8,390 research outputs found

    Microstrip filters for measurement and control of superconducting qubits

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    Careful filtering is necessary for observations of quantum phenomena in superconducting circuits at low temperatures. Measurements of coherence between quantum states requires extensive filtering to protect against noise coupled from room temperature electronics. We demonstrate distributed transmission line filters which cut off exponentially at GHz frequencies and can be anchored at the base temperature of a dilution refrigerator. The compact design makes them suitable to filter many different bias lines in the same setup, necessary for the control and measurement of superconducting qubits

    EPR of Cu\u3csup\u3e2+\u3c/sup\u3e Prion Protein Constructs at 2 GHz Using the \u3cem\u3eg\u3c/em\u3e\u3csub\u3e⊥\u3c/sub\u3e Region to Characterize Nitrogen Ligation

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    A double octarepeat prion protein construct, which has two histidines, mixed with copper sulfate in a 3:2 molar ratio provides at most three imidazole ligands to each copper ion to form a square-planar Cu2+ complex. This work is concerned with identification of the fourth ligand. A new (to our knowledge) electron paramagnetic resonance method based on analysis of the intense features of the electron paramagnetic resonance spectrum in the g⊥ region at 2 GHz is introduced to distinguish between three and four nitrogen ligands. The methodology was established by studies of a model system consisting of histidine imidazole ligation to Cu2+. In this spectral region at 2 GHz (S-band), g-strain and broadening from the possible rhombic character of the Zeeman interaction are small. The most intense line is identified with the MI = +1/2 extra absorption peak. Spectral simulation demonstrated that this peak is insensitive to cupric Ax and Ay hyperfine interaction. The spectral region to the high-field side of this peak is uncluttered and suitable for analysis of nitrogen superhyperfine couplings to determine the number of nitrogens. The spectral region to the low-field side of the intense extra absorption peak in the g⊥ part of the spectrum is sensitive to the rhombic distortion parameters Ax and Ay. Application of the method to the prion protein system indicates that two species are present and that the dominant species contains four nitrogen ligands. A new loop-gap microwave resonator is described that contains ∼1 mL of frozen sample

    Radiotherapy students' perceptions of support provided by clinical supervisors

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    Aim: The aim of this study was to explore the experiences of radiotherapy students on clinical placement, specifically focussing on the provision of well-being support from clinical supervisors. Materials and methods: Twenty-five students from the University of the West of England and City University of London completed an online evaluation survey relating to their experiences of placement, involving Likert scales and open-ended questions. Results: The quantitative results were generally positive; however, the qualitative findings were mixed. Three themes emerged: (1) provision of information and advice; (2) an open, inclusive and supportive working environment; and (3) a lack of communication, understanding, and consistency. Findings: Students' experiences on placement differed greatly and appeared to relate to their specific interactions with different members of staff. It is suggested that additional training around providing well-being support to students may be of benefit to clinical supervisors

    Laboratory based experiments to assess the use of green and food based compost to improve water quality in a Sustainable Drainage (SUDS) device such as a swale

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    Many tonnes of compost are generated per year due to door step composting of both garden and kitchen waste. Whilst there are commercial outlets for the finer grade of compost (< 10 mm) in plant nurseries, there is little demand for the coarser material (> 25 mm). This paper reports part of a WRAP-sponsored (Waste Resources Action Programme) study which investigated the potential for green (GC) and mixed green and food (MC) composts to be incorporated into Sustainable Drainage (SUDS) devices such as swales, and replace the topsoil (TS) onto which turf is laid or grass seed distributed. However, it is not known whether compost can replace TS in terms of pollutant remediation, both the trapping of polluted particulates and in dealing with hydrocarbons such as oil, but also from a biofilm development and activity perspective. Using laboratory based experiments utilising leaching columns and an investigation of microbiological development in the composts studied, it was found that many of the differences in performance between MC and GC were insignificant, whilst both composts performed better in terms of pollutant retention than TS. Mixed compost in particular could be used in devices where there may be oil spillages, such as the lorry park of a Motorway Service Area due to its efficiency in degrading oil. Samples of GC and MC were found to contain many of the bacteria and fungi necessary for an active and efficient biofilm which would be an argument in their favour for replacement of TS and incorporation in swales

    Multiparticle entanglement with quantum logic networks: Application to cold trapped ions

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    We show how to construct a multi-qubit control gate on a quantum register of an arbitrary size N. This gate performs a single-qubit operation on a specific qubit conditioned by the state of other N-1 qubits. We provide an algorithm how to build up an array of networks consisting of single-qubit rotations and multi-qubit control-NOT gates for the synthesis of an arbitrary entangled quantum state of N qubits. We illustrate the algorithm on a system of cold trapped ions. This example illuminates the efficiency of the direct implementation of the multi-qubit CNOT gate compared to its decomposition into a network of two-qubit CNOT gates.Comment: 13 pages, Revtex4, 10 eps figures, 2 tables, to appear in Phys. Rev.

    Patient-reported outcomes and their predictors at 2- and 3-year follow-up after immediate latissimus dorsi breast reconstruction and adjuvant treatment

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    BackgroundThe aim of this study was to estimate the impact 2 and 3 years after surgery of implant‐assisted latissimus dorsi (LDI) and autologous latissimus dorsi (ALD) flap breast reconstructions on patient‐reported outcomes (PROs), and, secondarily, to determine whether baseline characteristics can predict PROs.MethodsThis was a multicentre prospective cohort study. The European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Core Questionnaire (QLQ‐C30) and breast cancer module (QLQ‐BR23), Functional Assessment of Cancer Therapy – Breast (FACT‐B), and Hospital Anxiety and Depression Scale (HADS) PROs were completed before surgery and at 2 and 3 years after breast reconstruction. The effects of LDI and ALD, adjusted for baseline clinicodemographic characteristics, were estimated with multiple linear regressions. Effect sizes above 0·5 were considered clinically important.ResultsSome 206 patients (LDI 93, ALD 113) were recruited in 2007–2013; 66·5 per cent were node‐negative and 34·6 per cent received radiotherapy. Women with adverse clinicopathological factors were more likely to have received radiotherapy and to undergo ALD. Patients in both surgical groups showed clinically important effects at 2 and 3 years, including improvements in emotional scales, but worse physical functioning, social well‐being, body image and anxiety. Radiotherapy adversely affected social functioning at 2 years (P = 0·002). Women undergoing ALD reconstruction had significantly improved sexual functioning at 3 years (P = 0·003) relative to those who had LDI procedures, even after adjusting for case mix (P = 0·007). At 3 years, younger women experienced worse physical well‐being than older women (P = 0·006), and chemotherapy was associated with worse arm symptoms (P = 0·005).ConclusionClinically important changes occurred in physical functioning, breast symptoms, body image and psychological distress. These results will guide selections of key PRO domains and sample‐size calculation of future studies

    Test for entanglement using physically observable witness operators and positive maps

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    Motivated by the Peres-Horodecki criterion and the realignment criterion we develop a more powerful method to identify entangled states for any bipartite system through a universal construction of the witness operator. The method also gives a new family of positive but non-completely positive maps of arbitrary high dimensions which provide a much better test than the witness operators themselves. Moreover, we find there are two types of positive maps that can detect 2xN and 4xN bound entangled states. Since entanglement witnesses are physical observables and may be measured locally our construction could be of great significance for future experiments.Comment: 6 pages, 1 figure, revtex4 styl
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