On the use of photobleaching to reduce fluorescence background in Raman spectroscopy to improve the reliability of pigment identification on painted textiles

Subjecting a specimen of red lead watercolour paint on silk to photobleaching was demonstrated to be a simple means by which to engineer a reduction in the magnitude of the fluorescent background that was approximately exponential with time, with a corresponding improvement in the signal to noise ratio of the Raman spectrum, thus rendering the characteristic peaks more easily visible and allowing more confident identification of the pigment. However, relative heights of the Raman peaks obtained from the sample were seen to alter progressively as a result of irradiation, indicating that some component of the sample was undergoing degradation that may result in longer-term damage to a fragile historic artefact. It was also shown that crystals of the lead monoxide pigment massicot were present in the samples ofred lead on a painted silk artefact dating from 1750. It is concluded that this was either due to deliberate mixing of pigments by the artist, contrary to historic records, or as a result of the roasting techniques used to create red lead pigments at the time and not due to thermal degradation of the pigment during Raman analysis

Leadership conversations: the impact on patient environments

Purpose – The aim of this study is to examine 15 NHS acute trusts in England that achieved high scores at all their hospitals in the first four national Patient Environment audits. No common external explanations were discernible. This paper seeks to examine whether the facilities managers responsible for the Patient Environment displayed a consistent leadership style. Design/methodology/approach – Overall, six of the 15 trusts gave permission for the research to take place and a series of unstructured interviews and observations were arranged with 22 facilities managers in these trusts. Responses were transcribed and categorised through multiple iteration. Findings – The research found common leadership and managerial behaviours, many of which could be identified from other literature. The research also identified managers deliberately devoting energy and time to creating networks of conversations. This creation of networks through managing conversation is behaviour less evident in mainstream leadership literature or in the current Department of Health and NHS leadership models. Practical implications – The findings of this study offer managers (particularly those in FM and managers across NHS) a unique insight into the potential impact of leaders giving an opportunity to re-model thinking on management and leadership and the related managerial development opportunities. It provides the leverage to move facilities management from the role of a commodity or support service, to a position as a true enabler of business. Originality/value – Original research is presented in a previously under-examined area. The paper illuminates how facilities management within trusts achieving high Patient Environment Action Team (PEAT) scores is led.</p

Faraday Conversion in Turbulent Blazar Jets

Low ($\lesssim 1\%$) levels of circular polarization (CP) detected at radio frequencies in the relativistic jets of some blazars can provide insight into the underlying nature of the jet plasma. CP can be produced through linear birefringence, in which initially linearly polarized emission produced in one region of the jet is altered by Faraday rotation as it propagates through other regions of the jet with varying magnetic field orientation. Marscher has begun a study of jets with such magnetic geometries using the Turbulent Extreme Multi-Zone (TEMZ) model, in which turbulent plasma crossing a standing shock in the jet is represented by a collection of thousands of individual plasma cells, each with distinct magnetic field orientations. Here we develop a radiative transfer scheme that allows the numerical TEMZ code to produce simulated images of the time-dependent linearly and circularly polarized intensity at different radio frequencies. In this initial study, we produce synthetic polarized emission maps that highlight the linear and circular polarization expected within the model.Comment: 17 pages, 13 figures, accepted for publication in Ap

Static highly elliptical orbits using hybrid low-thrust propulsion

Static highly-elliptical orbits enabled using hybrid solar-sail/solar-electric propulsion are investigated. These newly proposed orbits, termed Taranis orbits, have free selection of ‘critical inclination’ and use low-thrust propulsion to compensate for the drift in argument of perigee caused by Earth’s gravitational field. In this paper, a 12-hr Taranis orbit with an inclination of 90deg is developed to illustrate the principle. The acceleration required to enable this novel orbit is made up partly by the acceleration produced by solar-sails of various characteristic accelerations, and the remainder supplied by the electric thruster. Order of magnitude mission lifetimes are determined, a strawman mass budget is also developed for two system constraints, firstly spacecraft launch-mass is fixed, and secondly the maximum thrust of the thruster is constrained. Fixing maximum thrust increases mission lifetimes, and solar-sails are considered near to mid-term technologies. However, fixing mass results in negligible increases in mission lifetimes for all hybrid cases considered, solar sails also require significant development. This distinction highlights an important contribution to the field, illustrating that addition of a solar-sail to an electric propulsion craft can have negligible benefit when mass is the primary system constraint. Technology requirements are also outlined, including sizing of solar-arrays, propellant tanks and solar sails

Citizenship, community, and counter-terrorism : UK security discourse, 2001-2011

This paper analyses a corpus of UK policy documents which sets out national security policy as an exemplar of the contemporary discourse of counter-terrorism in Europe, the USA and worldwide. A corpus of 148 documents (c. 2.8 million words) was assembled to reflect the security discourse produced by the UK government before and after the 7/7 attacks on the London Transport system. To enable a chronological comparison, the two sub-corpora were defined: one relating to a discourse of citizenship and community cohesion (2001-2006); and one relating to the ‘Preventing Violent Extremism’ discourse (2007-2011). Wordsmith Tools (Scott 2008) was used to investigate keywords and patterns of collocation. The results present themes emerging from a comparative analysis of the 100 strongest keywords in each sub- corpus; as well as a qualitative analysis of related patterns of the collocation, focusing inparticular on features of connotation and semantic prosody

Suitability of post-Newtonian/numerical-relativity hybrid waveforms for gravitational wave detectors

This article presents a study of the sufficient accuracy of post-Newtonian and numerical relativity waveforms for the most demanding usage case: parameter estimation of strong sources in advanced gravitational wave detectors. For black hole binaries, these detectors require accurate waveform models which can be constructed by fusing an analytical post-Newtonian inspiral waveform with a numerical relativity merger-ringdown waveform. We perform a comprehensive analysis of errors that enter such "hybrid waveforms". We find that the post-Newtonian waveform must be aligned with the numerical relativity waveform to exquisite accuracy, about 1/100 of a gravitational wave cycle. Phase errors in the inspiral phase of the numerical relativity simulation must be controlled to less than about 0.1rad. (These numbers apply to moderately optimistic estimates about the number of GW sources; exceptionally strong signals require even smaller errors.) The dominant source of error arises from the inaccuracy of the investigated post-Newtonian Taylor-approximants. Using our error criterium, even at 3.5-th post-Newtonian order, hybridization has to be performed significantly before the start of the longest currently available numerical waveforms which cover 30 gravitational wave cycles. The current investigation is limited to the equal-mass, zero-spin case and does not take into account calibration errors of the gravitational wave detectors.Comment: 32 pages, 12 figures, submitted to CQG for the NRDA2010 conference proceedings, added new figure (fig. 5) since last versio