346 research outputs found
Seeing the invisible: The scope and limits of unconscious processing in binocular rivalry
When an image is presented to one eye and a very different image is presented to the corresponding location of the other eye, they compete for conscious representation, such that only one image is visible at a time while the other is suppressed. Called binocular rivalry, this phenomenon and its deviants have been extensively exploited to study the mechanism and neural correlates of consciousness. In this paper, we propose a framework, the unconscious binding hypothesis, to distinguish unconscious processing from conscious processing. According to this framework, the unconscious mind not only encodes individual features but also temporally binds distributed features to give rise to cortical representation, but unlike conscious binding, such unconscious binding is fragile. Under this framework, we review evidence from psychophysical and neuroimaging studies, which suggests that: (1) for invisible low level features, prolonged exposure to visual pattern and simple translational motion can alter the appearance of subsequent visible features (i.e. adaptation); for invisible high level features, although complex spiral motion cannot produce adaptation, nor can objects/words enhance subsequent processing of related stimuli (i.e. priming), images of tools can nevertheless activate the dorsal pathway; and (2) although invisible central cues cannot orient attention, invisible erotic pictures in the periphery can nevertheless guide attention, likely through emotional arousal; reciprocally, the processing of invisible information can be modulated by attention at perceptual and neural levels
The asymmetric effect of plasma response to variation of quasar radiation
Plasma is prevalent throughout the universe. The cosmic plasma serves as not
only a crucial tracer for studying the evolution of the cosmos but also an
ideal laboratory for investigating the properties of plasma in extreme
conditions. As one of the important contributors to the re-ionization of the
universe, the variability in quasar (driven by the supermassive black hole)
radiation presents a convenient opportunity to study the response of gases
ionized by them. Based on extensive statistical analysis using data from the
Sloan Digital Sky Survey (SDSS), it has been demonstrated that the response of
gases to quasar radiation exhibits asymmetry. Specifically, over 70\% of broad
absorption lines (BALs) gas in quasar host galaxies exhibit a negative
response. Through analytical calculations and photoionization simulations of C
IV, we found that the response of gases to radiation is asymmetric for low and
high ionization states. In high ionization states, the response time scale is
shorter, leading to the detection of more negative responses. In actual case,
the observation time interval is mostly greater than 1 day, and hence the
asymmetric effect of the C IV response gives a typical gas density of upper
limit of . Interestingly, this is consistent with the fact
that most of the measured BAL gas densities are below . In
principle, the detection of this asymmetric effect becomes easier with lower
plasma density or shorter observation time intervals.Comment: 7 pages, 5 figures, comments welcom
ORB-SLAM based humanoid robot location and navigation system
Aiming at the indoor location and navigation problem of humanoid biped robot with complex motion structure, a humanoid biped robot localization and navigation system based on ORB-SLAM is designed. Firstly, the working principle of ORB-SLAM is analyzed, and it is improved to realize the function of missing map reading and generating dense point cloud map. Secondly, the dense point cloud map is converted to octomap, and then the conversion of 3D map to 2D map is completed. The SBPL planning library is improved to carry out the path planning of the robot, and the path planning based on the boundary exploration is realized. Finally, the experimental verification is carried out on the biped robot to verify the effectiveness of the location and navigation system design in the indoor environment
Reconstruction-Aware Prior Distillation for Semi-supervised Point Cloud Completion
Point clouds scanned by real-world sensors are always incomplete, irregular,
and noisy, making the point cloud completion task become increasingly more
important. Though many point cloud completion methods have been proposed, most
of them require a large number of paired complete-incomplete point clouds for
training, which is labor exhausted. In contrast, this paper proposes a novel
Reconstruction-Aware Prior Distillation semi-supervised point cloud completion
method named RaPD, which takes advantage of a two-stage training scheme to
reduce the dependence on a large-scale paired dataset. In training stage 1, the
so-called deep semantic prior is learned from both unpaired complete and
unpaired incomplete point clouds using a reconstruction-aware pretraining
process. While in training stage 2, we introduce a semi-supervised prior
distillation process, where an encoder-decoder-based completion network is
trained by distilling the prior into the network utilizing only a small number
of paired training samples. A self-supervised completion module is further
introduced, excavating the value of a large number of unpaired incomplete point
clouds, leading to an increase in the network's performance. Extensive
experiments on several widely used datasets demonstrate that RaPD, the first
semi-supervised point cloud completion method, achieves superior performance to
previous methods on both homologous and heterologous scenarios
Pressure-induced one-dimensional oxygen ion diffusion channel in lead-apatite
Recently, Lee et al. claimed that the experimental observation of
room-temperature ambient-pressure superconductivity in a Cu-doped lead-apatite
(Pb10-xCux(PO4)6O). The study revealed the Cu doping induces a chemical
pressure, resulting in a structural contraction of one-dimensional Cu-O-Cu
atomic column. This unique structure promotes a one-dimensional electronic
conduction channel along the c-axis mediated by the O atoms, which may be
related to superconductivity. These O atoms occupy 1/4 of the equivalent
positions along the c-axis and exhibit a low diffusion activation energy of 0.8
eV, indicating the possibility of diffusion between these equivalent positions.
Here, using machine-learning based deep potential, we predict the
pressure-induced fast diffusion of 1/4-occupied O atoms along the
one-dimensional channel in Pb10(PO4)6O at 500 K, while the frameworks of Pb
triangles and PO4 tetrahedrons remain stable. The calculation results also
indicate Cu doping can provide appropriate effective chemical pressure,
indicating the one-dimensional ion diffusion channel may appear in
Pb9Cu(PO4)6O, even at ambient pressure. Our finding shows that the
one-dimensional ions diffusion channel may be an important factor to affects
the fabrication and electrical measurement of doped lead-apatite.Comment: 15 pages, 7 figure
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