Panphasia: a user guide

We make a very large realisation of a Gaussian white noise field, called PANPHASIA, public by releasing software that computes this field. Panphasia is designed specifically for setting up Gaussian initial conditions for cosmological simulations and resimulations of structure formation. We make available both software to compute the field itself and codes to illustrate applications including a modified version of a public serial initial conditions generator. We document the software and present the results of a few basic tests of the field. The properties and method of construction of Panphasia are described in full in a companion paper Jenkins 2013.Comment: 11 pages, 2 figures. Software to calculate Panphasia is available from: http://icc.dur.ac.uk/Panphasia.ph

Canonical Phase Space Formulation of Quasilocal General Relativity

We construct a Hamiltonian formulation of quasilocal general relativity using an extended phase space that includes boundary coordinates as configuration variables. This allows us to use Hamiltonian methods to derive an expression for the energy of a non-isolated region of space-time that interacts with its neighbourhood. This expression is found to be very similar to the Brown-York quasilocal energy that was originally derived by Hamilton-Jacobi methods. We examine the connection between the two formalisms and find that when the boundary conditions for the two are harmonized, the resulting quasilocal energies are identical.Comment: 31 pages, 2 figures, references added, typos corrected, section 3 revised for clarity, to appear in Classical and Quantum Gravit

The first law for slowly evolving horizons

We study the mechanics of Hayward's trapping horizons, taking isolated horizons as equilibrium states. Zeroth and second laws of dynamic horizon mechanics come from the isolated and trapping horizon formalisms respectively. We derive a dynamical first law by introducing a new perturbative formulation for dynamic horizons in which "slowly evolving" trapping horizons may be viewed as perturbatively non-isolated.Comment: 4 pages, typos fixed, minor changes in wording for clarity, to appear in PR

The European Parliament is a failed experiment in pan-European democracy – national parliaments are the key to solving the democratic deficit

Strengthening the European Parliament has often been viewed as the best method of addressing the EU’s alleged ‘democratic deficit’. Stephen Booth writes that while this perspective has led to the Parliament’s powers being increased successively over recent decades, the effect of these reforms on democratic engagement among EU citizens has been limited. He argues that boosting the role of national parliaments in the EU legislative process would offer a far better route for returning democratic accountability closer to voters

Extremality conditions for isolated and dynamical horizons

A maximally rotating Kerr black hole is said to be extremal. In this paper we introduce the corresponding restrictions for isolated and dynamical horizons. These reduce to the standard notions for Kerr but in general do not require the horizon to be either stationary or rotationally symmetric. We consider physical implications and applications of these results. In particular we introduce a parameter e which characterizes how close a horizon is to extremality and should be calculable in numerical simulations.Comment: 13 pages, 4 figures, added reference; v3 appendix added with proof of result from section IIID, some discussion and references added. Version to appear in PR

Expert systems for fault analysis

The initial aim of this research was to investigate the application of expert Systems, or Knowledge Base Systems technology to the automated synthesis of Hazard and Operability Studies. Due to the generic nature of Fault Analysis problems and the way in which Knowledge Base Systems work, this goal has evolved into a consideration of automated support for Fault Analysis in general, covering HAZOP, Fault Tree Analysis, FMEA and Fault Diagnosis in the Process Industries. This thesis described a proposed architecture for such an Expert System. The purpose of the System is to produce a descriptive model of faults and fault propagation from a description of the physical structure of the plant. From these descriptive models, the desired Fault Analysis may be produced. The way in which this is done reflects the complexity of the problem which, in principle, encompasses the whole of the discipline of Process Engineering. An attempt is made to incorporate the perceived method that an expert uses to solve the problem; keywords, heuristics and guidelines from techniques such as HAZOP and Fault Tree Synthesis are used. In a truly Expert System, the performance of the system is strongly dependent on the high quality of the knowledge that is incorporated. This expert knowledge takes the form of heuristics or rules of thumb which are used in problem solving. This research has shown that, for the application of fault analysis heuristics, it is necessary to have a representation of the details of fault propagation within a process. This helps to ensure the robustness of the system - a gradual rather than abrupt degradation at the boundaries of the domain knowledge

Isolated, slowly evolving, and dynamical trapping horizons: geometry and mechanics from surface deformations

We study the geometry and dynamics of both isolated and dynamical trapping horizons by considering the allowed variations of their foliating two-surfaces. This provides a common framework that may be used to consider both their possible evolutions and their deformations as well as derive the well-known flux laws. Using this framework, we unify much of what is already known about these objects as well as derive some new results. In particular we characterize and study the "almost-isolated" trapping horizons known as slowly evolving horizons. It is for these horizons that a dynamical first law holds and this is analogous and closely related to the Hawking-Hartle formula for event horizons.Comment: 39 pages, 6 figures, version to appear in PRD : a few minor changes and many typos corrected in equation

Embodied Resilience: Supervising/Mentoring during a Time of COVID-19, Black Lives Matter, and Climate Change

The authors take on the task of addressing three of the most significant issues in our society today and how one functions as a mentor and supervisor