685 research outputs found

    Assessing the quality of written information provision for surgical procedures:A case study in oesophagectomy

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    OBJECTIVE: To examine the content and quality of written information provided by surgical centres for patients undergoing oesophagectomy for cancer. DESIGN: Cross-sectional study of the content of National Health Service (NHS) patient information leaflets (PILs) about oesophageal cancer surgery, using a modified framework approach. DATA SOURCES: Written information leaflets from 41 of 43 cancer centres undertaking surgery for oesophageal cancer in England and Wales (response rate 95.3%). ELIGIBILITY CRITERIA: All English language versions of PILs about oesophagectomy. RESULTS: 32 different PILs were identified, of which 2 were generic tools (Macmillan ‘understanding cancer of the gullet’ and EIDO ‘oesophagectomy’). Although most PILs focused on describing in-hospital adverse events, information varied widely and was often misleading. Just 1 leaflet described survival benefits of surgery and 2 mentioned the possibility of disease recurrence. CONCLUSIONS: Written information provided for patients by NHS cancer centres undertaking oesophagectomy is inconsistent and incomplete. It is recommended that surgeons work together with patients to agree on standards of information provision of relevance to all stakeholders’ needs

    Entanglement and decoherence of a micromechanical resonator via coupling to a Cooper box

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    We analyse the quantum dynamics of a micromechanical resonator capacitively coupled to a Cooper box. With appropriate quantum state control of the Cooper box, the resonator can be driven into a superposition of spatially separated states. The Cooper box can also be used to probe the environmentally-induced decoherence of the resonator superposition state.Comment: 4 pages, 3 figure

    Measurement induced quantum-classical transition

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    A model of an electrical point contact coupled to a mechanical system (oscillator) is studied to simulate the dephasing effect of measurement on a quantum system. The problem is solved at zero temperature under conditions of strong non-equilibrium in the measurement apparatus. For linear coupling between the oscillator and tunneling electrons, it is found that the oscillator dynamics becomes damped, with the effective temperature determined by the voltage drop across the junction. It is demonstrated that both the quantum heating and the quantum damping of the oscillator manifest themselves in the current-voltage characteristic of the point contact.Comment: in RevTex, 1 figure, corrected notatio

    Nonlinear response of a driven vibrating nanobeam in the quantum regime

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    We analytically investigate the nonlinear response of a damped doubly clamped nanomechanical beam under static longitudinal compression which is excited to transverse vibrations. Starting from a continuous elasticity model for the beam, we consider the dynamics of the beam close to the Euler buckling instability. There, the fundamental transverse mode dominates and a quantum mechanical time-dependent effective single particle Hamiltonian for its amplitude can be derived. In addition, we include the influence of a dissipative Ohmic or super-Ohmic environment. In the rotating frame, a Markovian master equation is derived which includes also the effect of the time-dependent driving in a non-trivial way. The quasienergies of the pure system show multiple avoided level crossings corresponding to multiphonon transitions in the resonator. Around the resonances, the master equation is solved analytically using Van Vleck perturbation theory. Their lineshapes are calculated resulting in simple expressions. We find the general solution for the multiple multiphonon resonances and, most interestingly, a bath-induced transition from a resonant to an antiresonant behavior of the nonlinear response.Comment: 25 pages, 5 figures, submitted to NJ

    Steering of a Bosonic Mode with a Double Quantum Dot

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    We investigate the transport and coherence properties of a double quantum dot coupled to a single damped boson mode. Our numerically results reveal how the properties of the boson distribution can be steered by altering parameters of the electronic system such as the energy difference between the dots. Quadrature amplitude variances and the Wigner function are employed to illustrate how the state of the boson mode can be controlled by a stationary electron current through the dots.Comment: 10 pages, 6 figures, to appear in Phys. Rev.

    Discussing surgical innovation with patients: A qualitative study of surgeons’ and governance representatives’ views

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    Objectives Little is known about how innovative surgical procedures are introduced and discussed with patients. This qualitative study aimed to explore perspectives on information provision and consent prior to innovative surgical procedures.Design Qualitative study involving semi-structured interviews. Interviews were audio recorded, transcribed and analysed thematically.Participants 42 interviews were conducted (26 surgeons and 16 governance representatives).Setting Surgeons and governance representatives recruited from various surgical specialties and National Health Service (NHS) Trusts across England, UK.Results Participants stated that if a procedure was innovative, patients should be provided with additional information extending beyond that given during routine surgical consultations. However, difficulty defining innovation had implications for whether patients were informed about novel components of surgery and how the procedure was introduced (ie, as part of a research study, trust approval or in routine clinical practice). Furthermore, data suggest surgeons found it difficult to establish what information is essential and how much detail is sufficient, and governance surrounding written and verbal information provision differed between NHS Trusts. Generally, surgeons believed patients held a view that ‘new’ was best and reported that managing these expectations could be difficult, particularly if patient views aligned with their own.Conclusions This study highlights the challenges of information provision and obtaining informed consent in the context of innovative surgery, including establishing if and how a procedure is truly innovative, determining the key information to discuss with patients, ensuring information provision is objective and balanced, and managing patient expectations and preferences. This suggests that surgeons may require support and training to discuss novel procedures with patients. Further work should capture consultations where new procedures are discussed with patients and patients’ views of these information exchanges

    On the eigenproblems of PT-symmetric oscillators

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    We consider the non-Hermitian Hamiltonian H= -\frac{d^2}{dx^2}+P(x^2)-(ix)^{2n+1} on the real line, where P(x) is a polynomial of degree at most n \geq 1 with all nonnegative real coefficients (possibly P\equiv 0). It is proved that the eigenvalues \lambda must be in the sector | arg \lambda | \leq \frac{\pi}{2n+3}. Also for the case H=-\frac{d^2}{dx^2}-(ix)^3, we establish a zero-free region of the eigenfunction u and its derivative u^\prime and we find some other interesting properties of eigenfunctions.Comment: 21pages, 9 figure
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