7,766 research outputs found
'Wrong' answers, right response: learning from randomised controlled trials when you don't get the results you were hoping for
United Kingdom minerals yearbook 2014 : statistical data to 2013
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
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
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
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
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
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
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Studies of Potential Inhibitors of Sodium Aluminosilicate Scales in High-Level Waste Evaporation
The Savannah River Site (SRS) has 49 underground storage tanks used to store High Level Waste (HLW). The tank space in these tanks must be managed to support the continued operation of key facilities. The reduction of the tank volumes in these tanks are accomplished through the use of three atmospheric pressure HLW evaporators. For a decade, evaporation of highly alkaline HLW containing aluminum and silicates has produced sodium aluminosilicate scales causing both operation and criticality hazards in the 2H Evaporator System. Segregation of aluminum-rich wastes from silicate-rich wastes minimizes the amount of scale produced and reduces cleaning expenses, but does not eliminate the scaling nor increases operation flexibility in waste process. Similar issues have affected the aluminum refining industry for many decades. Over the past several years, successful commercial products have been identified to eliminate aluminosilicate fouling in the aluminum industry, but have not been utilized in a nuclear environment. Laboratory quantities of three proprietary aluminosilicate scale inhibitors have been produced and been shown to prevent formation of scales. SRNL has been actively testing these potential inhibitors to examine their radiation stability, radiolytic degradation behaviors, and downstream impacts to determine their viability within the HLW system. One of the tested polymers successfully meets the established criteria for application in the nuclear environment. This paper will describe a summary of the methodology used to prioritize laboratory testing protocols based on potential impacts/risks identified for inhibitor deployment at SRS
Lifetime measurement of the metastable 3d 2D5/2 state in the 40Ca+ ion using the shelving technique on a few-ion string
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
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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