122 research outputs found

    A low complexity resource allocation algorithm for multicast service delivery in OFDMA networks

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    Allocating and managing radio resources to multicast transmissions in Orthogonal Frequency-Division Multiple Access (OFDMA) systems is the challenging research issue addressed by this paper. A subgrouping technique, which divides the subscribers into subgroups according to the experienced channel quality, is considered to overcome the throughput limitations of conventional multicast data delivery schemes. A low complexity algorithm, designed to work with different resource allocation strategies, is also proposed to reduce the computational complexity of the subgroup formation problem. Simulation results, carried out by considering the Long Term Evolution (LTE) system based on OFDMA, testify the effectiveness of the proposed solution, which achieves a near-optimal performance with a limited computational load for the system

    Using a distributed Shapley-value based approach to ensure navigability in a social network of smart objects

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    The huge number of nodes that is expected to join the Internet of Things in the short term will add major scalability issues to several procedures. A recent promising approach to these issues is based on social networking solutions to allow objects to autonomously establish social relationships. Every object in the resulting Social IoT (SIoT) exchanges data with its friend objects in a distributed manner to avoid the need for centralized solutions to implement major functionalities, such as: node discovery, information search and trustworthiness management. However, the number and types of established friendship affects network navigability. This paper addresses this issue proposing an efficient, distributed and dynamic strategy for the objects to select the right friends for the benefit of the overall network connectivity. The proposed friendship selection model relies on a Shapley-value based algorithm mapping the friendship selection process in the SIoT onto the coalition formation problem in a corresponding cooperative game. The obtained results show that the proposed solution is able to ensure global navigability, measured in terms of average path length among two nodes in the network, by means of a distributed and wise selection of the number of friend objects a node has to handle

    Gateway Discovery and Selection in Mobile Hotspots

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    Gaining IP connectivity in mobile hotspots (e.g. public transport vehicles) through on-board local area networks and mobile gateways has recently attracted strong commercial and research interests. In this paper we propose a multi-dimensional protocol to support the process of gatewaydiscovery in mobile hotspots, and to help in selecting the best path able to satisfy the user's requirements and to guarantee a target end-to-end service quality. Our proposal is based on highly popular and almost standard protocols, such as SDPng for session description and AODV for route discovery

    Persistent systemic microbial translocation, inflammation, and intestinal damage during Clostridioides difficile infection

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    Background. Clostridioides difficile infection (CDI) might be complicated by the development of nosocomial bloodstream infection (n-BSI). Based on the hypothesis that alteration of the normal gut integrity is present during CDI, we evaluated markers of microbial translocation, inflammation, and intestinal damage in patients with CDI. Methods. Patients with documented CDI were enrolled in the study. For each subject, plasma samples were collected at T0 and T1 (before and after CDI therapy, respectively), and the following markers were evaluated: lipopolysaccharide-binding protein (LPB), EndoCab IgM, interleukin-6, intestinal fatty acid binding protein (I-FABP). Samples from nonhospitalized healthy controls were also included. The study population was divided into BSI+/BSI- and fecal microbiota transplantation (FMT) +/FMT- groups, according to the development of n-BSI and the receipt of FMT, respectively. Results. Overall, 45 subjects were included; 8 (17.7%) developed primary n-BSI. Markers of microbial translocation and intestinal damage significantly decreased between T0 and T1, however, without reaching values similar to controls (P < .0001). Compared with BSI-, a persistent high level of microbial translocation in the BSI+ group was observed. In the FMT+ group, markers of microbial translocation and inflammation at T1 tended to reach control values. Conclusions. CDI is associated with high levels of microbial translocation, inflammation, and intestinal damage, which are still present at clinical resolution of CDI. The role of residual mucosal perturbation and persistence of intestinal cell damage in the development of n-BSI following CDI, as well as the possible effect of FMT in the restoration of mucosal integrity, should be further investigated

    Early Warning Systems for Emerging Profiles of Antimicrobial Resistance in Italy: A National Survey

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    Antimicrobial resistance (AMR) national surveillance systems in Italy lack alert systems for timely detection of emerging profiles of AMR with potential relevance to public health. Furthermore, the existence of early warning systems (EWS) at subnational level is unclear. This study aims at mapping and characterizing EWS for microbiological threats available at regional level in Italy, focusing on emerging AMR, and at outlining potential barriers and facilitators to their development/implementation. To this end, a three-section, web-based survey was developed and administered to all Italian regional AMR representatives from June to August 2022. Twenty out of twenty-one regions and autonomous provinces (95.2%) responded to the survey. Among these, nine (45%) reported the implementation of EWS for microbiological threats at regional level, three (15%) reported that EWS are in the process of being developed, and eight (40%) reported that EWS are not currently available. EWS characteristics varied widely among the identified systems concerning both AMR profiles reported and data flow: the microorganisms most frequently included were extensively drug-resistant (XDR) Enterobacterales, with the lack of a dedicated regional IT platform reported in most cases. The results of this study depict a highly heterogeneous scenario and suggest that more efforts aimed at strengthening national AMR surveillance systems are needed

    Does immediate breast reconstruction after mastectomy and neoadjuvant chemotherapy influence the outcome of patients with non-endocrine responsive breast cancer?

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    Background/Aim: In breast cancer (BC) patients, breast surgery followed by immediate breast reconstruction (IBR) might favour recurrences and metastases due to extensive surgical manipulation. We retrospectively investigated whether IBR after mastectomy and neoadjuvant chemotherapy (NT) influenced the outcome in patients with early and locally advanced oestrogen receptor (ER)-negative BC. Patients and Methods: Between 1995 and 2006, 133 BC patients received NT followed by total mastectomy, 59 of whom underwent IBR. Patients receiving IBR (IBR group) were compared to patients who did not receive IBR (no-IBR group) over a prolonged median follow-up time (8.2 years). Results: Patients receiving IBR were on average younger than patients not receiving IBR (p<0.00I). The percentage of patients with positive clinical nodal status (cN) was 19% in the IBR group and 7% in no-IBR group (p=0.036), whereas patients without 1BR were more frequently diagnosed as clinical T4 (59% vs. 15%, p<0.001). The 5-year cumulative incidence of locoregional recurrences were 14% in the no-IBR group and 21% in the IBR group. The hazard of locoregional events, adjusted for age, clinical T and cN, was significantly greater in the IBR group than in the no-IBR group (hazard ratio (HR)=2.77, p=0.045). The 5-year cumulative incidences of distant metastases were similar in the two groups (p=0.414). Conclusion: IBR following total mastectomy in patients with ER-negative disease after NT is associated with a worse rate of local relapses. More insight in mechanisms of wound healing and extent of surgery is required to further investigate this observation

    Controlled Load Services in IP QoS Geostationary Satellite Networks

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