approach adopted for the postgraduate practical summative assessment in pathology. MATERIALS AND METHODS: Evaluation of the process of summative assessment was done where internal and external examiners synchronously assessed examinees real-time on-site (face to face) and off-site (remotely through live videoconferencing) respectively. A pre-validated questionnaire on a novel approach for assessment and feedback (with close-ended on 5-point Likert scale and open-ended questions) were administered to nine participants comprising three final year postgraduates in pathology, four examiners (two internal and two externals) and two technical experts from the Department of Pathology. Overall scores obtained by all examinees were recorded. A pre-validated questionnaire and feedback were administered to the participants to assess the novel approach to assessment. RESULTS: The mean performance score obtained by examinees was 63.5% in the summative assessment. Feedback analysis revealed that 85% of participants strongly agreed and the rest (15%) agreed that essential minor deviations introduced in this novel mode of assessment did not compromise basic principles and goals of assessment. Quality of assessment through this mode of assessment was graded as good to excellent. All participants responded that this mode of examination may be applied in the future under similar circumstances. CONCLUSION: This study concludes that an alternative novel hybrid method of real-time synchronous assessment with on-site and off-site examiners may be a feasible and successful model for conducting summative assessment and can be practiced in time of need.