One of the key advantages of Wireless Mesh Networks (WMNs) is their importance for providing cost-efficient broadband connectivity. There are issues for achieving the network connectivity and user coverage, which are related with the node placement problem. We implemented a simulation system where we consider the router node placement problem in WMNs. We want to find the optimal distribution of router nodes in order to provide the best network connectivity and provide the best coverage in a set of randomly distributed clients. We modeled 3 different realistic distribution of mesh clients (Subway, Boulevard and Stadium models). From simulation results, we found that, in the case of Subway model distribution of mesh clients, connectivity and coverage reach maximum performance. For all 3 models, when the instance size increases, the performance decreases.
-This paper proposes an evolved architecture from 3G networks to provide basic and advanced positioning methods for Location Based Services in Mobile IPv6-based Radio Access Networks. We start analyzing current status of Location-Based Services (i.e. LBS or LCS) and architectures in 3G networks as well as state-of-the-art research on LBS and Mobile Internet. Next we set the requirements the solution should fulfill. We continue proposing the evolved architecture for support of basic and advanced positioning methods, using MIPv6 and HMIPv6 as mobility scenario for the Mobile IPv6 based RAN, describing element's functions and changes from current approaches as well as description of the dynamic behavior. We complete the proposal with a bandwidth analysis of the signaling, identifying issues when planning implementation of LCS services in the network.
Background
Several countries have recently reported the detection of ESBL-producing Shigella sonnei associated with transmission among MSM. In a previous study by our group, 2.8% of Shigella spp. obtained from MSM in Barcelona between 2015 and 2019 were ESBL producers.
Objectives
To describe and characterize the emerging ESBL-producing Shigella spp. associated with sexual transmission among MSM detected from 2020 to 2021 in Barcelona, elucidating their connectivity with contemporaneous ESBL-producing Shigella spp. from other countries.
Results
From 2020 to 2021, we identified that among MSM, 68% of S. sonnei were XDR harbouring blaCTX-M-27 and 14% of Shigella flexneri were MDR harbouring blaCTX-M-27. WGS analysis showed that the ESBL-producing S. sonnei were part of a monophyletic cluster, which included isolates responsible for the prolonged outbreak occurring in the UK. Our data also reveal the first emergence and clonal dissemination of ESBL-producing and fluoroquinolone-resistant S. flexneri 2a among MSM.
Conclusions
We report an increasing trend of antimicrobial resistance in Shigella spp. among MSM in Barcelona since 2021, mainly as a consequence of the dissemination of XDR ESBL-producing S. sonnei, previously reported in the UK. These results highlight the importance of international collaborative surveillance of MDR/XDR S. sonnei and S. flexneri for rapid identification of their emergence and the prevention of the transmission of these pathogens.
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