7,766 research outputs found

    United Kingdom minerals yearbook 2014 : statistical data to 2013

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    The United Kingdom Minerals Yearbook is an annual publication providing comprehensive statistical data on minerals production, consumption and trade, and includes commentary on the UK's minerals industry. It contains: • essential guidance for decision makers • reliable and up–to–date information • authoritative commentary on current developments It is of value to all those interested in the many facets of Britain's minerals industry and its contribution to the national economy. This publication forms part of Britain's continuous mining and quarrying record

    United Kingdom Minerals Yearbook 2013 : statistical data to 2012

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    The compilers of this volume are grateful for the help received from the Office for National Statistics, the Department for Business, Innovation and Skills, the Department for Communities and Local Government, the Department of Energy and Climate Change, the Crown Estate Commissioners, The Crown Mineral Agent, the Northern Ireland Department of Enterprise, Trade and Investment and the Isle of Man Department of Trade and Industry. They would also like to acknowledge the valuable assistance given by the World Bureau of Metal Statistics, the UK Iron and Steel Statistics Bureau, the Mineral Products Association, The Coal Authority and the numerous companies that have generously provided additional information

    Tempo2, a new pulsar timing package. II: The timing model and precision estimates

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    Tempo2 is a new software package for the analysis of pulsar pulse times of arrival. In this paper we describe in detail the timing model used by tempo2, and discuss limitations on the attainable precision. In addition to the intrinsic slow-down behaviour of the pulsar, tempo2 accounts for the effects of a binary orbital motion, the secular motion of the pulsar or binary system, interstellar, Solar system and ionospheric dispersion, observatory motion (including Earth rotation, precession, nutation, polar motion and orbital motion), tropospheric propagation delay, and gravitational time dilation due to binary companions and Solar system bodies. We believe the timing model is accurate in its description of predictable systematic timing effects to better than one nanosecond, except in the case of relativistic binary systems where further theoretical development is needed. The largest remaining sources of potential error are measurement error, interstellar scattering, Solar system ephemeris errors, atomic clock instability and gravitational waves.Comment: 30 pages, 3 figures, accepted for publication in MNRA

    From breathless to failure:symptom onset and diagnostic meaning in patients with heart failure - a qualitative study

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    Objectives: To explore 2 key points in the heart failure diagnostic pathway-symptom onset and diagnostic meaning-from the patient perspective. Design: Qualitative interview study. Setting: Participants were recruited from a secondary care clinic in central England following referral from primary care. Participants: Over age 55 years with a recent (<1 year) diagnosis of heart failure confirmed by a cardiologist following initial presentation to primary care. Methods: Semistructured interviews were carried out with 16 participants (11 men and 5 women, median age 78.5 years) in their own homes. Data were audiorecorded and transcribed. Participants were asked to describe their diagnostic journey from when they first noticed something wrong up to and including the point of diagnosis. Data were analysed using the framework method. Results: Participants initially normalised symptoms and only sought medical help when daily activities were affected. Failure to realise that anything was wrong led to a delay in help-seeking. Participants' understanding of the term 'heart failure' was variable and 1 participant did not know he had the condition. The term itself caused great anxiety initially but participants learnt to cope with and accept their diagnosis over time. Conclusions: Greater public awareness of symptoms and adequate explanation of 'heart failure' as a diagnostic label, or reconsideration of its use, are potential areas of service improvement

    TEMPO2, a new pulsar timing package. I: Overview

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    Contemporary pulsar timing experiments have reached a sensitivity level where systematic errors introduced by existing analysis procedures are limiting the achievable science. We have developed tempo2, a new pulsar timing package that contains propagation and other relevant effects implemented at the 1ns level of precision (a factor of ~100 more precise than previously obtainable). In contrast with earlier timing packages, tempo2 is compliant with the general relativistic framework of the IAU 1991 and 2000 resolutions and hence uses the International Celestial Reference System, Barycentric Coordinate Time and up-to-date precession, nutation and polar motion models. Tempo2 provides a generic and extensible set of tools to aid in the analysis and visualisation of pulsar timing data. We provide an overview of the timing model, its accuracy and differences relative to earlier work. We also present a new scheme for predictive use of the timing model that removes existing processing artifacts by properly modelling the frequency dependence of pulse phase.Comment: Accepted by MNRA

    A possible signature of cosmic neutrino decoupling in the nHz region of the spectrum of primordial gravitational waves

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    In this paper we study the effect of cosmic neutrino decoupling on the spectrum of cosmological gravitational waves (GWs). At temperatures T>>1 MeV, neutrinos constitute a perfect fluid and do not hinder GW propagation, while for T<<1 MeV they free-stream and have an effective viscosity that damps cosmological GWs by a constant amount. In the intermediate regime, corresponding to neutrino decoupling, the damping is frequency-dependent. GWs entering the horizon during neutrino decoupling have a frequency f ~ 1 nHz, corresponding to a frequency region that will be probed by Pulsar Timing Arrays (PTAs). In particular, we show how neutrino decoupling induces a spectral feature in the spectrum of cosmological GWs just below 1 nHz. We briefly discuss the conditions for a detection of this feature and conclude that it is unlikely to be observed by PTAs.Comment: 11 pages, 2 figures. V2: References Adde

    Lifetime measurement of the metastable 3d 2D5/2 state in the 40Ca+ ion using the shelving technique on a few-ion string

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    We present a measurement of the lifetime of the metastable 3d 2D5/2 state in the 40Ca+ ion, using the so-called shelving technique on a string of five Doppler laser-cooled ions in a linear Paul trap. A detailed account of the data analysis is given, and systematic effects due to unwanted excitation processes and collisions with background gas atoms are discussed and estimated. From a total of 6805 shelving events, we obtain a lifetime tau=1149+/-14(stat.)+/-4(sys.)ms, a result which is in agreement with the most recent measurements.Comment: 10 pages, 7 figures. Submitted for publicatio

    Observation of second-harmonic generation induced by pure spin currents

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    Extensive efforts are currently being devoted to developing a new electronic technology, called spintronics, where the spin of electrons is explored to carry information. [1,2] Several techniques have been developed to generate pure spin currents in many materials and structures. [3-10] However, there is still no method available that can be used to directly detect pure spin currents, which carry no net charge current and no net magnetization. Currently, studies of pure spin currents rely on measuring the induced spin accumulation with optical techniques [5, 11-13] or spin-valve configurations. [14-17] However, the spin accumulation does not directly reflect the spatial distribution or temporal dynamics of the pure spin current, and therefore cannot monitor the pure spin current in a real-time and real-space fashion. This imposes severe constraints on research in this field. Here we demonstrate a second-order nonlinear optical effect of the pure spin current. We show that such a nonlinear optical effect, which has never been explored before, can be used for the non-invasive, non-destructive, and real-time imaging of pure spin currents. Since this detection scheme does not rely on optical resonances, it can be generally applied in a wide range of materials with different electronic bandstructures. Furthermore, the control of nonlinear optical properties of materials with pure spin currents may have potential applications in photonics integrated with spintronics.Comment: 19 pages, 3 figures, supplementary discussion adde
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