99,039 research outputs found
Synthetic 3D Pap smear nucleus generation
Gómez Aguilar, S. (2010). Synthetic 3D Pap smear nucleus generation. http://hdl.handle.net/10251/10215.Archivo delegad
Raman Spectroscopy Study of alpha-, beta-, gamma-NaxCoO2 and gamma-(Ca,Sr)xCoO2
Raman spectroscopy measurements have been performed on alpha-, beta-,
gamma-NaxCoO2 phases differing in their stacking of CoO6 octahedra along the
c-axis direction. The results demonstrate that, in general, there are five
active phonons for gamma-Na0.75CoO2, two Raman active phonons for alpha-NaCoO2,
and four Raman active phonons for beta-NaCoO2. We have also performed Raman
scattering measurements on several gamma-(Ca,Sr)xCoO2 (0.15 <= x <= 0.35)
samples which show well-defined intercalated Ca/Sr-ordering. The experimental
data show that the intercalated cation ordering could result in visible
alterations on Raman spectral structures. The observations of the spectral
changes along with the variation of the CoO6 stacking, as well as the
intercalated Sr/Ca ordering suggest that the interlayer interaction plays an
important role for understanding the lattice dynamics in this layered system.Comment: 23 pages, 5 figures, Physical Review B, in pres
A layered neural network with three-state neurons optimizing the mutual information
The time evolution of an exactly solvable layered feedforward neural network
with three-state neurons and optimizing the mutual information is studied for
arbitrary synaptic noise (temperature). Detailed stationary
temperature-capacity and capacity-activity phase diagrams are obtained. The
model exhibits pattern retrieval, pattern-fluctuation retrieval and spin-glass
phases. It is found that there is an improved performance in the form of both a
larger critical capacity and information content compared with three-state
Ising-type layered network models. Flow diagrams reveal that saddle-point
solutions associated with fluctuation overlaps slow down considerably the flow
of the network states towards the stable fixed-points.Comment: 17 pages Latex including 6 eps-figure
Transmission of cultural traits in layered ego-centric networks
Although a number of models have been developed to investigate the emergence
of culture and evolutionary phases in social systems, one important aspect has
not yet been sufficiently emphasized. This is the structure of the underlaying
network of social relations serving as channels in transmitting cultural
traits, which is expected to play a crucial role in the evolutionary processes
in social systems. In this paper we contribute to the understanding of the role
of the network structure by developing a layered ego-centric network structure
based model, inspired by the social brain hypothesis, to study transmission of
cultural traits and their evolution in social network. For this model we first
find analytical results in the spirit of mean-field approximation and then to
validate the results we compare them with the results of extensive numerical
simulations.Comment: 10 pages, 2 figure
Seeing Tree Structure from Vibration
Humans recognize object structure from both their appearance and motion;
often, motion helps to resolve ambiguities in object structure that arise when
we observe object appearance only. There are particular scenarios, however,
where neither appearance nor spatial-temporal motion signals are informative:
occluding twigs may look connected and have almost identical movements, though
they belong to different, possibly disconnected branches. We propose to tackle
this problem through spectrum analysis of motion signals, because vibrations of
disconnected branches, though visually similar, often have distinctive natural
frequencies. We propose a novel formulation of tree structure based on a
physics-based link model, and validate its effectiveness by theoretical
analysis, numerical simulation, and empirical experiments. With this
formulation, we use nonparametric Bayesian inference to reconstruct tree
structure from both spectral vibration signals and appearance cues. Our model
performs well in recognizing hierarchical tree structure from real-world videos
of trees and vessels.Comment: ECCV 2018. The first two authors contributed equally to this work.
Project page: http://tree.csail.mit.edu
Non-cubic layered structure of Ba(1-x)K(x)BiO3 superconductor
Bismuthate superconductor Ba(1-x)K(x)BiO3 (x=0.27-0.49, Tc=25-32K) grown by
an electrolysis technique was studied by electron diffraction and
high-resolution electron microscopy. The crystalline structure thereof has been
found to be non-cubic, of the layered nature, and non-centrosymmetric, with the
lattice parameters a ~ ap, c ~ 2ap (ap is a simple cubic perovskite cell
parameter) containing an ordered arrangement of barium and potassium. The
evidence for the layered nature of the bismuthate superconductor removes the
principal crystallographic contradiction between bismuthate and cuprate high-Tc
superconductors.Comment: 4 pages, 3 figures, to be published in Physical Review B as a Rapid
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