64,008 research outputs found
Contextuality and Nonlocality in Decaying Multipartite Systems
Everyday experience supports the existence of physical properties independent
of observation in strong contrast to the predictions of quantum theory. In
particular, existence of physical properties that are independent of the
measurement context is prohibited for certain quantum systems. This property is
known as contextuality. This paper studies whether the process of decay in
space-time generally destroys the ability of revealing contextuality. We find
that in the most general situation the decay property does not diminish this
ability. However, applying certain constraints due to the space-time structure
either on the time evolution of the decaying system or on the measurement
procedure, the criteria revealing contextuality become inherently dependent on
the decay property or an impossibility. In particular, we derive how the
context-revealing setup known as Bell's nonlocality tests changes for decaying
quantum systems. Our findings illustrate the interdependence between hidden and
local hidden parameter theories and the role of time.Comment: 5 pages, 2 figure
Are Consumers Fooled by Discounts? An Experimental Test in a Consumer Search Environment
In this paper we investigate experimentally if people search optimally and how price promotions influence search behavior. We implement a sequential search task with exogenous price dispersion in a baseline treatment and introduce discounts in two experimental treatments. We find that search behavior is roughly consistent with optimal search but also observe some discount biases. If subjects don't know in advance where discounts are offered the purchase probability is increased by 19 percentage points in shops with discounts, even after controlling for the benefit of the discount and for risk preferences. If consumers know in advance where discounts are given then the bias is only weakly significant and much smaller (7 percentage points).Consumer Search Theory, Search Cost, Price Promotion
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Does eye examination order for standard automated perimetry matter?
PURPOSE: In spite of faster examination procedures, visual field (VF) results are potentially influenced by fatigue. We use large-scale VF data collected from clinics to test the hypothesis that perimetric fatigue effects are greater in the eye examined second. METHODS: Series of six Humphrey Swedish Interactive Testing Algorithm (SITA) VFs from 6901 patients were retrospectively extracted from a VF database from four different glaucoma clinics. Mean deviation (MD) was compared between first and second tested eyes. A surrogate measure of longitudinal MD variability over time was estimated from errors using linear regression of MD against time then compared between first and second tested eye. RESULTS: Right eye VF was tested consistently first throughout in 6320 (91.6%) patients. Median (interquartile range; IQR) MD in the first tested (right) eye and second tested (left) eye was -2.57 (-6.15, -0.58) dB and -2.70 (-6.34, -0.80) dB respectively (median reduction VF sensitivity of 0.13 dB; p < 0.001). Median (IQR) increase in our surrogate measure of longitudinal MD variability in the second eye tested was 3% (-43%, 50%); this effect was not associated with patient age or rest time between examinations. CONCLUSION: Statistically significant perimetric fatigue effects manifest on average in the second eye tested in routine clinics using Humphrey Field Analyzer SITA examinations. However, the average effects were very small and there was enormous variation among patients. We recommend starting with a right eye examination so that any perimetric fatigue effects, if they exist in an individual, will be as constant as possible from visit to visit
Time reversal Aharonov-Casher effect in mesoscopic rings with Rashba spin-orbital interaction
The time reversal Aharonov-Casher (AC) interference effect in the mesoscopic
ring structures, based on the experiment in Phys. Rev. Lett. \textbf{97},
196803 (2006), is studied theoretically. The transmission curves are calculated
from the scattering matrix formalism, and the time reversal AC interference
frequency is singled out from the Fourier spectra in numerical simulations.
This frequency is in good agreement with analytical result. It is also shown
that in the absent of magnetic field, the Altshuler-Aronov-Spivak type (time
reversal) AC interference retains under the influence of strong disorder, while
the Aharonov-Bohm type AC interference is suppressed.Comment: 5 pages, 4 figures, accepted by Phys. Rev.
Editorial: advances in understanding marine heatwaves and their impacts
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Benthuysen, J. A., Oliver, E. C. J., Chen, K., & Wernberg, T. Editorial: advances in understanding marine heatwaves and their impacts. Frontiers in Marine Science, 7, (2020): 147, doi:10.3389/fmars.2020.00147.Editorial on the Research Topic
Advances in Understanding Marine Heatwaves and Their Impacts
In recent years, prolonged, extremely warm water events, known as marine heatwaves, have featured prominently around the globe with their disruptive consequences for marine ecosystems. Over the past decade, marine heatwaves have occurred from the open ocean to marginal seas and coastal regions, including the unprecedented 2011 Western Australia marine heatwave (Ningaloo Niño) in the eastern Indian Ocean (e.g., Pearce et al., 2011), the 2012 northwest Atlantic marine heatwave (Chen et al., 2014), the 2012 and 2015 Mediterranean Sea marine heatwaves (Darmaraki et al., 2019), the 2013/14 western South Atlantic (Rodrigues et al., 2019) and 2017 southwestern Atlantic marine heatwave (Manta et al., 2018), the persistent 2014–2016 “Blob” in the North Pacific (Bond et al., 2015; Di Lorenzo and Mantua, 2016), the 2015/16 marine heatwave spanning the southeastern tropical Indian Ocean to the Coral Sea (Benthuysen et al., 2018), and the Tasman Sea marine heatwaves in 2015/16 (Oliver et al., 2017) and 2017/18 (Salinger et al., 2019). These events have set new records for marine heatwave intensity, the temperature anomaly exceeding a climatology, and duration, the sustained period of extreme temperatures. We have witnessed the profound consequences of these thermal disturbances from acute changes to marine life to enduring impacts on species, populations, and communities (Smale et al., 2019).
These marine heatwaves have spurred a diversity of research spanning the methodology of identifying and quantifying the events (e.g., Hobday et al., 2016) and their historical trends (Oliver et al., 2018), understanding their physical mechanisms and relationships with climate modes (e.g., Holbrook et al., 2019), climate projections (Frölicher et al., 2018), and understanding the biological impacts for organisms and ecosystem function and services (e.g., Smale et al., 2019). By using sea surface temperature percentiles, temperature anomalies can be quantified based on their local variability and account for the broad range of temperature regimes in different marine environments. For temperatures exceeding a 90th-percentile threshold beyond a period of 5-days, marine heatwaves can be classified into categories based on their intensity (Hobday et al., 2018). While these recent advances have provided the framework for understanding key aspects of marine heatwaves, a challenge lies ahead for effective integration of physical and biological knowledge for prediction of marine heatwaves and their ecological impacts.
This Research Topic is motivated by the need to understand the mechanisms for how marine heatwaves develop and the biological responses to thermal stress events. This Research Topic is a collection of 18 research articles and three review articles aimed at advancing our knowledge of marine heatwaves within four themes. These themes include methods for detecting marine heatwaves, understanding their physical mechanisms, seasonal forecasting and climate projections, and ecological impacts.We thank the contributing authors, reviewers, and the editorial staff at Frontiers in Marine Science for their support in producing this issue. We thank the Marine Heatwaves Working Group (http://www.marineheatwaves.org/) for inspiration and discussions. This special issue stemmed from the session on Advances in Understanding Marine Heat Waves and Their Impacts at the 2018 Ocean Sciences meeting (Portland, USA)
Research on Optimized Problem-solving Solutions: Selection of the Production Process
In manufacturing industries, various problems may occur during the production process. The problems are complexand involve the relevant context of working environments. A problem-solving process is often initiated to create asolution and achieve a desired status. In this process, determining how to obtain a solution from the variouscandidate solutions is an important issue. In such uncertain working environments, context information can providerich clues for problem-solving decision making. This work uses a selection approach to determine an optimizedproblem-solving process which will assist workers in choosing reasonable solutions. A context-based utility modelexplores the problem context information to obtain candidate solution actual utility values; a multi-criteria decisionanalysis uses the actual utility values to determine the optimal selection order for candidate solutions. Theselection order is presented to the worker as an adaptive knowledge recommendation. The worker chooses areasonable problem-solving solution based on the selection order. This paper uses a high-tech company’sknowledge base log as a source of analysis data. The experimental results show that the chosen approach to anoptimized problem-solving solution selection is effective. The contribution of this research is a method which iseasy to implement in a problem-solving decision support system
Oxygen-vacancy-mediated Negative Differential Resistance in La and Mg co-substituted BiFeO3 Thin Film
The conductive characteristics of Bi0.9La0.1Fe0.96Mg0.04O3(BLFM) thin film
are investigated at various temperatures and a negative differential resistance
(NDR) is observed in the thin film, where a leakage current peak occurs upon
application of a downward electric field above 80 oC. The origin of the NDR
behavior is shown to be related to the ionic defect of oxygen vacancies (VO..)
present in the film. On the basis of analyzing the leakage mechanism and
surface potential behavior, the NDR behavior can be understood by considering
the competition between the polarized distribution and neutralization of VO..
Multidimensional optical fractionation with holographic verification
The trajectories of colloidal particles driven through a periodic potential
energy landscape can become kinetically locked in to directions dictated by the
landscape's symmetries. When the landscape is realized with forces exerted by a
structured light field, the path a given particle follows has been predicted to
depend exquisitely sensitively on such properties as the particle's size and
refractive index These predictions, however, have not been tested
experimentally. Here, we describe measurements of colloidal silica spheres'
transport through arrays of holographic optical traps that use holographic
video microscopy to track individual spheres' motions in three dimensions and
simultaneously to measure each sphere's radius and refractive index with
part-per-thousand resolution. These measurements confirm previously untested
predictions for the threshold of kinetically locked-in transport, and
demonstrate the ability of optical fractionation to sort colloidal spheres with
part-per-thousand resolution on multiple characteristics simultaneously.Comment: 4 pages, 2 figures. Accepted for publication in Physical Review
Letter
The private capacity of quantum channels is not additive
Recently there has been considerable activity on the subject of additivity of
various quantum channel capacities. Here, we construct a family of channels
with sharply bounded classical, hence private capacity. On the other hand,
their quantum capacity when combined with a zero private (and zero quantum)
capacity erasure channel, becomes larger than the previous classical capacity.
As a consequence, we can conclude for the first time that the classical
private capacity is non-additive. In fact, in our construction even the quantum
capacity of the tensor product of two channels can be greater than the sum of
their individual classical private capacities.
We show that this violation occurs quite generically: every channel can be
embedded into our construction, and a violation occurs whenever the given
channel has larger entanglement assisted quantum capacity than (unassisted)
classical capacity.Comment: 4+4 pages, 2 eps figures. V2 has title and abstract changed; its new
structure reflects the final version of a main paper plus appendices
containing mathematical detail
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