13,646 research outputs found
Bridging the Gap between Probabilistic and Deterministic Models: A Simulation Study on a Variational Bayes Predictive Coding Recurrent Neural Network Model
The current paper proposes a novel variational Bayes predictive coding RNN
model, which can learn to generate fluctuated temporal patterns from exemplars.
The model learns to maximize the lower bound of the weighted sum of the
regularization and reconstruction error terms. We examined how this weighting
can affect development of different types of information processing while
learning fluctuated temporal patterns. Simulation results show that strong
weighting of the reconstruction term causes the development of deterministic
chaos for imitating the randomness observed in target sequences, while strong
weighting of the regularization term causes the development of stochastic
dynamics imitating probabilistic processes observed in targets. Moreover,
results indicate that the most generalized learning emerges between these two
extremes. The paper concludes with implications in terms of the underlying
neuronal mechanisms for autism spectrum disorder and for free action.Comment: This paper is accepted the 24th International Conference On Neural
Information Processing (ICONIP 2017). The previous submission to arXiv is
replaced by this version because there was an error in Equation
New Measurement of the Relative Scintillation Efficiency of Xenon Nuclear Recoils Below 10 keV
Liquid xenon is an important detection medium in direct dark matter
experiments, which search for low-energy nuclear recoils produced by the
elastic scattering of WIMPs with quarks. The two existing measurements of the
relative scintillation efficiency of nuclear recoils below 20 keV lead to
inconsistent extrapolations at lower energies. This results in a different
energy scale and thus sensitivity reach of liquid xenon dark matter detectors.
We report a new measurement of the relative scintillation efficiency below 10
keV performed with a liquid xenon scintillation detector, optimized for maximum
light collection. Greater than 95% of the interior surface of this detector was
instrumented with photomultiplier tubes, giving a scintillation yield of 19.6
photoelectrons/keV electron equivalent for 122 keV gamma rays. We find that the
relative scintillation efficiency for nuclear recoils of 5 keV is 0.14, staying
constant around this value up to 10 keV. For higher energy recoils we measure a
value around 20%, consistent with previously reported data. In light of this
new measurement, the XENON10 experiment's results on spin-independent
WIMP-nucleon cross section, which were calculated assuming a constant 0.19
relative scintillation efficiency, change from cm to
cm for WIMPs of mass 100 GeV/c, and from
cm to cm for WIMPs of mass 30
GeV/c.Comment: 8 pages, 8 figure
Stabilization of the number of Bose-Einstein condensed atoms in evaporative cooling via three-body recombination loss
The dynamics of evaporative cooling of magnetically trapped Rb atoms
is studied on the basis of the quantum kinetic theory of a Bose gas. We carried
out the quantitative calculations of the time evolution of conventional
evaporative cooling where the frequency of the radio-frequency magnetic field
is swept exponentially. This "exponential-sweep cooling" is known to become
inefficient at the final stage of the cooling process due to a serious
three-body recombination loss. We precisely examine how the growth of a
Bose-Einstein condensate depends on the experimental parameters of evaporative
cooling, such as the initial number of trapped atoms, the initial temperature,
and the bias field of a magnetic trap. It is shown that three-body
recombination drastically depletes the trapped Rb atoms as the system
approaches the quantum degenerate region and the number of condensed atoms
finally becomes insensitive to these experimental parameters. This result
indicates that the final number of condensed atoms is well stabilized by a
large nonlinear three-body loss against the fluctuations of experimental
conditions in evaporative cooling.Comment: 7 pages, REVTeX4, 8 eps figures, Phys. Rev A in pres
Glycosylation pattern of brush border-associated glycoproteins in enterocyte-like cells: involvement of complex-type N-glycans in apical trafficking
We have previously reported that galectin-4, a tandem repeat-type galectin, regulates the raft-dependent delivery of glycoproteins to the apical brush border membrane of enterocyte-like HT-29 cells. N-Acetyllactosamine-containing glycans, known as galectin ligands, were found enriched in detergent-resistant membranes. Here, we analyzed the potential contribution of N-and/ or O-glycans in this mechanism. Structural studies were carried out on the brush border membrane-enriched fraction using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and nano-ESI-QTOF-MS/MS. The pattern of N-glycans was very heterogeneous, with the presence of high mannose- and hybrid-type glycans as well as a multitude of complex-type glycans. In contrast, the pattern of O-glycans was very simple with the presence of two major core type 1 O-glycans, sialylated and bisialylated T-antigen structures {[}Neu5Ac alpha 2-3Gal beta 1-3GalNAc-ol and Neu5Ac alpha 2-3Gal beta 1 -3(Neu5Ac alpha 2-6)GalNAc-ol]. Thus, N-glycans rather than O-glycans contain the N-acetyllactosamine recognition signals for the lipid raft-based galectin-4-dependent apical delivery. In the presence of 1-deoxymannojirimycin, a drug which inhibits the generation of hybrid-type or complex type N-glycans, the extensively O-glycosylated mucin-like MUC1 glycoprotein was not delivered to the apical brush border but accumulated inside the cells. Altogether, our data demonstrate the crucial role of complex N-glycans in the galectin-4-dependent delivery of glycoproteins to the apical brush border membrane of enterocytic HT-29 cells
Parity-broken ground state for the spin-1 pyrochlore antiferromagnet
The ground-state properties of the spin-1 pyrochlore antiferromagnet are
studied by applying the VBS-like tetrahedron-unit decomposition to the original
spin system. The symmetrization required on every vertex is taken into account
by introducing a ferromagnetic coupling. The pairwise effective Hamiltonian
between the adjacent tetrahedrons is obtained by considering the next nearest
neighbor and the third neighbor exchange interactions. We find that the
transverse component of the spin chirality exhibits a long-range order,
breaking the parity symmetry of the tetrahedral group, while the chirality
itself is not broken.Comment: 4 pages, 3 figures, REVTeX(ver.3.1
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