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A deterministic model for the transmission of two-strain typhoid fever is developed. The aim is to predict the influence of the typhoid conjugate vaccine on the prevalence of antimicrobial-resistant typhoid infection. Two mechanisms of antimicrobial resistance are incorporated in the model, namely treatment-induced/acquired resistance and transmission of resistant S. Typhi strain. The mathematical analysis is performed using both analytical and numerical approaches. The results show that the disease-free state is locally asymptotically stable if the effective reproduction number ${{ℛ}}_e$ is less than unity. Further analysis reveals that the model exhibits vaccine-induced backward bifurcation, suggesting that ${{ℛ}}_e<1$ is not sufficient for disease elimination. Furthermore, numerical simulations have shown that the existence of endemic equilibrium depends on the sign of ${{ℛ}}_e^r-{{ℛ}}_e^s$. Here, ${{ℛ}}_e^r$ and ${{ℛ}}_e^s$ denote the effective reproduction numbers for the resistant and sensitive strains, respectively. When $\varphi >0$, where $\varphi$ is the rate of treatment-induced/acquired resistance, the resistant strain will cause the extinction of the sensitive strain if ${{ℛ}}_e^r>{{ℛ}}_e^s$. However, the two strains co-exist if ${{ℛ}}_e^r\le {{ℛ}}_e^s$. When $\varphi =0$, the co-existence equilibrium exists if ${{ℛ}}_e^s={{ℛ}}_e^r$; otherwise, the strain with a higher reproduction number would cause the other strain to become extinct, showing the competitive exclusion of the two competing strains. Moreover, the sensitivities of various parameters on the fraction of AMR infections are demonstrated. Also, the prevalence of typhoid decreases with the increase in the number of vaccinated individuals, but vaccination alone is unlikely to control the AMR typhoid infection. The study suggests that more preventive interventions need to be implemented to effectively control antimicrobial-resistant typhoid infections.

A new ultra wideband (UWB) pulse shape is proposed to mitigate coexistence issues of IEEE802.11.a WLAN and impulse radio UWB (IR-UWB) systems. The proposed method is applicable to the reduction of mutual interference of UWB and any given narrowband (NB) systems. This pulse shape is based on frequency up-converting of the first derivative of the Gaussian pulse which has an adjustable null in power spectral density (PSD) depending on the up-converting frequency. Analytical and simulation results show that both UWB and WLAN systems have noticeable improved performance when using the proposed pulse in comparison with using conventional modulated Gaussian (MG) pulse in UWB system. The new pulse does not reduce the throughput of the UWB system and does not require modification of the NB system. The proposed transmitter circuit block diagram has been presented at the conclusion.

Toxic or allelopathic compounds liberated by toxin-producing phytoplankton (TPP) acts as a strong mediator in plankton dynamics. On an analysis of a set of phytoplankton biomass data that have been collected by our group in the northwest part of the Bay of Bengal, and by analysis of a three-component mathematical model under a constant as well as a stochastic environment, we explore the role of toxin-allelopathy in determining the dynamic behavior of the competing phytoplankton species. The overall results, based on analytical and numerical wings, demonstrate that toxin-allelopathy due to the TPP promotes a stable co-existence of those competitive phytoplankton that would otherwise exhibit competitive exclusion of the weak species. Our study suggests that TPP might be a potential candidate for maintaining the co-existence and diversity of competing phytoplankton species.

Wireless Body Area Networks (WBANs) are envisioned as a key enabling technology for the next-generation pervasive healthcare systems. Characterized by limited energy and computational resources, inter-user interference deteriorates reliable data transmission when multiple WBANs are transmitting simultaneously on the same channel in close proximity, making it one of the greatest challenges. In this paper, we propose a novel distributed adaptive scheduling scheme to reduce interference among co-existing WBANs. The basic idea of this scheduling scheme is to avoid the overlap of active beacon period of neighboring WBANs. The performance of the proposed scheme was compared with schemes based on IEEE 802.15.6 using an OMNET++ simulator. Simulation results show that the proposed scheme performs better in terms of packet delivery ratio, energy consumption and delivery latency than the schemes based on IEEE 802.15.6.