STORRE Collection: Electronic copies of Computing Science and Mathematics journal articles.
http://hdl.handle.net/1893/216
Electronic copies of Computing Science and Mathematics journal articles.2024-03-23T00:29:02ZOn the non-existence of sympathetic Lie algebras with dimension less than 25
http://hdl.handle.net/1893/35815
Title: On the non-existence of sympathetic Lie algebras with dimension less than 25
Author(s): Garcia Pulido, Ana Lucia; Salgado, Gil
Abstract: In this article we investigate the question of the lowest possible dimension that a sympathetic Lie algebra g can attain, when its Levi subalgebra gL is simple. We establish the structure of the nilradical of a perfect Lie algebra g, as a gL-module, and determine the possible Lie algebra structures that one such g admits. We prove that, as a gL-module, the nilradical must decompose into at least 4 simple modules. We explicitly calculate the semisimple derivations of a perfect Lie algebra g with Levi sub-algebra gL=sl2(C) and give necessary conditions for g to be a sympathetic Lie algebra in terms of these semisimple derivations. We show that there is no sympathetic Lie algebra of dimension lower than 15, independently of the nilradical’s decomposition. If the nilradical has 4 simple modules, we show that a sympathetic Lie algebra has dimension greater or equal than 25.2023-12-08T00:00:00ZModelling norovirus dynamics within oysters emphasises potential food safety issues associated with current testing & depuration protocols
http://hdl.handle.net/1893/35708
Title: Modelling norovirus dynamics within oysters emphasises potential food safety issues associated with current testing & depuration protocols
Author(s): McMenemy, Paul; Kleczkowski, Adam; Taylor, Nick G H
Abstract: Norovirus is a significant global cause of viral gastroenteritis, with raw oyster consumption often linked to such outbreaks due to their filter-feeding in harvest waters. National water quality and depuration/relaying times are often classified using Escherichia coli, a poor proxy for norovirus levels in shellfish. The current norovirus assay is limited to only the digestive tracts of oysters, meaning the total norovirus load of an oyster may differ from reported results. These limitations motivated this work, building upon previous modelling by the authors, and considers the sequestration of norovirus into observed and cryptic (unobservable) compartments within each oyster. Results show that total norovirus levels in shellfish batches exhibit distinct peaks during the early depuration stages, with each peak's magnitude dependent on the proportion of cryptic norovirus. These results are supported by depuration trial data and other studies, where viral levels often exhibit multiphase decays. This work's significant result is that any future norovirus legislation needs to consider not only the harvest site's water classification but also the total viral load present in oysters entering the market. We show that 62 h of depuration should be undertaken before any norovirus testing is conducted on oyster samples, being the time required for cryptic viral loads to have transited into the digestive tracts where they can be detected by current assay, or have exited the oyster.2023-12-01T00:00:00ZDeSSR: a Decentralized, Broadcast-Based Scalable Scheduling Reservation Protocol for 6TiSCH Networks
http://hdl.handle.net/1893/35659
Title: DeSSR: a Decentralized, Broadcast-Based Scalable Scheduling Reservation Protocol for 6TiSCH Networks
Author(s): Kumar, Kaushal; Kolberg, Mario
Abstract: The emergence of IPv6 (Internet Protocol Version 6) for low-power wireless communication is considered a breakthrough allowing a densely populated multi-hop network of Internet of Things (IoT) devices to be used for data gathering over a range of 1-2 kilometer (km). However, the communication between the devices has suffered from external interferences and multi-path fading challenge. The Internet Engineering Task Force (IETF) and Institute of Electrical and Electronics Engineers (IEEE) jointly proposed The IPv6 over IEEE 802.15.4 TSCH mode (6TiSCH) to deal with existing challenges and improve network performance to meet key requirements of industrial applications. The 6Top layer integrates TSCH (Time Slotted Channel Hopping)-MAC over IEEE 802.15.4 with the rest of the IPv6 stack where the schedule allocation is performed by scheduling function (SF). However, network scalability remains an open challenge. Specifically, the 6TiSCH Working Group (WG) do not define rules towards optimal schedule allocation over Time Slotted Channel Hopping (TSCH) mode of IEEE 802.15.4. In this paper, we propose Decentralized, and Broadcast-based Scalable Scheduling Reservation Protocol for 6TiSCH Networks (DeSSR). The experimental performance analysis demonstrates strong performance under steady and bursty traffic when compared with current SFs. This makes DeSSR a strong proposal contributing towards improving scalability in large-scale 6TiSCH networks.2023-12-03T00:00:00ZA modeling study of the impact of treatment policies on the evolution of resistance in sea lice on salmon farms
http://hdl.handle.net/1893/35646
Title: A modeling study of the impact of treatment policies on the evolution of resistance in sea lice on salmon farms
Author(s): Trombetta, Enrico; Jakubiak, Sara; Kutkova, Sara; Lipschutz, Debby; O'hare, Anthony; Enright, Jessica A
Abstract: Salmonid aquaculture is an important source of nutritious food with more than 2 million tonnes of fish produced each year. In most salmon producing countries, sea lice represent a major barrier to the sustainability of salmonid aquaculture. This issue is exacerbated by widespread resistance to chemical treatments on both sides of the Atlantic. Regulation for sea lice management mostly involves reporting lice counts and treatment thresholds, which depending on interpretation may encourage preemptive treatments. We have developed a stochastic simulation model of sea lice infestation including the lice life-cycle, genetic resistance to treatment, a wildlife reservoir, salmon growth and stocking practices in the context of infestation, and coordination of treatment between farms. Farms report infestation levels to a central organisation, and may then cooperate or not when coordinated treatment is triggered. Treatment practice then impacts the level of resistance in the surrounding sea lice population. Our simulation finds that treatment drives selection for resistance and coordination between managers is key. We also find that position in the hydrologically-derived network of farms can impact individual farm infestation levels and the topology of this network can impact overall infestation and resistance. We show how coordination and triggering of treatment alongside varying hydrological topology of farm connections affects the evolution of lice resistance, and thus optimise salmon quality within socioeconomic and environmental constraints. Network topology drives infestation levels in cages, treatments, and hence treatment-driven resistance. Thus farmer behaviour may be highly dependent on hydrologically position and local level of infestation.2023-11-29T00:00:00Z