Reproducible aspects of the climate of space weather over the last five solar cycles

Each solar maximum interval has a different duration and peak activity level which is reflected in the behaviour of key physical variables that characterize solar and solar wind driving and magnetospheric response. The variation in the statistical distributions of the F10.7 index of solar coronal radio emissions, the dynamic pressure PDyn and effective convection electric field Ey in the solar wind observed in situ upstream of Earth, the ring current index DST, and the high latitude auroral activity index AE, are tracked across the last five solar maxima. For each physical variable we find that the distribution tail (the exceedences above a threshold) can be rescaled onto a single master distribution using the mean and variance specific to each solar maximum interval. We provide Generalized Pareto Distribution fits to the different master distributions for each of the variables. If the mean and variance of the large‐to extreme observations can be predicted for a given solar maximum then their full distribution is known

The dependence of solar wind burst size on burst duration and its invariance across solar cycles 23 and 24

Time series of solar wind variables are “bursty” in nature. Bursts, or excursions, in the time series of solar wind parameters are associated with various transient structures in the solar wind plasma, and are often the drivers of increased space weather activity in Earth's magnetosphere. We define bursts by setting a threshold value of the time series and identifying how often, and for how long, it is exceeded. This allows us to study how the statistical distributions and scaling properties of burst parameters vary over solar cycles 23 and 24. We find the distributions of burst duration and integrated burst size vary over the solar cycle, and between the equivalent phases of consecutive cycles. However, there exists a single power law scaling relation between burst size and duration, with a joint area‐duration scaling exponent α that is independent of the solar cycle. This provides a solar cycle invariant constraint between possible sizes and durations of solar wind bursts that can occur

Global strategic partnerships to share international and local expertise between private sector and NGOs

The term ‘partnership’ can cover a wide range of relationships between different types of organisations. However, genuine partnerships between the private and NGO sectors are still relatively uncommon. The global consultancy firm Arup has developed a number of partnerships with NGOs in the water sector to bring international expertise to help solve local problems. This paper briefly reviews the partnership context and describes two water projects – one in Bangladesh and one in Ghana - where Arup staff have worked with local NGOs to develop locally appropriate solutions to technical problems. The paper explores the mutual benefits that both organisations can enjoy from this type of partnership

How robust are recommended waiting times to pacing after cardiac surgery that are derived from observational data?

AIMS: For bradycardic patients after cardiac surgery, it is unknown how long to wait before implanting a permanent pacemaker (PPM). Current recommendations vary and are based on observational studies. This study aims to examine why this variation may exist. METHODS AND RESULTS: We conducted first a study of patients in our institution and second a systematic review of studies examining conduction disturbance and pacing after cardiac surgery. Of 5849 operations over a 6-year period, 103 (1.8%) patients required PPM implantation. Only pacing dependence at implant and time from surgery to implant were associated with 30-day pacing dependence. The only predictor of regression of pacing dependence was time from surgery to implant. We then applied the conventional procedure of receiver operating characteristic (ROC) analysis, seeking an optimal time point for decision-making. This suggested the optimal waiting time was 12.5 days for predicting pacing dependence at 30 days for all patients (area under the ROC curve (AUC) 0.620, P = 0.031) and for predicting regression of pacing dependence in patients who were pacing-dependent at implant (AUC 0.769, P < 0.001). However, our systematic review showed that recommended optimal decision-making time points were strongly correlated with the average implant time point of those individual studies (R = 0.96, P < 0.001). We further conducted modelling which revealed that in any such study, the ROC method is strongly biased to indicate a value near to the median time to implant as optimal. CONCLUSION: When commonly used automated statistical methods are applied to observational data with the aim of defining the optimal time to pacing after cardiac surgery, the suggested answer is likely to be similar to the average time to pacing in that cohort

Improving the Energy Performance Contracting Process using Building Performance Simulation: Lessons Learnt from Post Occupancy Investigation of a Case Study in the UK

There is a niche trend to use ‘Energy Performance Contracts’ (EPCs), for new buildings to ensure that minimum energy performance is achieved in practice. Building Performance Simulation (BPS) help to estimate performance and assess risks during design, construction and operational stages. This paper reports on an office building in the UK that has been procured under an EPC. The current performance shows that it will be challenging for the building to achieve the target. Being one of the first new buildings in the UK to be subjected to an EPC, analysis of the design, construction and operation process, provides insights into the specific issues related to building procurement and operation. It is suggested that scenario analysis, accounting for uncertainties and dynamic BPS should be used throughout the procurement process to quantify and manage the risks associated with performance targets. The paper also identifies that if performance targets are not defined comprehensively, there can be unintended consequences that lead to underperformance

Observations of red-giant variable stars by Aboriginal Australians

Aboriginal Australians carefully observe the properties and positions of stars, including both overt and subtle changes in their brightness, for subsistence and social application. These observations are encoded in oral tradition. I examine two Aboriginal oral traditions from South Australia that describe the periodic changing brightness in three pulsating, red-giant variable stars: Betelgeuse (Alpha Orionis), Aldebaran (Alpha Tauri), and Antares (Alpha Scorpii). The Australian Aboriginal accounts stand as the only known descriptions of pulsating variable stars in any Indigenous oral tradition in the world. Researchers examining these oral traditions over the last century, including anthropologists and astronomers, missed the description of these stars as being variable in nature as the ethnographic record contained several misidentifications of stars and celestial objects. Arguably, ethnographers working on Indigenous Knowledge Systems should have academic training in both the natural and social sciences.Comment: The Australian Journal of Anthropology (2018

Development of a rapid semi-automated tool to measure total kidney volume in autosomal dominant polycystic kidney disease

Background Total kidney volume (TKV) is an approved early prognostic marker of progression in autosomal dominant polycystic kidney disease. The approval of tolvaptan for patients with rapid disease progression in Europe requires accurate patient stratification. Current methods of TKV measurement rely on manual segmentation which is time consuming, restricting its clinical use. To address this important clinical challenge we report the development and performance of a semi-automated method (Sheffield TKV tool) to measure TKV in patients with this disease. Methods 1.5T MRI scans were acquired (Siemens Avanto) in 61 adult patients with autosomal dominant polycystic kidney disease. Manual segmentation of the kidneys was performed on T2 true fast imaging with steady state precession MRI. Computational semi-automated segmentation methods were tested in a subgroup of ten patients and the optimum method used in all 61 cases to measure TKV (mL). Manual and semi-automated results were compared by Bland–Altman analyses. Processing time for manual and semi-automated methods were recorded. Findings Our cohort consisted of 29 men and 32 women (mean age 45 years, SD 14). Estimated GFR (eGFR) in patients within 1 month of the MRI ranged between 32 and 138 mL/min. TKV measured by manual segmentation ranged between 258 and 3680 mL. The Sheffield TKV tool performed optimally for calculating TKV, reporting accurate results in 80% of cases compared with manual TKV. Inaccuracies were associated with erroneous inclusion of blood vessels, the renal hilum, or leakage into neighbouring tissues, and overall were more frequent in smaller kidneys. Processing time for TKV with the Sheffield TKV tool was 2–5 min compared with 20–30 min for manual segmentation. Interpretation We describe a new rapid, semi-automated method for measuring TKV on MRI which should be a useful tool for evaluating patients with autosomal dominant polycystic kidney disease. We plan to optimise MRI acquisition sequences and extract the renal hilar volume to improve performance of the Sheffield TKV tool and validate it in another population with autosomal dominant polycystic kidney disease, with the ultimate aim of using it in clinical practice. Funding Insigneo (Institute for in silico medicine) bursary (from Sheffield Teaching Hospitals NHS Foundation Trust), National Institute for Health Research

The development of a space climatology: 3. Models of the evolution of distributions of space weather variables with timescale

We study how the probability distribution functions of power input to the magnetosphere Pα and of the geomagnetic ap and Dst indices vary with averaging timescale, , between 3 hours and 1 year. From this we develop and present algorithms to empirically model the distributions for a given and a given annual mean value. We show that lognormal distributions work well for ap, but because of the spread of Dst for low activity conditions, the optimum formulation for Dst leads to distributions better described by something like the Weibull formulation. Annual means can be estimated using telescope observations of sunspots and modelling, and so this allows the distributions to be estimated at any given between 3 hour and 1 year for any of the past 400 years, which is another important step towards a useful space weather climatology. The algorithms apply to the core of the distributions and can be used to predict the occurrence rate of “large” events (in the top 5% of activity levels): they may contain some, albeit limited, information relevant to characterizing the much rarer “superstorm” events with extreme value statistics. The algorithm for the Dst index is the more complex one because, unlike ap, Dst can take on either sign and future improvements to it are suggested