Quantum engineering of atomic phase-shifts in optical clocks

Quantum engineering of time-separated Raman laser pulses in three-level systems is presented to produce an ultra-narrow optical transition in bosonic alkali-earth clocks free from light shifts and with a significantly reduced sensitivity to laser parameter fluctuations. Based on a quantum artificial complex-wave-function analytical model, and supported by a full density matrix simulation including a possible residual effect of spontaneous emission from the intermediate state, atomic phase-shifts associated to Ramsey and Hyper-Ramsey two-photon spectroscopy in optical clocks are derived. Various common-mode Raman frequency detunings are found where the frequency shifts from off-resonant states are canceled, while strongly reducing their uncertainties at the 10$^{-18}$ level of accuracy.Comment: accepted for publication in PR

Adaptively time stepping the stochastic Landau-Lifshitz-Gilbert equation at nonzero temperature: implementation and validation in MuMax3

Thermal fluctuations play an increasingly important role in micromagnetic research relevant for various biomedical and other technological applications. Until now, it was deemed necessary to use a time stepping algorithm with a fixed time step in order to perform micromagnetic simulations at nonzero temperatures. However, Berkov and Gorn have shown that the drift term which generally appears when solving stochastic differential equations can only influence the length of the magnetization. This quantity is however fixed in the case of the stochastic Landau-Lifshitz-Gilbert equation. In this paper, we exploit this fact to straightforwardly extend existing high order solvers with an adaptive time stepping algorithm. We implemented the presented methods in the freely available GPU-accelerated micromagnetic software package MuMax3 and used it to extensively validate the presented methods. Next to the advantage of having control over the error tolerance, we report a twenty fold speedup without a loss of accuracy, when using the presented methods as compared to the hereto best practice of using Heun's solver with a small fixed time step.Comment: 9 pages, 9 figure

Investigating nystagmus in patients with traumatic brain injury: A systematic review (1996 - 2016)

Background. Traumatic brain injury (TBI) is a health and socioeconomic concern worldwide. In patients with TBI, post-traumatic balance problems are often the result of damage to the vestibular system. Nystagmus is common in these patients, and can provide insight into the damage that has resulted from the trauma.Objective. To present a systematic overview of published literature regarding nystagmus in patients with TBI.Methods. Nine databases and platforms were searched during October 2016 for articles published between 1996 and 2016. Studies of any research design and published in English that focused on nystagmus in patients with TBI were considered for inclusion. A total of 110 articles were screened once duplicates had been removed, and 29 full-text articles were assessed. Eleven articles were included in the quality appraisal phase (using the McMaster tool), after which 10 articles were included in this review.Results. This review describes nystagmus in 713 patients, and all articles reviewed described the type of assessment method that was used. However, the results lacked comprehensive data regarding the assessment, measurement and description of nystagmus in TBI patients, or the possible link and relationship between nystagmus and TBI.Conclusions. This systematic review indicated that: (i) there is a growing body of evidence that benign paroxysmal positional vertigo should be considered during the medical examination of all patients suffering from head trauma; (ii) all patients with TBI should undergo visual (eye movement) and vestibular examination; and (iii) future studies should include quantitative measurements of eye movements and nystagmus.

Relating spatial pattern of forest cover to accessibility

Urban planning for optimal provision of recreational forests is not only concerned with how much space is needed, but equally with how this could be arranged in the landscape in order to make these forests accessible to many potential visitors. The present study sought to establish relationships between the spatial pattern of forest cover and these forests’ accessibility – either on foot or by bike – for short walks. This question was approached in an experimental way using landscape structure metrics. A factor analysis identified the common axes of spatial pattern. The first five factors explained 82.2% of the variation of the original data set. The first factor is related to forested area and number of forest patches, the second is related to shape complexity. The third factor quantifies contiguity, and the fourth measures the clumpiness of forests. The fifth refers to variability in forest shape. Only the factors related to forested area, forest shape complexity and clumpiness, show a significant correlation with recreational provision. A higher forest coverage and more forests should thus lead to a higher provision for short walking trips. However, when a small afforestation budget is available, high shape complexity, low forest contiguity and a high landscape shape index (LSI) should take priority. Shape indices make the most important contribution to single out patterns that offer recreation possibilities to a high number of people. The findings show the potential of using landscape structure metrics for the modelling of forest recreational provision

Quality evaluation of fresh and bloomed filled chocolates in House of Quality

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