Crossover from hydrodynamic to acoustic drag on quartz tuning forks in normal and superfluid 4He

We present measurements of the drag forces on quartz tuning forks oscillating at low velocities in normal and superfluid 4He. We have investigated the dissipative drag over a wide range of frequencies, from 6.5 to 600 kHz, by using arrays of forks with varying prong lengths and by exciting the forks in their fundamental and first overtone modes. At low frequencies the behavior is dominated by laminar hydrodynamic drag, governed by the fluid viscosity. At higher frequencies acoustic drag is dominant and is described well by a three-dimensional model of sound emission

Lanthanum halide nanoparticle scintillators for nuclear radiation detection

Nanoparticles with sizesscintillators, in order to determine the viability of using scintillators employing nanostructured lanthanum trifluoride. Preliminary results of this investigation are consistent with the idea that these materials have an intrinsic response to nuclear radiation that may be correlated to the energy of the incident radiation

Frequency-dependent drag from quantum turbulence produced by quartz tuning forks in superfluid He4

We have measured the drag force from quantum turbulence on a series of quartz tuning forks in superfluid helium. The tuning forks were custom made from a 75-μm-thick wafer. They have identical prong widths and prong spacings, but different lengths to give different resonant frequencies. We have used both the fundamental and overtone flexure modes to probe the turbulent drag over a broad range of frequencies f=ω/2π from 6.5 to 300 kHz. Optical measurements show that the velocity profiles of the flexure modes are well described by a cantilever beam model. The critical velocity for the onset of quantum turbulence at low temperatures is measured to be vc≈0.7κω−−−−−√ where κ is the circulation quantum. The drag from quantum turbulence shows a small frequency dependence when plotted against the scaled velocity v/v

Probing Bogoliubov Quasiparticles in Superfluid 3He with a ‘Vibrating-Wire Like’ MEMS Device

International audienceWe have measured the interaction between superfluid 3 He-B and a micro-machined goalpost-shaped device at temperatures below 0.2 T c. The measured damping follows well the theory developed for vibrating wires, in which the An-dreev reflection of quasiparticles in the flow field around the moving structure leads to a nonlinear frictional force. At low velocities the damping force is proportional to velocity while it tends to saturate for larger excitations. Above a velocity of 2.6 mms −1 the damping abruptly increases, which is interpreted in terms of Cooper-pair breaking. Interestingly, this critical velocity is significantly lower than reported with other mechanical probes immersed in superfluid 3 He. Furthermore , we report on a nonlinear resonance shape for large motion amplitudes that we interpret as an inertial effect due to quasiparticle friction, but other mechanisms could possibly be invoked as well. PACS numbers: 85.85.+j, 67.30.H-, 67.30.e

A quasiparticle detector for imaging quantum turbulence in superfluid 3He-B

We describe the development of a two-dimensional quasiparticle detector for use in visualising quantum turbulence in superfluid 3He-B at ultra-low temperatures. The detector consists of a 5×5 matrix of pixels, each a 1mm diameter hole in a copper block containing aminiature quartz tuning fork. The damping on each fork provides a measure of the local quasiparticle flux. The detector is illuminated by a beam of ballistic quasiparticles generated from a nearby black-body radiator. A comparison of the damping on the different forks provides a measure of the cross-sectional profile of the beam. Further, we generate a tangle of vortices (quantum turbulence) in the path of the beam using a vibrating wire resonator. The vortices cast a shadow onto the face of the detector due to the Andreev reflection of quasiparticles in the beam. This allows us to image the vortices and to investigate their dynamics. Here we give details of the design and construction of the detector and show some preliminary results for one row of pixels which demonstrates its successful application tomeasuring quasiparticle beams and quantum turbulence

Dust Reverberation Mapping and Light-Curve Modelling of Zw229-015

Multiwavelength variability studies of active galactic nuclei (AGN) can be used to probe their inner regions which are not directly resolvable. Dust reverberation mapping (DRM) estimates the size of the dust emitting region by measuring the delays between the infrared (IR) response to variability in the optical light curves. We measure DRM lags of Zw229-015 between optical ground-based and Kepler light curves and concurrent IR Spitzer 3.6 and 4.5 $\mu$m light curves from 2010-2015, finding an overall mean rest-frame lag of 18.3 $\pm$ 4.5 days. Each combination of optical and IR light curve returns lags that are consistent with each other within 1$\sigma$, which implies that the different wavelengths are dominated by the same hot dust emission. The lags measured for Zw229-015 are found to be consistently smaller than predictions using the lag-luminosity relationship. Also, the overall IR response to the optical emission actually depends on the geometry and structure of the dust emitting region as well, so we use Markov chain Monte Carlo (MCMC) modelling to simulate the dust distribution to further estimate these structural and geometrical properties. We find that a large increase in flux between the 2011-2012 observation seasons, which is more dramatic in the IR light curve, is not well simulated by a single dust component. When excluding this increase in flux, the modelling consistently suggests that the dust is distributed in an extended flat disk, and finds a mean inclination angle of 49$^{+3}_{-13}$ degrees.Comment: 32 pages, 32 Figures, 7 Tables; Accepted for publication in MNRA

Exchange Gate on the Qudit Space and Fock Space

We construct the exchange gate with small elementary gates on the space of qudits, which consist of three controlled shift gates and three "reverse" gates. This is a natural extension of the qubit case. We also consider a similar subject on the Fock space, but in this case we meet with some different situation. However we can construct the exchange gate by making use of generalized coherent operator based on the Lie algebra su(2) which is a well--known method in Quantum Optics. We moreover make a brief comment on "imperfect clone".Comment: Latex File, 12 pages. I could solve the problems in Sec. 3 in the preceding manuscript, so many corrections including the title were mad

Multilevel influences on resilient healthcare in six countries: an international comparative study protocol.

INTRODUCTION: Resilient healthcare (RHC) is an emerging area of theory and applied research to understand how healthcare organisations cope with the dynamic, variable and demanding environments in which they operate, based on insights from complexity and systems theory. Understanding adaptive capacity has been a focus of RHC studies. Previous studies clearly show why adaptations are necessary and document the successful adaptive actions taken by clinicians. To our knowledge, however, no studies have thus far compared RHC across different teams and countries. There are gaps in the research knowledge related to the multilevel nature of resilience across healthcare systems and the team-based nature of adaptive capacity.This cross-country comparative study therefore aims to add knowledge of how resilience is enabled in diverse healthcare systems by examining adaptive capacity in hospital teams in six countries. The study will identify how team, organisational and national healthcare system factors support or hinder the ability of teams to adapt to variability and change. Findings from this study are anticipated to provide insights to inform the design of RHC systems by considering how macro-level and meso-level structures support adaptive capacity at the micro-level, and to develop guidance for organisations and policymakers. METHODS AND ANALYSIS: The study will employ a multiple comparative case study design of teams nested within hospitals, in turn embedded within six countries: Australia, Japan, the Netherlands, Norway, Switzerland and the UK. The design will be based on the Adaptive Teams Framework placing adaptive teams at the centre of the healthcare system with layers of environmental, organisational and system level factors shaping adaptive capacity. In each of the six countries, a focused mapping of the macro-level features of the healthcare system will be undertaken by using documentary sources and interviews with key informants operating at the macro-level.A sampling framework will be developed to select two hospitals in each country to ensure variability based on size, location and teaching status. Four teams will be selected in each hospital-one each of a structural, hybrid, responsive and coordinating team. A total of eight teams will be studied in each country, creating a total sample of 48 teams. Data collection methods will be observations, interviews and document analysis. Within-case analysis will be conducted according to a standardised template using a combination of deductive and inductive qualitative coding, and cross-case analysis will be conducted drawing on the Qualitative Comparative Analysis framework. ETHICS AND DISSEMINATION: The overall Resilience in Healthcare research programme of which this study is a part has been granted ethical approval by the Norwegian Centre for Research Data (Ref. No. 8643334 and Ref. No. 478838). Ethical approval will also be sought in each country involved in the study according to their respective regulatory procedures. Country-specific reports of study outcomes will be produced for dissemination online. A collection of case study summaries will be made freely available, translated into multiple languages. Brief policy communications will be produced to inform policymakers and regulators about the study results and to facilitate translation into practice. Academic dissemination will occur through publication in journals specialising in health services research. Findings will be presented at academic, policy and practitioner conferences, including the annual RHC Network meeting and other healthcare quality and safety conferences. Presentations at practitioner and academic conferences will include workshops to translate the findings into practice and influence quality and safety programmes internationally

Protocol for the development of guidance for stakeholder engagement in health and healthcare guideline development and implementation

Stakeholder engagement has become widely accepted as a necessary component of guideline development and implementation. While frameworks for developing guidelines express the need for those potentially affected by guideline recommendations to be involved in their development, there is a lack of consensus on how this should be done in practice. Further, there is a lack of guidance on how to equitably and meaningfully engage multiple stakeholders. We aim to develop guidance for the meaningful and equitable engagement of multiple stakeholders in guideline development and implementation. METHODS: This will be a multi-stage project. The first stage is to conduct a series of four systematic reviews. These will (1) describe existing guidance and methods for stakeholder engagement in guideline development and implementation, (2) characterize barriers and facilitators to stakeholder engagement in guideline development and implementation, (3) explore the impact of stakeholder engagement on guideline development and implementation, and (4) identify issues related to conflicts of interest when engaging multiple stakeholders in guideline development and implementation. DISCUSSION: We will collaborate with our multiple and diverse stakeholders to develop guidance for multi-stakeholder engagement in guideline development and implementation. We will use the results of the systematic reviews to develop a candidate list of draft guidance recommendations and will seek broad feedback on the draft guidance via an online survey of guideline developers and external stakeholders. An invited group of representatives from all stakeholder groups will discuss the results of the survey at a consensus meeting which will inform the development of the final guidance papers. Our overall goal is to improve the development of guidelines through meaningful and equitable multi-stakeholder engagement, and subsequently to improve health outcomes and reduce inequities in health

A web-based library consult service for evidence-based medicine: Technical development

BACKGROUND: Incorporating evidence based medicine (EBM) into clinical practice requires clinicians to learn to efficiently gain access to clinical evidence and effectively appraise its validity. Even using current electronic systems, selecting literature-based data to solve a single patient-related problem can require more time than practicing physicians or residents can spare. Clinical librarians, as informationists, are uniquely suited to assist physicians in this endeavor. RESULTS: To improve support for evidence-based practice, we have developed a web-based EBM library consult service application (LCS). Librarians use the LCS system to provide full text evidence-based literature with critical appraisal in response to a clinical question asked by a remote physician. LCS uses an entirely Free/Open Source Software platform and will be released under a Free Software license. In the first year of the LCS project, the software was successfully developed and a reference implementation put into active use. Two years of evaluation of the clinical, educational, and attitudinal impact on physician-users and librarian staff are underway, and expected to lead to refinement and wide dissemination of the system. CONCLUSION: A web-based EBM library consult model may provide a useful way for informationists to assist clinicians, and is feasible to implement