27,035 research outputs found
Non-destructive spatial heterodyne imaging of cold atoms
We demonstrate a new method for non-destructive imaging of laser-cooled
atoms. This spatial heterodyne technique forms a phase image by interfering a
strong carrier laser beam with a weak probe beam that passes through the cold
atom cloud. The figure of merit equals or exceeds that of phase-contrast
imaging, and the technique can be used over a wider range of spatial scales. We
show images of a dark spot MOT taken with imaging fluences as low as 61 pJ/cm^2
at a detuning of 11 linewidths, resulting in 0.0004 photons scattered per atom.Comment: text+3 figures, submitted to Optics Letter
A slowly rotating perfect fluid body in an ambient vacuum
A global model of a slowly rotating perfect fluid ball in general relativity
is presented. To second order in the rotation parameter, the junction surface
is an ellipsoidal cylinder. The interior is given by a limiting case of the
Wahlquist solution, and the vacuum region is not asymptotically flat. The
impossibility of joining an asymptotically flat vacuum region has been shown in
a preceding work.Comment: 7 pages, published versio
Workforce development and effective evaluation of projects
Date of Acceptance: 01/05/2014The success of a project or programme is typically determined in relation to outputs. However, there is a commitment among UK public services to spending public funds efficiently and on activities that provide the greatest benefit to society. Skills for Health recognised the need for a tool to manage the complex process of evaluating project benefits. An integrated evaluation framework was developed to help practitioners identify, describe, measure and evaluate the benefits of workforce development projects. Practitioners tested the framework on projects within three NHS trusts and provided valuable feedback to support its development. The prospective approach taken to identify benefits and collect baseline data to support evaluation was positively received and the clarity and completeness of the framework, as well as the relevance of the questions, were commended. Users reported that the framework was difficult to complete; an online version could be developed, which might help to improve usability. Effective implementation of this approach will depend on the quality and usability of the framework, the willingness of organisations to implement it, and the presence or establishment of an effective change management culture.Peer reviewedFinal Accepted Versio
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Viral infections in interferon-gamma receptor deficiency.
Interferon-gamma receptor deficiency is a recently described immunodeficiency that is associated with onset of severe mycobacterial infections in childhood. We describe the occurrence of symptomatic and often severe viral infections in 4 patients with interferon-gamma receptor deficiency and mycobacterial disease. The viral pathogens included herpes viruses, parainfluenza virus type 3, and respiratory syncytial virus. We conclude that patients with interferon-gamma receptor deficiency and mycobacterial disease have increased susceptibility to some viral pathogens
Ground-State Properties of a Rotating Bose-Einstein Condensate with Attractive Interaction
The ground state of a rotating Bose-Einstein condensate with attractive
interaction in a quasi-one-dimensional torus is studied in terms of the ratio
of the mean-field interaction energy per particle to the
single-particle energy-level spacing. The plateaus of quantized circulation are
found to appear if and only if with the lengths of the plateaus
reduced due to hybridization of the condensate over different angular-momentum
states.Comment: 4 pages, 2 figures, Accepted for publication in Physical Reveiw
Letter
Symmetry-based approach to electron-phonon interactions in graphene
We use the symmetries of monolayer graphene to write a set of constraints
that must be satisfied by any electron-phonon interaction hamiltonian. The
explicit solution as a series expansion in the momenta gives the most general,
model-independent couplings between electrons and long wavelength acoustic and
optical phonons. As an application, the possibility of describing elastic
strains in terms of effective electromagnetic fields is considered in detail,
with an emphasis on group theory conditions and the role of time reversal
symmetry.Comment: 11 pages, 1 figure. Treatment of ripples in suspended graphene sheets
included. Revised journal version with improved presentation and two new
appendice
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