Synchronized Tick Population Oscillations Driven by Host Mobility and Spatially Heterogeneous Developmental Delays Combined

We consider a coupled system of delay differential equations for a single-species tick population dynamics, assuming feeding adult ticks are distributed by their hosts in a spatially heterogeneous environment consisting of two patches where egg ticks produced will complete their life cycles with different, normal and diapause, developmental delays. We show that the mobility of adult tick host and the diapause developmental delay combined drive a synchronized oscillation in the total tick populations around a uniquely defined positive equilibrium, and this synchronization makes the oscillatory patterns much simpler in comparison with multi-peak oscillations exhibited in the absence of host mobility.

Multiple drivers of the COVID-19 spread: role of climate, international mobility, and region-specific conditions

The novel Coronavirus Disease 2019 (COVID-19) has spread quickly across the globe. Here, we evaluated the role of climate (temperature and precipitation), region-specific susceptibility (BCG vaccination, malaria infection, and elderly population) and international traveller population (human mobility) in shaping the geographical patterns of COVID-19 cases across 1,055 countries/regions, and examined the sequential shift of multiple drivers of the accumulated cases from December, 2019 to April 12, 2020. The accumulated numbers of COVID-19 cases (per 1 million population) were well explained by a simple regression model. The explanatory power (R2) of the model increased up to > 70% in April 2020 as the COVID-19 spread progressed. Climate, host mobility, and host susceptibility largely explained the variance of the COVID-19 cases (per 1 million population), and their explanatory power improved as the pandemic progressed; the relative importance of host mobility and host susceptibility have been greater than that of climate. The number of days from outbreak onset showed greater explanatory power in the earlier stages of COVID-19 spread but rapidly lost its influence. Our findings demonstrate that the COVID-19 pandemic is deterministically driven by climate suitability, cross-border human mobility, and region-specific susceptibility. The present distribution of COVID-19 cases has not reached an equilibrium and is changing daily, especially in the Southern Hemisphere. Nevertheless, the present results, based on mapping the spread of COVID-19 and identifying multiple drivers of this outbreak trajectory, may contribute to a better understanding of the COVID-19 disease transmission risk and the measures against long-term epidemic.

Performance Parameter of AODV and DSR Potocol by Varying Nodes Mobility

MANET is a cluster of nodes that are mobile which transfer the packet within a limited transmission range. It is decentralized and infrastructure less wireless network. Due to host mobility requirement for a robust dynamic routing protocol is needed, since a random and dynamic difference in the network topology is there. This paper presents a performance analysis between two routing protocols AODV and DSR. In terms of throughput, PDR and delay both protocols AODV and DSR is compared.

Multicast Communication Using Different Group Key Managements

The most appropriate communication mechanism for transfer of packets from one source to another is multicast IPv6 communication. Nowadays, multicast communication plays a major role in a large number of communication applications. In this multicast communication, the message privacy attains a highest position. The members of multicast are dynamic so they permit the host members to enter and depart the cluster without the permission of remaining group members and, it can't provide any transfer without the interference of host, this may reduce the performance. For security enhancement in multicast communication Group Key Management (GKM) was introduced. There are three different approaches in GKM and they were mainly involved to overcome the issues of host mobility in multicast communication. The challenges that are encountered by these GKM approaches their requirements and challenges was also discussed in this paper. Finally, some questions and their explanations were provided along with it. These GKM approaches will improve the privacy of multicast communication. So, the packets can deliver to the group members without any interference.