1,418 research outputs found
Brief Mindfulness Meditation Improves Attention In Novices: Evidence From ERPs And Moderation By Neuroticism
Past research has found that mindfulness meditation training improves executive attention. Event-related potentials (ERPs) have indicated that this effect could be driven by more efficient allocation of resources on demanding attentional tasks, such as the Flanker Task and the Attention Network Test (ANT). However, it is not clear whether these changes depend on long-term practice. In two studies, we sought to investigate the effects of a brief, 10-min meditation session on attention in novice meditators, compared to a control activity. We also tested moderation by individual differences in neuroticism and the possible underlying neural mechanisms driving these effects, using ERPs. In Study 1, participants randomly assigned to listen to a 10-min meditation tape had better accuracy on incongruent trials on a Flanker task, with no detriment in reaction times (RTs), indicating better allocation of resources. In Study 2, those assigned to listen to a meditation tape performed an ANT more quickly than control participants, with no detriment in performance. Neuroticism moderated both of these effects, and ERPs showed that those individuals lower in neuroticism who meditated for 10 min exhibited a larger N2 to incongruent trials compared to those who listened to a control tape; whereas those individuals higher in neuroticism did not. Together, our results support the hypothesis that even brief meditation improves allocation of attentional resources in some novices
Impulsive noise removal from color images with morphological filtering
This paper deals with impulse noise removal from color images. The proposed
noise removal algorithm employs a novel approach with morphological filtering
for color image denoising; that is, detection of corrupted pixels and removal
of the detected noise by means of morphological filtering. With the help of
computer simulation we show that the proposed algorithm can effectively remove
impulse noise. The performance of the proposed algorithm is compared in terms
of image restoration metrics and processing speed with that of common
successful algorithms.Comment: The 6th international conference on analysis of images, social
networks, and texts (AIST 2017), 27-29 July, 2017, Moscow, Russi
Texture and shape of two-dimensional domains of nematic liquid crystal
We present a generalized approach to compute the shape and internal structure
of two-dimensional nematic domains. By using conformal mappings, we are able to
compute the director field for a given domain shape that we choose from a rich
class, which includes drops with large and small aspect ratios, and sharp
domain tips as well as smooth ones. Results are assembled in a phase diagram
that for given domain size, surface tension, anchoring strength, and elastic
constant shows the transitions from a homogeneous to a bipolar director field,
from circular to elongated droplets, and from sharp to smooth domain tips. We
find a previously unaccounted regime, where the drop is nearly circular, the
director field bipolar and the tip rounded. We also find that bicircular
director fields, with foci that lie outside the domain, provide a remarkably
accurate description of the optimal director field for a large range of values
of the various shape parameters.Comment: 12 pages, 10 figure
Geometry-dependent critical currents in superconducting nanocircuits
In this paper we calculate the critical currents in thin superconducting
strips with sharp right-angle turns, 180-degree turnarounds, and more
complicated geometries, where all the line widths are much smaller than the
Pearl length . We define the critical current as the
current that reduces the Gibbs free-energy barrier to zero. We show that
current crowding, which occurs whenever the current rounds a sharp turn, tends
to reduce the critical current, but we also show that when the radius of
curvature is less than the coherence length this effect is partially
compensated by a radius-of-curvature effect. We propose several patterns with
rounded corners to avoid critical-current reduction due to current crowding.
These results are relevant to superconducting nanowire single-photon detectors,
where they suggest a means of improving the bias conditions and reducing dark
counts. These results also have relevance to normal-metal nanocircuits, as
these patterns can reduce the electrical resistance, electromigration, and hot
spots caused by nonuniform heating.Comment: 29 pages, 24 figure
Targeting Inaccurate Atomic Data in the Eta Car Ejecta Absorption
The input from the laboratory spectroscopist community has on many occasions helped the analysis of the eta Car spectrum. Our analysis has targeted spectra where improved wavelengths and oscillator strengths are needed. We will demonstrate how experimentally derived atomic data have improved our spectral analysis, and illuminate where more work still is needed
3D mappings by generalized joukowski transformations
The classical Joukowski transformation plays an important role in di erent applications of conformal mappings,
in particular in the study of
ows around the so-called Joukowski airfoils. In the 1980s H. Haruki and M.
Barran studied generalized Joukowski transformations of higher order in the complex plane from the view point
of functional equations. The aim of our contribution is to study the analogue of those generalized Joukowski
transformations in Euclidean spaces of arbitrary higher dimension by methods of hypercomplex analysis. They
reveal new insights in the use of generalized holomorphic functions as tools for quasi-conformal mappings.
The computational experiences focus on 3D-mappings of order 2 and their properties and visualizations for
di erent geometric con gurations, but our approach is not restricted neither with respect to the dimension
nor to the order.Financial support from "Center for Research and Development in Mathematics and Applications" of the University of Aveiro, through the Portuguese Foundation for Science and Technology (FCT), is gratefully acknowledged. The research of the first author was also supported by the FCT under the fellowship SFRH/BD/44999/2008. Moreover, the authors would like to thank the anonymous referees for their helpful comments and suggestions which improved greatly the final manuscript
Representation of Quantum Field Theory by Elementary Quantum Information
In this paper is considered relativistic quantum field theory expressed by
elementary units of quantum information as they are considered as fundamental
entity of nature by Carl Friedrich von Weizsaecker. Through quantization of a
Weyl spinor describing an elementary unit of quantum information and consisting
of four real components one obtains four pairs of creation and annihilation
operators acting in a tensor space of states containing many units of quantum
information. There can be constructed position and momentum operators from the
creation and annihilation operators and based on these operators the Poincare
group can be represented in this abstract tensor space of quantum information.
A general state in the tensor space can be mapped to a state in Minkowski
space-time by using the position representation of the eigenstates of the
occupation number operators which correspond to the eigenstates of the harmonic
oscillator. This yields a description of relativistic quantum mechanics.
Quantization of the coefficients of a general state in the tensor space leads
to many particle theory and thus to quantum field theory.Comment: 7 page
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