Improving the seasonal prediction of Northern Australian rainfall onset to help with grazing management decisions

The development of the Australian Community Climate and Earth-System Simulator-Seasonal prediction system version 1 (ACCESS-S1) signifies a major step towards addressing predictive limitations in multi-week to seasonal forecasting throughout Australia. It is anticipated that moving to ACCESS-S1 will provide improved skill in rainfall prediction during the dry to wet season transition period across tropical northern Australia. This is an important time for northern Australian livestock producers in terms of the decisions they make around pasture and livestock management. This study quantifies the hindcast skill of ACCESS-S1 for the northern rainfall onset (NRO), defined as the date when 50 mm of precipitation has accumulated at a given location from the 1st of September, heralding the shift towards greener pastures. We evaluate the raw model hindcasts, and compare them to hindcasts corrected for mean biases and those calibrated against observations. It is found that the raw ACCESS-S1 hindcasts broadly replicate the observed median NRO over the period 1990–2012, despite a ten- dency for earlier than observed onsets. In terms of forecasting the interannual variability of the NRO, the ca- librated hindcasts show the greatest skill, with the largest improvements over a climatological forecast in their probabilistic forecasts of an earlier or later than usual onset, with a large portion of northern Australian showing more than 10% improvement. With real-time NRO forecasts now generated by ACCESS-S1, it is expected that the calibrated predictions will help northern Australian graziers make better informed decisions around livestock management prior to the wet season

Seamless Precipitation Prediction Skill in the Tropics and Extratropics from a Global Model

The skill with which a coupled ocean–atmosphere model is able to predict precipitation over a range of time scales (days to months) is analyzed. For a fair comparison across the seamless range of scales, the verification is performed using data averaged over time windows equal in length to the lead time. At a lead time of 1 day, skill is greatest in the extratropics around 40°–60° latitude and lowest around 20°, and has a secondary local maximum close to the equator. The extratropical skill at this short range is highest in the winter hemisphere, presumably due to the higher predictability of winter baroclinic systems. The local equatorial maximum comes mostly from the Pacific Ocean, and thus appears to be mostly from El Niño–Southern Oscillation (ENSO). As both the lead time and averaging window are simultaneously increased, the extratropical skill drops rapidly with lead time, while the equatorial maximum remains approximately constant, causing the equatorial skill to exceed the extratropical at leads of greater than 4 days in austral summer and 1 week in boreal summer. At leads longer than 2 weeks, the extratropical skill flattens out or increases, but remains below the equatorial values. Comparisons with persistence confirm that the model beats persistence for most leads and latitudes, including for the equatorial Pacific where persistence is high. The results are consistent with the view that extratropical predictability is mostly derived from synoptic-scale atmospheric dynamics, while tropical predictability is primarily derived from the response of moist convection to slowly varying forcing such as from ENSO

Discrete Effects in Stellar Feedback: Individual Supernovae, Hypernovae, and IMF Sampling in Dwarf Galaxies

Using high-resolution simulations from the FIRE-2 (Feedback In Realistic Environments) project, we study the effects of discreteness in stellar feedback processes on the evolution of galaxies and the properties of the interstellar medium (ISM). We specifically consider the discretization of supernovae (SNe), including hypernovae (HNe), and sampling the initial mass function (IMF). We study these processes in cosmological simulations of dwarf galaxies with $z=0$ stellar masses $M_{\ast}\sim 10^{4}-3\times10^{6}\,M_\odot$ (halo masses $\sim 10^{9}-10^{10}\,M_\odot$). We show that the discrete nature of individual SNe (as opposed to a model in which their energy/momentum deposition is continuous over time, similar to stellar winds) is crucial in generating a reasonable ISM structure and galactic winds and in regulating dwarf stellar masses. However, once SNe are discretized, accounting for the effects of IMF sampling on continuous mechanisms such as radiative feedback and stellar mass-loss (as opposed to adopting IMF-averaged rates) has weak effects on galaxy-scale properties. We also consider the effects of rare HNe events with energies $\sim 10^{53}\,{\rm erg}$. The effects of HNe are similar to the effects of clustered explosions of SNe -- which are already captured in our default simulation setup -- and do not quench star formation (provided that the HNe do not dominate the total SNe energy budget), which suggests that HNe yield products should be observable in ultra-faint dwarfs today.Comment: 9 pages, 4 figure

Are Small Reimbursement Changes Enough to Change Cancer Care? Reimbursement Variation in Prostate Cancer Treatment

The Centers for Medicare and Medicaid Services recently initiated small reimbursement adjustments to improve the value of care delivered under fee-for-service. To estimate the degree to which reimbursement influences physician decision making, we examined utilization of gonadotropin-releasing hormone (GnRH) agonists among urologists as Part B drug reimbursement varied in a fee-for-service environment

Multi‑week prediction of livestock chill conditions associated with the northwest Queensland floods of February 2019

The compound extreme weather event that impacted northern Queensland in February 2019 featured record-breaking rainfall, persistent high wind gusts and relatively cold day-time temperatures. This caused livestock losses numbering around 500,000 in the northwest Queensland Gulf region. In this study, we examine the livestock chill conditions associated with this week-long compound weather event and its potential for prediction from eleven world-leading sub-seasonal to seasonal (S2S) forecast systems. The livestock chill index combines daily rainfall, wind and surface temperature data. Averaged over the event week, the potential heat loss of livestock was in the moderate to high category, with severe conditions on the day of peak rainfall (5 February). Using calibrated forecasts from the Bureau of Meteorology's S2S forecast system, ACCESS-S1, a 1-week lead prediction showed a 20–30% probability of extreme livestock chill conditions over the northwest Queensland Gulf region, however the highest probabilities were located to the west of where the greatest livestock impacts were observed. Of the remaining ten S2S systems, around half predicted a more than 20% chance of extreme conditions, more than twice the climatological probability. It appears that the prediction accuracy arose from the skilful forecasts of extreme rainfall, as opposed to cold day-time temperature and strong wind forecasts. Despite a clear association between the observed extreme weather conditions and an active Madden–Julian Oscillation (MJO) event stalling in the western Pacific, the majority of 1-week lead S2S forecasts showed little indication of a slow-down in the MJO. As the livestock chill index was developed for southern Australian sheep, it may not be the best metric to represent the effects of exposure on tropical cattle breeds. Hence, this study draws attention to the need for tailored diagnostics that better represent the cold effects of summer tropical cyclones and tropical depressions on northern Australian livestock

Healthcare resource utilisation and related costs of patients with CKD from the UK: a report from the DISCOVER CKD retrospective cohort

Background Chronic kidney disease (CKD) is widely reported to decrease quality of life, increase morbidity and mortality and cause increased healthcare resource utilisation (HCRU) as the disease progresses. However, there is a relative paucity of accurate and recent estimates of HCRU in this patient population. Our aim was to address this evidence gap by reporting HCRU and related costs in patients with CKD from the UK primary and secondary care settings. Methods HCRU and cost estimates of CKD were derived for UK patients included in the DISCOVER CKD cohort study using clinical records from the Clinical Practice Research Datalink linked to external databases. Patients with a history of transplant or undergoing dialysis were not included. HCRU and costs were stratified by CKD severity using the urinary albumin:creatinine ratio (UACR) and estimated glomerular filtration rate. Results Hospitalisation rates more than tripled between low (A1) and high (A3) UACR categories and the mean annual per-patient costs ranged from £4966 (A1) to £9196 (A3) and from £4997 (G2) to £7595 (G5), demonstrating that a large healthcare burden can be attributed to a relatively small number of patients with later stage CKD, including those with kidney failure and/or albuminuria. Conclusions HCRU and costs associated with CKD impose a substantial burden on the healthcare system, particularly in the more advanced stages of CKD. New interventions that can delay the progression of CKD to kidney failure may not only prolong the patient’s life, but would also provide significant resource and cost savings to healthcare providers

Crossover Scaling in Dendritic Evolution at Low Undercooling

We examine scaling in two-dimensional simulations of dendritic growth at low undercooling, as well as in three-dimensional pivalic acid dendrites grown on NASA's USMP-4 Isothermal Dendritic Growth Experiment. We report new results on self-similar evolution in both the experiments and simulations. We find that the time dependent scaling of our low undercooling simulations displays a cross-over scaling from a regime different than that characterizing Laplacian growth to steady-state growth

The Structure of Episodic Memory: Ganeri's ‘Mental Time Travel and Attention’

We offer a framework for assessing what the structure of episodic memory might be, if one accepts the Buddhist denial of persisting selves. This paper is a response to Jonardon Ganeri's paper "Mental time travel and attention", which explores Buddhaghosa's ideas about memory. (It will eventually be published with a reply by Ganeri)