| 1. |
- Abdellaoui, G., et al.
(författare)
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First observations of speed of light tracks by a fluorescence detector looking down on the atmosphere
- 2018
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Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- EUSO-Balloon is a pathfinder mission for the Extreme Universe Space Observatory onboard the Japanese Experiment Module (JEM-EUSO). It was launched on the moonless night of the 25(th) of August 2014 from Timmins, Canada. The flight ended successfully after maintaining the target altitude of 38 km for five hours. One part of the mission was a 2.5 hour underflight using a helicopter equipped with three UV light sources (LED, xenon flasher and laser) to perform an inflight calibration and examine the detectors capability to measure tracks moving at the speed of light. We describe the helicopter laser system and details of the underflight as well as how the laser tracks were recorded and found in the data. These are the first recorded laser tracks measured from a fluorescence detector looking down on the atmosphere. Finally, we present a first reconstruction of the direction of the laser tracks relative to the detector.
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| 3. |
- Chakarova, Roumiana, et al.
(författare)
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An automated Monte Carlo QC system for volumetric modulated arc therapy: Possibilities and challenges
- 2018
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Ingår i: Physica Medica-European Journal of Medical Physics. - : Elsevier BV. - 1120-1797. ; 51, s. 32-37
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To develop and implement an automated Monte Carlo (MC) system for patient specific VMAT quality control in a patient geometry that generates treatment planning system (TPS) compliant DICOM objects and includes a module for 3D analysis of dose deviations. Also, the aims were to recommend diagnose specific tolerance criteria and an evaluation procedure. Methods: The EGSnrc code package formed the basis for development of the MC system. The workflow consists of a number of modules connected to a TPS by means of manual DICOM exports and imports which were executed sequentially without user interaction. DVH comparison was performed in the TPS. In addition, MC-and TPS dose distributions were analysed by applying the normalized dose difference (NDD) formalism. NDD failure maps and a pass rate for a certain threshold were obtained. 170 clinical plans (prostate, thorax, head-and-neck and gynecological) were selected for analysis. Results: Agreement within 1.5% was found between clinical-and MC data for the mean dose to the target volumes and within 3% for parameters more sensitive to the shape of the DVH e.g. D-98% PTV. Regarding the NDD analysis, tolerance criteria 2%/3 mm were established for prostate plans and 3%/3 mm for the rest of the cases. Conclusions: An automated MC system was developed and implemented. Evaluation procedure is recommended with NDD-analysis as a first step. For pass rate < 95%, the evaluation continues with comparison of DVH parameters. For deviations larger than 2%, a visual inspection of the clinical-and MC dose distributions is performed.
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| 4. |
- Hitimana, Regis, et al.
(författare)
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Health related quality of life determinants for Rwandan women after delivery
- 2017
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Ingår i: European Journal of Public Health. - : OXFORD UNIV PRESS. - 1101-1262 .- 1464-360X. ; 27:Suppl_3, s. 436-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Health related quality of life determinants for Rwandan women after delivery. Does Antenatal care utilization matter? Maternal health conditions are still a major problem in most low-income countries. The postpartum health status and the effect of antenatal care utilization on health are relatively under researched. This study aims at (1) assessing whether receipt of antenatal care according to Rwandan guidelines is associated with mother’s health-related quality of life (HRQoL) and (2) exploring determinants associated with mother’s HRQoL in the first year (1-13 months) after delivery in Rwanda. In 2014 a cross-sectional survey was conducted on 922 women from Kigali City and Northern province of Rwanda, who gave birth in the period of 1–13 months prior to survey. The study population was randomly selected and interviewed using a questionnaire. HRQoL was measured using EQ-5D-3L. Average values of HRQoL were computed by demographic and socio-economic characteristics. The effect of adequate antenatal care on HRQoL was tested in two multivariable linear regression models - with EQ-5D weights and the Visual Analogue Scale score as outcomes respectively - with ANC adequacy and socio-demographic and psychosocial variables as predictors. Mean HRQoL was 0.92 using EQ-5D and 69.58 using EQ-VAS. Fifteen per cent reported moderate pain/discomfort and 1% reported extreme pain/discomfort, 16% reported being moderately anxious/depressed and 3% reported being extremely anxious/depressed. Having more than one child and being cohabitant or single/not married was associated with significantly lower HRQoL, while having good social support and belonging to the highest wealth quintile was associated with higher HRQoL. Antenatal care utilization was not associated with HRQoL among postpartum mothers. Policy makers should address the social determinants of health, and promote social networks among women. There is a need to assess the quality of Antenatal care in Rwanda.Key messages:Health related quality of life among postpartum mothers is high. Pain or discomfort and anxiety of depression are most prevalent problems.Antenatal care utilization was not associated with HRQoL among postpartum mothers. Rather social determinants of health are important in determining mother's HRQoL
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| 5. |
- Krantz, Philip, 1984, et al.
(författare)
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A quantum engineer's guide to superconducting qubits
- 2019
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Ingår i: Applied Physics Reviews. - : AIP Publishing. - 1931-9401. ; 6:2
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this review is to provide quantum engineers with an introductory guide to the central concepts and challenges in the rapidly accelerating field of superconducting quantum circuits. Over the past twenty years, the field has matured from a predominantly basic research endeavor to a one that increasingly explores the engineering of larger-scale superconducting quantum systems. Here, we review several foundational elements-qubit design, noise properties, qubit control, and readout techniques-developed during this period, bridging fundamental concepts in circuit quantum electrodynamics and contemporary, state-of-The-Art applications in gate-model quantum computation.
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| 8. |
- Yan, Fei, et al.
(författare)
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Distinguishing coherent and thermal photon noise in a circuit quantum electrodynamical system
- 2018
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 120:26
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Tidskriftsartikel (refereegranskat)abstract
- In the cavity-QED architecture, photon number fluctuations from residual cavity photons cause qubit dephasing due to the ac Stark effect. These unwanted photons originate from a variety of sources, such as thermal radiation, leftover measurement photons, and cross talk. Using a capacitively shunted flux qubit coupled to a transmission line cavity, we demonstrate a method that identifies and distinguishes coherent and thermal photons based on noise-spectral reconstruction from time-domain spin-locking relaxometry. Using these measurements, we attribute the limiting dephasing source in our system to thermal photons rather than coherent photons. By improving the cryogenic attenuation on lines leading to the cavity, we successfully suppress residual thermal photons and achieve T1-limited spin-echo decay time. The spin-locking noise-spectroscopy technique allows broad frequency access and readily applies to other qubit modalities for identifying general asymmetric nonclassical noise spectra.
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| 9. |
- Yan, Fei, et al.
(författare)
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Tunable Coupling Scheme for Implementing High-Fidelity Two-Qubit Gates
- 2018
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Ingår i: Physical Review Applied. - 2331-7019. ; 10:5
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Tidskriftsartikel (refereegranskat)abstract
- The prospect of computational hardware with quantum advantage relies critically on the quality of quantum-gate operations. Imperfect two-qubit gates are a major bottleneck for achieving scalable quantum-information processors. Here, we propose a generalizable and extensible scheme for a two-qubit tunable coupler that controls the qubit-qubit coupling by modulating the coupler frequency. Two-qubit gate operations can be implemented by operating the coupler in the dispersive regime, which is noninvasive to the qubit states. We investigate the performance of the scheme by simulating a universal two-qubit gate on a superconducting quantum circuit, and find that errors from known parasitic effects are strongly suppressed. The scheme is compatible with existing high-coherence hardware, thereby promising a higher gate fidelity with current technologies.
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