13,045 research outputs found
Optimizing diagnostic imaging through skills mix: costs and opportunities
YesIncreasing diagnostic capacity is a national priority to expedite the timeliness and appropriateness of patient treatment interventions. Imaging, encompassing a range of technologies including X-ray, Computer Tomography, Magnetic Resonance Imaging and ultrasound, is a key diagnostic service and central to decision making in most, if not all, disease pathways. However, imaging is an expensive discipline accounting for an estimated 3-5% of the annual NHS budget. As a result, it is imperative that we maximize service efficiency while optimizing patient outcomes
Discriminating quantum-optical beam-splitter channels with number-diagonal signal states: Applications to quantum reading and target detection
We consider the problem of distinguishing, with minimum probability of error,
two optical beam-splitter channels with unequal complex-valued reflectivities
using general quantum probe states entangled over M signal and M' idler mode
pairs of which the signal modes are bounced off the beam splitter while the
idler modes are retained losslessly. We obtain a lower bound on the output
state fidelity valid for any pure input state. We define number-diagonal signal
(NDS) states to be input states whose density operator in the signal modes is
diagonal in the multimode number basis. For such input states, we derive series
formulas for the optimal error probability, the output state fidelity, and the
Chernoff-type upper bounds on the error probability. For the special cases of
quantum reading of a classical digital memory and target detection (for which
the reflectivities are real valued), we show that for a given input signal
photon probability distribution, the fidelity is minimized by the NDS states
with that distribution and that for a given average total signal energy N_s,
the fidelity is minimized by any multimode Fock state with N_s total signal
photons. For reading of an ideal memory, it is shown that Fock state inputs
minimize the Chernoff bound. For target detection under high-loss conditions, a
no-go result showing the lack of appreciable quantum advantage over coherent
state transmitters is derived. A comparison of the error probability
performance for quantum reading of number state and two-mode squeezed vacuum
state (or EPR state) transmitters relative to coherent state transmitters is
presented for various values of the reflectances. While the nonclassical states
in general perform better than the coherent state, the quantitative performance
gains differ depending on the values of the reflectances.Comment: 12 pages, 7 figures. This closely approximates the published version.
The major change from v2 is that Section IV has been re-organized, with a
no-go result for target detection under high loss conditions highlighted. The
last sentence of the abstract has been deleted to conform to the arXiv word
limit. Please see the PDF for the full abstrac
Embedding consultant radiographer roles within radiology departments: a framework for success
Introduction: Many organisations struggle to clearly differentiate the radiographer consultant role from advanced or specialist practice, with newly appointed consultant practitioners often ill-prepared for working at this level. This article discusses the design, implementation and validation of an outcomes framework for benchmarking competencies for trainee or new-in-post consultant radiographers. Methods: Five experienced radiographers from different clinical specialisms were seconded to a twelve month consultant trainee post, guided by a locally-devised outcomes framework. A longitudinal qualitative study explored, from the radiographers’ perspective, the impact of the outcomes framework on the transition to consultant practice and beyond. Data collection included semi-structured interviews (months 1, 6 and 12), validation via a focus group (month 18) and a group interview (5 years). Results: Early interactions with framework objectives were mechanistic, but as participants better understood the role more creative approaches emerged. Despite diverse clinical expertise, the framework facilitated parity between participants, promoting transparency and credibility which was important in how the consultant role was perceived. All participants achieved all framework outcomes and were subsequently appointed to substantive consultant radiographer positions. Conclusion: This outcomes framework facilitates experienced radiographers to successfully transition into consultant radiographers, enabling them to meet multiple non-clinical targets while continuing to work effectively within a changing clinical environment. It is the first validated benchmarking tool designed to support the transition to radiographer consultant practice. Adoption of the tool will provide a standardised measure of consultant radiographer outcomes that will promote inter-organisational transferability hitherto unseen in the U
Langmuir Wave Generation Through A Neutrino Beam Instability
A standard version of a kinetic instability for the generation of Langmuir
waves by a beam of electrons is adapted to describe the analogous instability
due to a beam of neutrinos. The interaction between a Langmuir wave and a
neutrino is treated in the one-loop approximation to lowest order in an
expansion in in the standard electroweak model.
It is shown that this kinetic instability is far too weak to occur in a
suggested application to the reheating of the plasma behind a stalled shock in
a type II supernova (SN). This theory is also used to test the validity of a
previous analysis of a reactive neutrino beam instability and various
shortcomings of this theory are noted. In particular, it is noted that
relativistic plasma effects have a significant effect on the calculated growth
rates, and that any theoretical description of neutrino-plasma interactions
must be based directly on the electroweak theory. The basic scalings discussed
in this paper suggest that a more complete investigation of neutrino-plasma
processes should be undertaken to look for an efficient process capable of
driving the stalled shock of a type II SN.Comment: 23 pages, incl. 5 postscript figure
A method to find unstable periodic orbits for the diamagnetic Kepler Problem
A method to determine the admissibility of symbolic sequences and to find the
unstable periodic orbits corresponding to allowed symbolic sequences for the
diamagnetic Kepler problem is proposed by using the ordering of stable and
unstable manifolds. By investigating the unstable periodic orbits up to length
6, a one to one correspondence between the unstable periodic orbits and their
corresponding symbolic sequences is shown under the system symmetry
decomposition
- …