Warrior vehicle fleet sustainment using intelligent agent simulation

2nd International Through-Life Engineering Services Conference (TESConf 2013), 5-6 November 2013, Cranfield University, Bedfordshire, UKThe Warrior Infantry Fighting Vehicle(IFV) is one of the key tracked combat vehicles in the UK Army. It was first introduced in 1988. A modernisation programme is currently underway to enhance 643 vehicles to serve to 2040 and beyond. The Warrior is typical of military assets that have to be acquired, maintained, supported and deployed. Effective materials and logistics support for the life of the asset is necessary to give the army a capability to defend the country and keep world peace. In the military world, events are uncertain. An asset can be used relatively lightly in peace time for training and readiness preparation. When it is deployed, it is used intensely and probably in situations not foreseen in the original design specification. Compared with a commercial vehicle that is designed to be continuously heavily used, military uncertainties make the planning for spares and repairs very difficult. Responding to the dynamics of military logistics, inventory planners have to make decisions on how many spares to order from the manufacturer and when, where to store the spares, and when to send them to the units. Maintenance decisions are also made by military engineers to pull vehicles into depots for scheduled maintenance, deal with unexpected repairs, and make sure all people, equipment and spares are coordinated for the maintenance work. Planning for the worst case scenarios provides enhanced resilience to military needs, but is likely to be unnecessarily costly. Compared with an inventory management problem that has steady demand and supply, optimal military logistics could be better served by adapting the behaviour of the planners to suit the dynamics of the deployment scenarios. This paper reports on a military logistics sustainment model built using an agent based simulation platform, with the Warrior vehicle fleet as the case study. The model proves an effective tool to help military planners evaluate different spares inventory policies to match deployment demands

Causality constraints in AdS/CFT from conformal collider physics and Gauss-Bonnet gravity

We explore the relation between positivity of the energy constraints in conformal field theories and causality in their dual gravity description. Our discussion involves CFTs with different central charges whose description, in the gravity side, requires the inclusion of quadratic curvature corrections. It is enough, indeed, to consider the Gauss-Bonnet term. We find that both sides of the AdS/CFT correspondence impose a restriction on the Gauss-Bonnet coupling. In the case of 6d supersymmetric CFTs, we show the full matching of these restrictions. We perform this computation in two ways. First by considering a thermal setup in a black hole background. Second by scrutinizing the scattering of gravitons with a shock wave in AdS. The different helicities provide the corresponding lower and upper bounds. We generalize these results to arbitrary higher dimensions and comment on some hints and puzzles they prompt regarding the possible existence of higher dimensional CFTs and the extent to which the AdS/CFT correspondence would be valid for them.Comment: 31 pages, 5 figures; v2: typos fixed, cosmetic amendments and references adde

Black Holes in Quasi-topological Gravity

We construct a new gravitational action which includes cubic curvature interactions and which provides a useful toy model for the holographic study of a three parameter family of four- and higher-dimensional CFT's. We also investigate the black hole solutions of this new gravity theory. Further we examine the equations of motion of quasi-topological gravity. While the full equations in a general background are fourth-order in derivatives, we show that the linearized equations describing gravitons propagating in the AdS vacua match precisely the second-order equations of Einstein gravity.Comment: 33 pages, 4 figures; two references adde

Replication fork reversal and the maintenance of genome stability

The progress of replication forks is often threatened in vivo, both by DNA damage and by proteins bound to the template. Blocked forks must somehow be restarted, and the original blockage cleared, in order to complete genome duplication, implying that blocked fork processing may be critical for genome stability. One possible pathway that might allow processing and restart of blocked forks, replication fork reversal, involves the unwinding of blocked forks to form four-stranded structures resembling Holliday junctions. This concept has gained increasing popularity recently based on the ability of such processing to explain many genetic observations, the detection of unwound fork structures in vivo and the identification of enzymes that have the capacity to catalyse fork regression in vitro. Here, we discuss the contexts in which fork regression might occur, the factors that may promote such a reaction and the possible roles of replication fork unwinding in normal DNA metabolism

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Identifying non-stationary groundwater level response to North Atlantic ocean- atmosphere teleconnection patterns using wavelet coherence

The first comprehensive use of wavelet methods to identify non-stationary time- frequency relations between North Atlantic ocean-atmosphere teleconnection patterns and groundwater levels is described. Long-term hydrogeological time series from three boreholes within different aquifers across the UK are analysed to identify statistically significant wavelet coherence between the North Atlantic Oscillation, East Atlantic pattern, and the Scandinavia pattern and monthly groundwater-level time series. Wavelet coherence measures the cross- correlation of two time series as a function of frequency, and can be interpreted as a correlation coefficient value. Results not only indicate that there are common statistically significant periods of multiannual-to-decadal wavelet coherence between the three teleconnection indices and groundwater levels in each of the boreholes, but they also show that there are periods when groundwater levels at individual boreholes show distinctly different patterns of significant wavelet coherence with respect to the teleconnection indices. The analyses presented demonstrate the value of wave- let methods in identifying the synchronization of groundwater-level dynamics by non-stationary climate variability on time scales that range from interannual to decada