Special symplectic Lie groups and hypersymplectic Lie groups

A special symplectic Lie group is a triple $(G,\omega,\nabla)$ such that $G$ is a finite-dimensional real Lie group and $\omega$ is a left invariant symplectic form on $G$ which is parallel with respect to a left invariant affine structure $\nabla$. In this paper starting from a special symplectic Lie group we show how to ``deform" the standard Lie group structure on the (co)tangent bundle through the left invariant affine structure $\nabla$ such that the resulting Lie group admits families of left invariant hypersymplectic structures and thus becomes a hypersymplectic Lie group. We consider the affine cotangent extension problem and then introduce notions of post-affine structure and post-left-symmetric algebra which is the underlying algebraic structure of a special symplectic Lie algebra. Furthermore, we give a kind of double extensions of special symplectic Lie groups in terms of post-left-symmetric algebras.Comment: 32 page

Evaluating cost benefits from a heat health warning system in Adelaide, South Australia

OnlinePublObjective: To examine the cost benefits of a heat health warning system (HHWS) in South Australia. Methods: Information from key agencies was used to estimate the costs associated with the South Australian HHWS, including for three targeted public health interventions. Health cost savings were estimated based on previously reported HHWS-attributable reductions in hospital and emergency department (ED) admissions and ambulance callouts. Results: The estimated cost for a one-week activation of the HHWS was AU$593,000. Activation costs compare favourably with the potential costs averted through HHWS-attributable reductions in hospital admissions and ambulance callouts with an estimated benefit-cost ratio of 2.0–3.3.Conclusions: On the basis of estimated cost benefit, the South Australian HHWS is a no-regret public health response to heatwaves. Implications for public health: As global temperatures rise there are likely to be significant health impacts from more frequent and intense heatwaves. This study indicates that HHWSs incorporating targeted supports for vulnerable groups are likely to be cost-effective public health interventions.Susan Williams, Monika Nitschke, Berhanu Yazew Wondmagegn, Michael Tong, Jianjun Xiang, Alana Hansen, John Nairn, Jonathan Karnon, Peng B

Emergency department visits and associated healthcare costs attributable to increasing temperature in the context of climate change in Perth, Western Australia, 2012-2019

Increasing temperature and its impact on population health is an emerging significant public health issue in the context of climate change in Australia. While previous studies have primarily focused on risk assessment, very few studies have evaluated heat-attributable emergency department (ED) visits and associated healthcare costs, or projected future health and economic burdens. This study used a distributed lag non-linear model to estimate heat attributable ED visits and associated healthcare costs from 13 hospitals in Perth, Western Australia, and to project the future healthcare costs in 2030s and 2050s under three climate change scenarios—Representative Concentration Pathways (RCPs)2.6, RCP4.5 and RCP8.5. There were 3697 ED visits attributable to heat (temperatures above 20.5 °C) over the study period 2012–2019, accounting for 4.6% of the total ED visits. This resulted in AU$2.9 million in heat-attributable healthcare costs. The number of ED visits projected to occur in the 2030s and 2050s ranges from 5707 to 9421 under different climate change scenarios, which would equate to AU$ 4.6–7.6 million in heat associated healthcare costs. The heat attributable fraction for ED visits and associated healthcare costs would increase from 4.6% and 4.1% in 2010s to 5.0%–6.3% and 4.4%–5.6% in 2030s and 2050s, respectively. Future heat attributable ED visits and associated costs will increase in Perth due to climate change. Excess heat will generate a substantial population health challenge and economic burdens on the healthcare system if there is insufficient heat adaptation. It is vital to reduce greenhouse gas emissions, develop heat-related health interventions and optimize healthcare resources to mitigate the negative impact on the healthcare system and population health in the face of climate change.Michael Xiaoliang Tong, Berhanu Yazew Wondmagegn, Jianjun Xiang, Susan Williams, Alana Hansen, Keith Dear ... et al

Hospital healthcare costs attributable to heat and future estimations in the context of climate change in Perth, Western Australia

Climate change with increasing temperature is making a significant impact on human health, including more heat-related diseases, and increasing the burden on the healthcare system. Although many studies have explored the association between increasing temperatures and negative health outcomes, research on the associated costs of heat-related diseases remains relatively sparse. Furthermore, estimations of future costs associated with heat-attributable hospital healthcare have not been well explored. This study used a distributed lag nonlinear model to estimate heat-attributable hospital healthcare costs in Perth, Western Australia. Using 2006–2012 as the baseline, future costings for 2026–2032 and 2046–2052 were estimated under RCP2.6, RCP4.5, and RCP8.5. Higher temperatures were found to be associated with increased hospital healthcare costs. The total hospital costs attributable to heat over the baseline period 2006–2012 was estimated to be 79.5 million AUD, with costs for mental health hospitalizations being the largest contributor of the heat-related conditions examined. Costs are estimated to increase substantially to 125.8–129.1 million AUD in 2026–2032, and 174.1–190.3 million AUD by midcentury under climate change scenarios. Our findings of a notable burden of heat-attributable healthcare costs now and in the future emphasize the importance of climate change adaptation measures to reduce the adverse health effects of increasing temperatures and heat exposure on the people of Perth.Michael Xiaoliang Tong, Berhanu Yazew Wondmageg, Susan William, Alana Hanse, Keith Dear, Dino Pisaniello … et al

Understanding current and projected emergency department presentations and associated healthcare costs in a changing thermal climate in Adelaide, South Australia

Published online 4 April 2022Background: Exposure to extreme temperatures is associated with increased emergency department (ED) presentations. The resulting burden on health service costs and the potential impact of climate change is largely unknown. This study examines the temperature-EDs/ cost relationships in Adelaide, South Australia and how this may be impacted by increasing temperatures. Methods: A time series analysis using a distributed lag nonlinear model was used to explore the exposure– response relationships. The net-attributable, cold-attributable and heat-attributable ED presentations for temperature-related diseases and costs were calculated for the baseline (2014–2017) and future periods (2034–2037 and 2054–2057) under three climate representative concentration pathways (RCPs). Results: The baseline heat-attributable ED presentations were estimated to be 3600 (95% empirical CI (eCI) 700 to 6500) with associated cost of $A4.7 million (95% eCI 1.8 to 7.5). Heat-attributable ED presentations and costs were projected to increase during 2030s and 2050s with no change in the cold-attributable burden. Under RCP8.5 and population growth, the increase in heat-attributable burden would be 1.9% (95% eCI 0.8% to 3.0%) for ED presentations and 2.5% (95% eCI 1.3% to 3.7%) for ED costs during 2030s. Under the same conditions, the heat effect is expected to increase by 3.7% (95% eCI 1.7% to 5.6%) for ED presentations and 5.0% (95% eCI 2.6% to 7.1%) for ED costs during 2050s. Conclusions: Projected climate change is likely to increase heat-attributable emergency presentations and the associated costs in Adelaide. Planning health service resources to meet these changes will be necessary as part of broader risk mitigation strategies and public health adaptation actions.Berhanu Yazew Wondmagegn, Jianjun Xiang, Keith Dear, Susan Williams, Alana Hansen, Dino Pisaniello, Monika Nitschke, John Nairn, Ben Scalley, Alex Xiao, Le Jian, Michael Tong, Hilary Bambrick, Jonathan Karnon, Peng B

Heat-attributable hospitalisation costs in Sydney: Current estimations and future projections in the context of climate change

The association between heat and diseases has been extensively reported. However, its associated healthcare costs and attributable fraction due to heat were scarcely explored. The aim of this study was to estimate hospitalisation costs attributable to heat in Sydney, and to project future costs under climate change scenarios. Using a distributed lag nonlinear model, this study estimated heat-attributable hospitalisation costs in Sydney; and using 2010–2016 data as baseline, future costs for 2030s and 2050s were estimated under three climate change scenarios depending on greenhouse gas emissions - Representative Concentration Pathway (RCP)2.6, RCP4.5, and RCP8.5. Higher temperatures were found to be associated with increased hospitalisation costs. About 8–9% of the total hospitalisation costs were attributable to heat. The total costs attributable to heat over the baseline period 2010–2016 were estimated to be AU$252 million, with mental health hospitalisation making the largest contribution. Hospitalisation costs are estimated to increase substantially to AU$387–399 million in the 2030s, and AU$506–570 million by mid-century under different climate change scenarios. Urgent action is required to reduce heat-attributable illness in our communities, particularly for mental health conditions. Relevant preparations including healthcare workforce capacity building and resource allocation are needed to deal with these challenges in the context of climate change.Michael Tong, Berhanu Yazew Wondmagegn, Jianjun Xiang, Susan Williams, Alana Hansen, Keith Dear, Dino Pisaniello, Blesson Mathew Varghese, Jianguo Xiao, Le Jian, Ben Scalley, Monika Nitschke, John Nairn, Hilary Bambrick, Jonathan Karnon, Peng B