Using imprecise continuous time Markov chains for assessing the reliability of power networks with common cause failure and non-immediate repair.

We explore how imprecise continuous time Markov chains can improve traditional reliability models based on precise continuous time Markov chains. Specifically, we analyse the reliability of power networks under very weak statistical assumptions, explicitly accounting for non-stationary failure and repair rates and the limited accuracy by which common cause failure rates can be estimated. Bounds on typical quantities of interest are derived, namely the expected time spent in system failure state, as well as the expected number of transitions to that state. A worked numerical example demonstrates the theoretical techniques described. Interestingly, the number of iterations required for convergence is observed to be much lower than current theoretical bounds

Psychological interventions used to reduce sports injuries: A systematic review of real-world effectiveness.

Objective: To systematically review studies examining the role of psychological interventions in injury prevention. The primary research question was: (1) What is the real-world effectiveness of psychological intervention in preventing sports injuries? Design: Mixed method systematic review with best evidence synthesis Data sources: CINAHL, MEDLINE, PsycARTICLES, PsycINFO, SPORTDiscus, Science Direct and PubMed Eligibility criteria for selecting studies: Randomised control trials (RCTs), non-RCTs that included a comparison group, before and after study designs and qualitative methods. Studies were required to outline specific unimodal or multimodal psychological interventions used in relation to injury prevention in the real-world setting. Outcome measure: Studies were independently appraised with the Mixed-Methods Appraisal Tool (MMAT). • Results: Thirteen papers (incorporating 14 studies) met the eligibility criteria, of which 93% (13/14) reported a decrease in injury rates (effect size range = 0.2 – 1.21). There was an overall moderate risk of bias in reporting (52%). There is a dominance of stress management-based interventions in literature due to the prominence of the Model of Stress and Athletic Injury within the area. Summary/conclusions: Psychological interventions demonstrate small (0.2) to large (1.21) effects on sports injury rates. The research area demonstrates a cumulative moderate risk in reporting bias (52%). PROSPERO registration: CRD4201603587

The Quaternary Bone Caves and Associated Sites at Wallingford, Jamaica

A group of caves associated with the sink of the One Eye River in St. Elizabeth Parish, Jamaica, have been the subject of numerous important palaeontological investigations beginning 1919. Unfortunately, considerable confusion has arisen in the literature through inadequate documentation of different sites. The caves of the immediate area are described and located, and their palaeontological significance is summarised in the light of recent taxonomic review and relevant geochronological evidence

One Sweetly Solemn Thought

https://digitalcommons.library.umaine.edu/mmb-ps/1867/thumbnail.jp

Using imprecise continuous time Markov chains for assessing the reliability of power networks with common cause failure and non-immediate repair

We explore how imprecise continuous time Markov chains can improve traditional reliability models based on precise continuous time Markov chains. Specifically, we analyse the reliability of power networks under very weak statistical assumptions, explicitly accounting for non-stationary failure and repair rates and the limited accuracy by which common cause failure rates can be estimated. Bounds on typical quantities of interest are derived, namely the expected time spent in system failure state, as well as the expected number of transitions to that state. A worked numerical example demonstrates the theoretical techniques described. Interestingly, the number of iterations required for convergence is observed to be much lower than current theoretical bounds

An equatorial wind from the massive young stellar object S140 IRS 1

The discovery of the second equatorial ionized stellar wind from a massive young stellar object is reported. High resolution radio continuum maps of S140 IRS 1 reveal a highly elongated source that is perpendicular to the larger scale bipolar molecular outflow. This picture is confirmed by location of a small scale monopolar near-IR reflection nebula at the base of the blueshifted lobe. A second epoch of observations over a five year baseline show little ordered outward proper motion of clumps as would have been expected for a jet. A third epoch, taken only 50 days after the second, did show significant changes in the radio morphology. These radio properties can all be understood in the context of an equatorial wind driven by radiation pressure from the central star and inner disc acting on the gas in the surface layers of the disc as proposed by Drew et al. (1998). This equatorial wind system is briefly compared with the one in S106IR, and contrasted with other massive young stellar objects that drive ionized jets.Comment: 19 pages, 5 figures, accepted by ApJ, minor changes in light of referees repor