33 research outputs found
Two simple systems with cold atoms: quantum chaos tests and nonequilibrium dynamics
This article is an attempt to provide a link between the quantum
nonequilibrium dynamics of cold gases and fifty years of progress in the
lowdimensional quantum chaos. We identify two atomic systems lying on the
interface: two interacting atoms in a harmonic multimode waveguide and an
interacting two-component Bose-Bose mixture in a double-well potential. In
particular, we study the level spacing distribution, the wavefunction
statistics, the eigenstate thermalization, and the ability to thermalize in a
relaxation process as such.Comment: 18 pages, 9 figure
The importance of Antarctic krill in biogeochemical cycles
Antarctic krill (Euphausia superba) are swarming, oceanic crustaceans, up to two inches long, and best known as prey for whales and penguins â but they have another important role. With their large size, high biomass and daily vertical migrations they transport and transform essential nutrients, stimulate primary productivity and influence the carbon sink. Antarctic krill are also fished by the Southern Oceanâs largest fishery. Yet how krill fishing impacts nutrient fertilisation and the carbon sink in the Southern Ocean is poorly understood. Our synthesis shows fishery management should consider the influential biogeochemical role of both adult and larval Antarctic krill
Remineralization of particulate organic carbon in an ocean oxygen minimum zone
This work was funded by a NERC standard grant NE/E01559X/1
Effect of anthropogenic warming on microbial respiration and particulate organic carbon export rates in the sub-Antarctic Southern Ocean
Exploring the ecology of the mesopelagic biological pump
The oceansâ biological pump (BP) exports large amounts of particulate organic carbon (POC) to the mesopelagic zone (base of the euphotic zone â 1000âŻm depth). The efficiency at which POC is transferred through the mesopelagic zone determines the size of the deep ocean carbon store. Few observational BP studies focus on the mesopelagic, often leading to the need to oversimplify the representation of processes within this depth horizon in numerical models. In this review, we identify and describe three interlinked biological processes that act to regulate and control the transfer efficiency of POC through the mesopelagic zone; (1) direct sinking of phytoplankton cells and aggregates, (2) zooplankton community structure and (3) the microbial loop and associated carbon pump. We reveal previously unidentified relationships between planktonic community structure and POC transfer efficiency for specific regions. We also compare mesopelagic POC remineralisation depth (a proxy for POC transfer efficiency) with the permanent thermocline in different regions. Our analysis shows that even when mesopelagic POC transfer efficiency is low, such a transfer efficiency does not necessarily mean low carbon sequestration if the permanent thermocline is shallow, and we define a carbon sequestration ratio (Cseq, the remineralisation depth divided by the permanent thermocline) to highlight this. Low latitude regions typically have a higher Cseq than temperate and polar regions, and thus could be more important in transferring carbon on long timescales than previously thought. POC transfer efficiency should be regularly discussed in the context of the physical water properties such as the permanent thermocline, to truly assess an oceanic regionâs ability to sequester carbon. Improved understanding of mesopelagic ecological processes and links to surface processes will better constrain ecosystem models and improve projections of the future global carbon cycle
Perceptions and experiences of using automated bolus advisors amongst people with type 1 diabetes: A longitudinal qualitative investigation
Aims
We explored people's reasons for, and experiences of, using bolus advisors to determine insulin doses; and, their likes/dislikes of this technology.
Subjects and methods
42 people with type 1 diabetes who had received instruction in use of bolus advisors during a structured education course were interviewed post-course and 6 months later. Data were analysed thematically.
Results
Participants who considered themselves to have poor mathematical skills highlighted a gratitude for, and heavy reliance on, advisors. Others liked and chose to use advisors because they saved time and effort calculating doses and/or had a data storage facility. Follow-up interviews highlighted that, by virtue of no longer calculating their doses, participants could become deskilled and increasingly dependent on advisors. Some forgot what their mealtime ratios were; others reported a misperception that, because they were pre-programmed during courses, these parameters never needed changing. Use of data storage facilities could hinder effective review of blood glucose data and some participants reported an adverse impact on glycaemic control.
Discussion
While participants liked and perceived benefits to using advisors, there may be unintended consequences to giving people access to this technology. To promote effective use, on-going input and education from trained health professionals may be necessary