Resource Allocation in Communications Networks Using Market-Based Agents

The work in this thesis describes a system that allocates the end-to-end bandwidth, in a meshed communications network, to set up calls. The solution makes use of market-based software agents that compete in a number of decentralised market-places in order to buy and sell bandwidth. The network is partitioned into regions, where each has a separate market server from where the bandwidth resources are allocated. Agents perform a distributed search with decentralised markets in order to allocate routes for calls. The approach relies on a resource reservation and commit mechanism in the network. Results show that for a typical network given a light load, the system sets up 95% of calls and is comparable in performance to an instantaneous global search, which assumes complete knowledge of resource availability and sets up 97% of calls at the same load. As the network load is increased to a typical intermediate level, the system gives an average call success rate which is 76% of that given by the instantaneous global search. Furthermore, under all network loads, the system performs significantly better than a random strategy. We also consider issues associated with scalability and robustness in our multi-agent system. Specifically, an empirical evaluation was carried out to assess the system performance under a variety of design configurations in order to provide an insight into network deployment issues. This took place using networks that were fixed in size but which were scaled up with respect to the number of regions and, hence, market servers. We investigated two main measures: the average call success rate and average message load per market server, as the number of markets were increased in the network. The same investigations were performed in the presence of single market failures. For both the failure and non-failure cases, a trade-off was found between the two measures to find an optimum number of regions to deploy in the network. In general, results showed that in the absence of failures, fewer regions gave a higher average call success rate and more regions meant that, on average, market servers received less messages per market server, when searching for resources across a single regional route. With a single market failure, we saw that when more regions were deployed, in general, the average call success rate was higher up to a certain point and the number of messages received per market server was lower, when also using a single regional route. In the final part of this thesis, we make a change to part of our original algorithm in order to try and improve upon the system performance. To overcome the need for receiving fewer messages per market server and having quicker call set up times, we allow buyer agents to bid for resource bundles that lead to several boundary nodes in a region, in a single auction, rather than the possibility of using multiple auctions. Thus, we introduce a multi-destination buyer strategy. By constraining the amount of resource searching in this way, we can see that there are performance trade-offs where call set up times decrease, average call success rates increase in general, but that the system allocates a smaller proportion of longer distance calls than when using the original strategy. We also show that, in general, it is better to search across a single regional route instead of searching across multiple regional routes, particularly when the network load is high. However, at much lighter network loads, searching for resources by means of traversing alternative regions can give a better overall average call success rate

High prevalence of norovirus GII.4 Sydney among children with acute gastroenteritis in Bangladesh, 2018–2021

Background: Active molecular surveillance and rapid diagnosis method to track an outbreak of norovirus in Bangladesh is lacking. This study aims to determine the genotypic diversity, molecular epidemiology and evaluate a rapid diagnosis method. Methods: A total of 404 fecal specimens were collected from children aged below 60 months from January 2018 to December 2021. All samples were analyzed by reverse transcriptase polymerase chain reaction molecular sequencing of partial VP1 nucleotide. Immunochromatography kit (IC, IP Rota/Noro) was evaluated against reference test method. Results: We found norovirus in 6.7 % (27 of 404) fecal specimens. A wide diversity of norovirus genotype including GII.3, GII.4, GII.5, GII.6, GII.7, and GII.9 were detected. Norovirus strain GII.4 Sydney-2012 was the most predominant (74 %, 20 of 27) followed by GII.7 (7.4 %), GII.9 (7.4 %), GII.3 (3.7 %), GII.5 (3.7 %) and GII.6 (3.7 %), respectively. Co-infection of rotavirus and norovirus (19 [4.7 %] of 404) was the most prevalent. We found higher odds of prolonged health impact [OR 1.93 (95 % CI 0.87–3.12) (p = .001)] among patients with co-infection. The incidence of norovirus was significant among the children below 24 months (p = 0.001). Significant relation of temperature with the cases of norovirus was detected (p = 0.001). The IC kit provided high specificity (99.3 %) and sensitivity (100 %) for the detection of norovirus. Conclusions: This study will provide an integrated insight on the genotypic diversity and rapid identification method of norovirus in Bangladesh

MicroRNAs and Tumor Vasculature Normalization: Impact on Anti-Tumor Immune Response

International audiencenefficient immune response is a major glitch during tumor growth and progression. Chaotic and leaky blood vessels created in the process of angiogenesis allow tumor cells to escape and extricate anti-cancer immunity. Proangiogenic characteristics of hypoxic tumor microenvironment maintained by low oxygen tension attract endothelial progenitor cells, drive expansion of cancer stem cells, and deviantly differentiate monocyte descendants. Such cellular milieu further boosts immune tolerance and eventually appoint immunity for cancer advantage. Blood vessel normalization strategies that equilibrate oxygen levels within tumor and fix abnormal vasculature bring exciting promises to future anticancer therapies especially when combined with conventional chemotherapy. Recently, a new group of microRNAs (miRs) engaged in angiogenesis, called angiomiRs and hypoxamiRs, emerged as new therapeutic targets in cancer. Some of those miRs were found to efficiently regulate cancer immunity and their dysregulation efficiently programs aberrant angiogenesis and cancer metastasis. The present review highlights new findings in the field of miRs proficiency to normalize aberrant angiogenesis and to restore anti-tumor immune responses

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit