Gaia DR2 Distances and Peculiar Velocities for Galactic Black Hole Transients

We report on a first census of Galactic black hole X-ray binary (BHXRB) properties with the second data release (DR2) of {\em Gaia}, focusing on dynamically confirmed and strong candidate black hole transients. DR2 provides five-parameter astrometric solutions including position, parallax and proper motion for 11 of a sample of 24 systems. Distance estimates are tested with parallax inversion as well as Bayesian inference. We derive an empirically motivated characteristic scale length of $L$=2.17$\pm$0.12 kpc for this BHXRB population to infer distances based upon an exponentially decreasing space density prior. Geometric DR2 parallaxes provide new, independent distance estimates, but the faintness of this population in quiescence results in relatively large fractional distance uncertainties. Despite this, DR2 estimates generally agree with literature distances. The most discrepant case is BW Cir, for which detailed studies of the donor star have suggested a distant location at >~25 kpc. A large DR2 measured parallax and relatively high proper motion instead prefer significantly smaller distances, suggesting that the source may instead be amongst the nearest of XRBs. However, both distances create problems for interpretation of the source, and follow-up data are required to resolve its true nature. DR2 also provides a first distance estimate to one source, MAXI J1820+070, and novel proper motion estimates for 7 sources. Peculiar velocities relative to Galactic rotation exceed $\sim$ 50 km s$^{-1}$ for the bulk of the sample, with a median system kinetic energy of peculiar motion of $\sim$ 5 $\times$ 10$^{47}$ erg. BW Cir could be a new high-velocity BHXRB if its astrometry is confirmed. A putative anti-correlation between peculiar velocity and black hole mass is found, as expected in mass-dependent BH kick formation channels, but this trend remains weak in the DR2 data.Comment: MNRAS in pres

Fault-current limiter using a superconducting coil

A novel circuit, consisting of solid-state diodes and a biased superconducting coil, for limiting the fault currents in three-phase ac systems is presented. A modification of the basic circuit results in a solid-state ac breaker with current-limiting features. The operating characteristics of the fault-current limiter and the ac breaker are analyzed. An optimization procedure for sizing the superconducting coil is derived

The effect of carbohydrate dose and timing on timed effort and time to exhaustion within a simulated cycle race in male professional cyclists

A key performance limitation affecting professional endurance cycling is carbohydrate storage and utilisation (Pöchmüller, Schwingshack, Colombani & Hoffmann, 2016, Journal of the International Society of Sports Nutrition, 13). Muscle glycogen stores alone are inefficient at maintaining optimal blood glucose levels beyond two hours of exercise; consequently, exogenous CHO is commonly used to counteract this (Jeukendrup, 2011, Journal of Sports Sciences, 21, 91-99). High concentrations of CHO can cause drops in blood glucose, excessive glycogen utilisation and gastrointestinal discomfort (GID) (Jeukendrup, 2011). Therefore, the aim of this study was to determine if frequent, smaller CHO feedings would be preferable to large, bolus CHO feedings on time trial cycling performance. With institutional ethics approval, 5 professional cyclists completed a 4h simulated cycle ride with 3 timed efforts in a randomised, cross-over, double blind design study. Each timed effort occurred in the last 10 min of each hour (TE1, TE2, TE3); participants were asked to cycle with maximum effort for this time. There was also a final effort at the end of the 4th hour to replicate a sprint finish. This was measured as time to exhaustion (TTE). Two interventions were used; a frequent feed (F) where participants drank 20g maltodextrin in 300ml flavoured water solution 3 times per hour and a bolus feed (B) where participants drank 60g maltodextrin solution once per hour. Heart rate, power output, GID, perceived exertion (RPE), blood lactate and blood glucose were recorded before and after TE1, TE2, TE3 and TTE. Wilcoxen signed rank test and Cohen’s D was performed to study differences between interventions and effect sizes.In the F intervention, average watts were significantly higher at TE2 (P<0.05 d=0.75) and TE3 (P<0.05 d=1.21) and the RPE was lower TE1 (P≥0.05 d=1.12), TE2 (P<0.05, d=1.12) and TTE (P≥0.05 d=1.12) compared to B. There was no significant difference between any other variables. The results suggest that despite power output being higher, RPE was lower in the F intervention. Gut absorption of CHO is limited to 1g/h (Jeukendrup, 2011), which may help explain these findings. This is one of the first studies to look at concentration and timing of CHO consumption in endurance cycling. Regular feeds of 20g CHO may be more beneficial on power output and RPE in endurance cycling compared to hourly 60g feeds

MASCC recommendations on the management of constipation in patients with advanced cancer

PURPOSE: The Palliative Care Study Group of the Multinational Association for Supportive Care in Cancer formed a subgroup to develop evidence-based recommendations on the management of constipation in patients with advanced cancer. METHODS: These recommendations were developed in accordance with the MASCC Guidelines Policy. A search strategy for Medline was developed, and the Cochrane Database of Systematic Reviews and the Cochrane Central Register of Controlled Trials were explored for relevant reviews/trials respectively. The recommendations were categorised by the level of evidence and a "category of guideline" based on the level of evidence (i.e. "recommendation", "suggestion", or "no guideline possible"). RESULTS: The group produced 15 recommendations, with varying levels of evidence and so varying categories of guideline. The recommendations relate to the assessment, the treatment, and the re-assessment of constipation. CONCLUSIONS: These recommendations provide a framework for the management of constipation in advanced cancer, although every patient needs individualised management

CorrSim: a multiwavelength timing observation simulator

Studying the rapid variability of many astronomical objects is key to understanding the underlying processes at play. However, obtaining data well-suited to this task can be tricky, especially for simultaneous multiwavelength observations. Parameters often have to be fine-tuned while ‘on-site,’ or observations may only be found to not achieve their goals later. Here, we present CorrSim; a program tailored to X-ray Binary analysis, and expandable to many kinds of multiwavelength coordinated observations. CorrSim takes power spectra, coherence, and lags, and returns a simulated multiwavelength observation. The goals of this are: (i) To simulate a potential observation; (ii) To investigate how different Fourier models affect a system’s variability, including data products like cross-correlation functions); and (iii) To simulate existing data and investigate its trustworthiness. We outline CorrSim’s methodology, show how a variety of parameters (e.g. noise sources, observation length, telescope choice) can affect data, and present examples of the software in action. Through CorrSim, we also detail the effects of the length of the data train on Fourier and correlation function uncertainties. We also highlight previous CorrSim modelling, noting that the ‘pre-cognition dip’ seen in X-ray binaries can be constructed by periodic processes, and discuss this result in the wider context

Cross-sectional evaluation of a longitudinal consultation skills course at a new UK medical school

Background: Good communication is a crucial element of good clinical care, and it is important to provide appropriate consultation skills teaching in undergraduate medical training to ensure that doctors have the necessary skills to communicate effectively with patients and other key stakeholders. This article aims to provide research evidence of the acceptability of a longitudinal consultation skills strand in an undergraduate medical course, as assessed by a cross-sectional evaluation of students' perceptions of their teaching and learning experiences. Methods: A structured questionnaire was used to collect student views. The questionnaire comprised two parts: 16 closed questions to evaluate content and process of teaching and 5 open-ended questions. Questionnaires were completed at the end of each consultation skills session across all year groups during the 2006-7 academic year (5 sessions in Year 1, 3 in Year 2, 3 in Year 3, 10 in Year 4 and 10 in Year 5). 2519 questionnaires were returned in total. Results: Students rated Tutor Facilitation most favourably, followed by Teaching, then Practice & Feedback, with suitability of the Rooms being most poorly rated. All years listed the following as important aspects they had learnt during the session: • how to structure the consultation • importance of patient-centredness • aspects of professionalism (including recognising own limits, being prepared, generally acting professionally). All years also noted that the sessions had increased their confidence, particularly through practice. Conclusions: Our results suggest that a longitudinal and integrated approach to teaching consultation skills using a well structured model such as Calgary-Cambridge, facilitates and consolidates learning of desired process skills, increases student confidence, encourages integration of process and content, and reinforces appreciation of patient-centredness and professionalism

Rainfall-induced differential settlements of foundations on heterogeneous unsaturated soils

This study stochastically investigates the rainfall-induced differential settlement of a centrally loaded, rigid strip foundation on an unsaturated soil with spatially varying values of either preconsolidation stress or porosity. The differential settlement (between the two foundation ends) is calculated at various times during rainfall by way of a coupled, hydro-mechanical, finite-element analysis. The Barcelona basic model describes the mechanical behaviour of the soil, and the van Genuchten relationships describe water retention and permeability. The variability of soil properties is modelled by means of random fields with spatial correlation in the framework of a Monte Carlo simulation. The study demonstrates that the occurrence of rainfall-induced differential settlements can be consistently analysed using concepts of unsaturated soil mechanics and random field theory. Results show that differential settlements can be vastly underpredicted (or even completely missed) if random heterogeneity and partial saturation are not simultaneously considered. The variation of differential settlements and their statistics during the rainfall depend on the magnitude of the applied load and the statistics of soil variability. Moreover, the transient phase of infiltration and a spatial correlation length equal to the width of the foundation pose the highest risk of differential settlement

A mixed methods approach to advance the understanding of physical activity behaviour during pregnancy

An active pregnancy encompasses benefits that apply to both mother and baby. However, before investing resources in interventions aimed at changing or supporting expectant mothers’ physical activity behaviours, it is necessary to have a greater fundamental understanding of the modifiable factors influencing women’s decisions during this time. Therefore, the main purpose of this study was to investigate the socio-cognitive determinants of physical activity during pregnancy. A mixed methods research approach using a multiphase design framed by the Theory of Planned Behaviour (TPB; Ajzen, 1991, Organizational Behavior and Human Decision Processes, 50, 179-211) guided the investigation. Following ethical approval and permission to carry out the study, participants were recruited from randomly selected antenatal clinics in the East Kent region of England. Application of the TPB required both qualitative and quantitative cross-sectional data to be collected. Study One (n = 18) involved the elicitation of pregnant women’s beliefs towards being physically active. The modal salient behavioural, normative and control beliefs were used to inform the development of a TPB questionnaire which was implemented during the next phase of the investigation. Study Two (n = 78) examined the predictive utility of the TPB in explaining pregnant women’s physical activity intentions and behaviour and scrutinised the role of past behaviour within this context. Finally, Study Three (n = 10) comprised semi-structured interviews involving community midwives. Meta-inferences maintained the function of improving the validity of the study and advancing the overall aim of the research project. Specifically, triangulation was used to ascertain convergence, corroboration, and correspondence of findings between studies. Whilst results of the individual studies hold merit, meta-inferences point towards the development of three main themes: (1) pregnant women lack access to the necessary information that would allow them to make informed decisions regarding their engagement in physical activities; (2) a co-ordinated effort involving interprofessional collaboration is required to support pregnant women in overcoming barriers associated with regular physical activity participation; and (3) profiling pregnant women according to motivation and behaviour status could serve as a useful and manageable starting point for intervening to produce positive changes in pregnant women’s physical activity behaviour. In normalising physical activity during pregnancy and achieving better health outcomes for mothers and babies, it is necessary to consider the modifiable factors involved in behaviour change, identify opportune moments to intervene, and involve a network of professionals in facilitating and supporting pregnant women’s engagement with physical activities