Factors associated with variation in hospital use at the end of life in England

Objective: To identify the relative importance of factors influencing hospital use at the end of life. Design: Retrospective cohort study of person and health system effects on hospital use in the past 12 months modelling differences in admissions, bed days and whether a person died in hospital. Setting: Residents in England for the period 2009/2010 to 2011/2012 using Hospital Episodes Statistics (HES) data from all acute care hospitals in England funded by the National Health Service (NHS). Participants: 1 223 859 people registered with a GP in England who died (decedents) in England (April 2009–March 2012) with a record of NHS hospital care. Main outcome measures: Hospital admissions, and hospital bed days and place of death (in or out of hospital) in the past 12 months of life. Results: The mean number of admissions in the past 12 months of life averaged 2.28 occupying 30.05 bed days—excluding 9.8% of patients with no hospital history. A total of 50.8% of people died in hospital. Difference in hospital use was associated with a range of patient descriptors (age, gender and ethnicity). The variables with the greatest ‘explanatory power’ were those that described the diagnoses and causes of death. So, for example, 65% of the variability in the model of hospital admissions was explained by diagnoses. Only moderate levels of variation were explained by the hospital provider variables for admissions and deaths in hospital, though the impacts on total bed days was large. Conclusions: Comparative analyses of hospital utilisation should standardise for a range of patient specific variables. Though the models indicated some degree of variability associated with individual providers, the scale of this was not great for admissions and death in hospital but the variability associated with length of stay differences suggests that attempts to optimise hospital use should look at differences in lengths of stay and bed use. This study adds important new information about variability in admissions by diagnostic group, and variability in bed days by diagnostic group and eventual cause of death

Comparing primary and secondary health-care use between diagnostic routes before a colorectal cancer diagnosis: Cohort study using linked data

BACKGROUND: Survival in cancer patients diagnosed following emergency presentations is poorer than those diagnosed through other routes. To identify points for intervention to improve survival, a better understanding of patients' primary and secondary health-care use before diagnosis is needed. Our aim was to compare colorectal cancer patients' health-care use by diagnostic route. METHODS: Cohort study of colorectal cancers using linked primary and secondary care and cancer registry data (2009-2011) from four London boroughs. The prevalence of all and relevant GP consultations and rates of primary and secondary care use up to 21 months before diagnosis were compared across diagnostic routes (emergency, GP-referred and consultant/other). RESULTS: The data set comprised 943 colorectal cancers with 24% diagnosed through emergency routes. Most (84%) emergency patients saw their GP 6 months before diagnosis but their symptom profile was distinct; fewer had symptoms meeting urgent referral criteria than GP-referred patients. Compared with GP-referred, emergency patients used primary care less (IRR: 0.85 (95% CI 0.78-0.93)) and urgent care more frequently (IRR: 1.56 (95% CI 1.12; 2.17)). CONCLUSIONS: Distinct patterns of health-care use in patients diagnosed through emergency routes were identified in this cohort. Such analyses using linked data can inform strategies for improving early diagnosis of colorectal cancer

Engineering a static verification tool for GPU kernels

We report on practical experiences over the last 2.5 years related to the engineering of GPUVerify, a static verification tool for OpenCL and CUDA GPU kernels, plotting the progress of GPUVerify from a prototype to a fully functional and relatively efficient analysis tool. Our hope is that this experience report will serve the verification community by helping to inform future tooling efforts. © 2014 Springer International Publishing

A Solution to Weed Control in Grassland Containing White Clover

Productive grass with white clover can lead to advantages both in forage quantity and quality, economics and in meeting wider expectations detailed in recent EU and UK policy. The ability to achieve this agronomic success is currently difficult due to a lack of options for broad spectrum weed control that also allow establishment or preservation of a white clover population. The aim of this paper is to demonstrate that 3730XL, developed by Corteva Agriscience, is a solution to this critical success factor. Data is presented from 16 efficacy trials (10 from established grassland and 5 from newly sown) where white clover cover of plots treated with 3730XL was recorded relative to an untreated plot. Data is also presented from 106 weed control trials, against a selection of species, demonstrating the efficacy of 3730XL split by grassland scenario. The evidence presented highlights the capability of 3730XL to both control a broad spectrum of weed species and allow the establishment or preservation of white clover. Consequently, growers are able to cultivate the associated benefits that this confers

Coordination when there are restricted and unrestricted options

One might expect that, in pure coordination games, coordination would become less frequent as the number of options increases. Contrary to this expectation, we report an experiment which found more frequent coordination when the option set was unrestricted than when it was restricted. To try to explain this result, we develop a method for eliciting the general rules that subjects use to identify salient options in restricted and unrestricted sets. We find that each such rule, if used by all subjects, would generate greater coordination in restricted sets. However, subjects tend to apply different rules to restricted and unrestricted sets

A millennium-length reconstruction of Bear River stream flow, Utah

The Bear River contributes more water to the eastern Great Basin than any other river system. It is also the most significant source of water for the burgeoning Wasatch Front metropolitan area in northern Utah. Despite its importance for water resources for the region’s agricultural, urban, and wildlife needs, our understanding of the variability of Bear River’s stream flow derives entirely from the short instrumental record (1943–2010). Here we present a 1200-year calibrated and verified tree-ring reconstruction of stream flow for the Bear River that explains 67% of the variance of the instrumental record over the period from 1943 to 2010. Furthermore, we developed this reconstruction from a species that is not typically used for dendroclimatology, Utah juniper (Juniperus osteosperma). We identify highly significant periodicity in our reconstruction at quasi-decadal (7–8 year), multi-decadal (30 year), and centennial (>50 years) scales. The latter half of the 20th century was found to be the 2nd wettest (∼40-year) period of the past 1200 years, while the first half of the 20th century marked the 4th driest period. The most severe period of reduced stream flow occurred during the Medieval Warm Period (ca. mid-1200s CE) and persisted for ∼70 years. Upper-level circulation anomalies suggest that atmospheric teleconnections originating in the western tropical Pacific are responsible for the delivery of precipitation to the Bear River watershed during the October–December (OND) season of the previous year. The Bear River flow was compared to recent reconstructions of the other tributaries to the Great Salt Lake (GSL) and the GSL level. Implications for water management could be drawn from the observation that the latter half of the 20th century was the 2nd wettest in 1200 years, and that management for future water supply should take into account the stream flow variability over the past millennium

An approximate empirical Bayesian method for large-scale linear-Gaussian inverse problems

We study Bayesian inference methods for solving linear inverse problems, focusing on hierarchical formulations where the prior or the likelihood function depend on unspecified hyperparameters. In practice, these hyperparameters are often determined via an empirical Bayesian method that maximizes the marginal likelihood function, i.e., the probability density of the data conditional on the hyperparameters. Evaluating the marginal likelihood, however, is computationally challenging for large-scale problems. In this work, we present a method to approximately evaluate marginal likelihood functions, based on a low-rank approximation of the update from the prior covariance to the posterior covariance. We show that this approximation is optimal in a minimax sense. Moreover, we provide an efficient algorithm to implement the proposed method, based on a combination of the randomized SVD and a spectral approximation method to compute square roots of the prior covariance matrix. Several numerical examples demonstrate good performance of the proposed method

Exposing errors related to weak memory in GPU applications

© 2016 ACM.We present the systematic design of a testing environment that uses stressing and fuzzing to reveal errors in GPU applications that arise due to weak memory effects. We evaluate our approach on seven GPUS spanning three NVIDIA architectures, across ten CUDA applications that use fine-grained concurrency. Our results show that applications that rarely or never exhibit errors related to weak memory when executed natively can readily exhibit these errors when executed in our testing environment. Our testing environment also provides a means to help identify the root causes of such errors, and automatically suggests how to insert fences that harden an application against weak memory bugs. To understand the cost of GPU fences, we benchmark applications with fences provided by the hardening strategy as well as a more conservative, sound fencing strategy

Classical Scattering for a driven inverted Gaussian potential in terms of the chaotic invariant set

We study the classical electron scattering from a driven inverted Gaussian potential, an open system, in terms of its chaotic invariant set. This chaotic invariant set is described by a ternary horseshoe construction on an appropriate Poincare surface of section. We find the development parameters that describe the hyperbolic component of the chaotic invariant set. In addition, we show that the hierarchical structure of the fractal set of singularities of the scattering functions is the same as the structure of the chaotic invariant set. Finally, we construct a symbolic encoding of the hierarchical structure of the set of singularities of the scattering functions and use concepts from the thermodynamical formalism to obtain one of the measures of chaos of the fractal set of singularities, the topological entropy.Comment: accepted in Phy. Rev.