471 research outputs found

    Multi-order interference is generally nonzero

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    It is demonstrated that the third-order interference, as obtained from explicit solutions of Maxwell's equations for realistic models of three-slit devices, including an idealized version of the three-slit device used in a recent three-slit experiment with light (U. Sinha et al., Science 329, 418 (2010)), is generally nonzero. The hypothesis that the third-order interference should be zero is shown to be fatally flawed because it requires dropping the one-to-one correspondence between the symbols in the mathematical theory and the different experimental configurations.Comment: Replaced Figs. 4,5 and caption of Fig.

    Impact of minority concentration on fundamental (H)D ICRF heating performance in JET-ILW

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    ITER will start its operation with non-activated hydrogen and helium plasmas at a reduced magnetic field of B-0 = 2.65 T. In hydrogen plasmas, the two ion cyclotron resonance frequency (ICRF) heating schemes available for central plasma heating (fundamental H majority and 2nd harmonic He-3 minority ICRF heating) are likely to suffer from relatively low RF wave absorption, as suggested by numerical modelling and confirmed by previous JET experiments conducted in conditions similar to those expected in ITER's initial phase. With He-4 plasmas, the commonly adopted fundamental H minority heating scheme will be used and its performance is expected to be much better. However, one important question that remains to be answered is whether increased levels of hydrogen (due to e. g. H pellet injection) jeopardize the high performance usually observed with this heating scheme, in particular in a full-metal environment. Recent JET experiments performed with the ITER-likewall shed some light onto this question and the main results concerning ICRF heating performance in L-mode discharges are summarized here

    Fundamental cyclotron 3He minority ICRF heating experiments in H plasmas in JET in presence of the ILW

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    Efficient plasma heating schemes are a prerequisite for reaching fusion relevant temperatures in fusion machines. On the road to reaching ignition, non-activated scenarios - such as (3He

    Effect of toroidal field ripple on plasma rotation in JET

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    Dedicated experiments on TF ripple effects on the performance of tokamak plasmas have been carried out at JET. The TF ripple was found to have a profound effect on the plasma rotation. The central Mach number, M, defined as the ratio of the rotation velocity and the thermal velocity, was found to drop as a function of TF ripple amplitude (3) from an average value of M = 0.40-0.55 for operations at the standard JET ripple of 6 = 0.08% to M = 0.25-0.40 for 6 = 0.5% and M = 0.1-0.3 for delta = 1%. TF ripple effects should be considered when estimating the plasma rotation in ITER. With standard co-current injection of neutral beam injection (NBI), plasmas were found to rotate in the co-current direction. However, for higher TF ripple amplitudes (delta similar to 1%) an area of counter rotation developed at the edge of the plasma, while the core kept its co-rotation. The edge counter rotation was found to depend, besides on the TF ripple amplitude, on the edge temperature. The observed reduction of toroidal plasma rotation with increasing TF ripple could partly be explained by TF ripple induced losses of energetic ions, injected by NBI. However, the calculated torque due to these losses was insufficient to explain the observed counter rotation and its scaling with edge parameters. It is suggested that additional TF ripple induced losses of thermal ions contribute to this effect

    Corpuscular Event-by-Event Simulation of Quantum Optics Experiments: Application to a Quantum-Controlled Delayed-Choice Experiment

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    A corpuscular simulation model of optical phenomena that does not require the knowledge of the solution of a wave equation of the whole system and reproduces the results of Maxwell's theory by generating detection events one-by-one is discussed. The event-based corpuscular model gives a unified description of multiple-beam fringes of a plane parallel plate and single-photon Mach-Zehnder interferometer, Wheeler's delayed choice, photon tunneling, quantum eraser, two-beam interference, Einstein-Podolsky-Rosen-Bohm and Hanbury Brown-Twiss experiments. The approach is illustrated by application to a recent proposal for a quantum-controlled delayed choice experiment, demonstrating that also this thought experiment can be understood in terms of particle processes only.Comment: Invited paper presented at FQMT11. Accepted for publication in Physica Scripta 27 June 201

    N=2 ICRH of H majority plasmas in JET-ILW

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    Heating single ion species plasmas with ICRF is a challenging task: Fundamental ion cyclotron heating (w = w(ci)) suffers from the adverse polarization of the RF electric fields near the majority cyclotron resonance while second harmonic heating (w =2w(ci)) typically requires pre-heating of the plasma ions to become efficient. Recently, w =2wci ICRF heating was tested in JET-ILW hydrogen plasmas in the absence of neutral beam injection (L-mode). Despite the lack of pre-heating, up to 6MW of ICRF power were coupled to the plasma leading to a transition to H-mode for P-ICRH>5MW in most discharges. Heating efficiencies between 0.65-0.85 were achieved as a combination of the low magnetic field adopted (enhanced finite Larmor radius effects) and the deliberate slow rise of the ICRF power, allowing time for a fast ion population to gradually build-up leading to a systematic increase of the wave absorptivity. Although fast ion tails are a common feature of harmonic ICRF heating, the N=2 majority heating features moderate tail energies (<500keV) except at very low plasma densities (n(e0)<3x10(19)/m(3)), where fast H tails in the MeV range developed and fast ion losses became significant, leading to enhanced plasma wall interaction. The main results of these experiments will be reported

    Type of treatment, symptoms and patient satisfaction play an important role in primary care contact during prostate cancer follow-up:Results from the population-based PROFILES registry

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    BACKGROUND: With the increasing attention for the role of General Practitioners (GPs) after cancer treatment, it is important to better understand the involvement of GPs following prostate cancer treatment. This study investigates factors associated with GP contact during follow-up of prostate cancer survivors, such as patient, treatment and symptom variables, and satisfaction with, trust in, and appraised knowledge of GPs. METHODS: Of 787 prostate cancer survivors diagnosed between 2007 and 2013, and selected from the Netherlands Cancer Registry, 557 (71%) responded to the invitation to complete a questionnaire. Multivariable logistic regression analyses were performed to investigate which variables were associated with GP contact during follow- up. RESULTS: In total, 200 (42%) prostate cancer survivors had contact with their GP during follow-up, and 76 (16%) survivors preferred more contact. Survivors who had an intermediate versus low educational level (OR = 2.0) were more likely to have had contact with their GP during follow-up. Survivors treated with surgery (OR = 2.8) or hormonal therapy (OR = 3.5) were also more likely to seek follow-up care from their GP compared to survivors who were treated with active surveillance. Patient reported bowel symptoms (OR = 1.4), hormonal symptoms (OR = 1.4), use of incontinence aids (OR = 1.6), and being satisfied with their GP (OR = 9.5) were also significantly associated with GP contact during follow-up. CONCLUSIONS: Education, treatment, symptoms and patient satisfaction were associated with GP contact during prostate cancer follow-up. These findings highlight the potential for adverse side-effects to be managed in primary care. In light of future changes in cancer care, evaluating prostate cancer follow-up in primary care remains important

    Integration of Placental Transfer in a Fetal–Maternal Physiologically Based Pharmacokinetic Model to Characterize Acetaminophen Exposure and Metabolic Clearance in the Fetus

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    Background and Objective: Although acetaminophen is frequently used during pregnancy, little is known about fetal acetaminophen pharmacokinetics. Acetaminophen safety evaluation has typically focused on hepatotoxicity, while other events (fetal ductal closure/constriction) are also relevant. We aimed to develop a fetal–maternal physiologically based pharmacokinetic (PBPK) model (f-m PBPK) to quantitatively predict placental acetaminophen transfer, characterize fetal acetaminophen exposure, and quantify the contributions of specific clearance pathways in the term fetus. Methods: An acetaminophen pregnancy PBPK model was extended with a compartment representing the fetal liver, which included maturation of relevant enzymes. Different approaches to describe placental transfer were evaluated (ex vivo cotyledon perfusion experiments, placental transfer prediction based on Caco-2 cell permeability or physicochemical properties [MoBi®]). Predicted maternal and fetal acetaminophen profiles were compared with in vivo observations. Results: Tested approaches to predict placental t
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