6,885 research outputs found
Chiral phase transition at high temperature and density in the QCD-like theory
The chiral phase transition at finite temperature T and/or chemical potential
is studied using the QCD-like theory with a variational approach. The
``QCD-like theory'' means the improved ladder approximation with an infrared
cutoff in terms of a modified running coupling. The form of
Cornwall-Jackiw-Tomboulis effective potential is modified by the use of the
Schwinger-Dyson equation for generally nonzero current quark mass. We then
calculate the effective potential at finite T and/or and investigate the
phase structure in the chiral limit. We have a second-order phase transition at
MeV for and a first-order one at MeV for T=0. A
tricritical point in the T- plane is found at T=107 MeV, MeV.
The position is close to that of the random matrix model and some version of
the Nambu-Jona-Lasinio model.Comment: 10 pages, 6 figures. Accepted for publication in Physical Review
Fast, Simple Calcium Imaging Segmentation with Fully Convolutional Networks
Calcium imaging is a technique for observing neuron activity as a series of
images showing indicator fluorescence over time. Manually segmenting neurons is
time-consuming, leading to research on automated calcium imaging segmentation
(ACIS). We evaluated several deep learning models for ACIS on the Neurofinder
competition datasets and report our best model: U-Net2DS, a fully convolutional
network that operates on 2D mean summary images. U-Net2DS requires minimal
domain-specific pre/post-processing and parameter adjustment, and predictions
are made on full images at 9K images per minute. It
ranks third in the Neurofinder competition () and is the best model
to exclusively use deep learning. We also demonstrate useful segmentations on
data from outside the competition. The model's simplicity, speed, and quality
results make it a practical choice for ACIS and a strong baseline for more
complex models in the future.Comment: Accepted to 3rd Workshop on Deep Learning in Medical Image Analysis
(http://cs.adelaide.edu.au/~dlmia3/
Isoscalar Giant Quadrupole Resonance State in the Relativistic Approach with the Momentum-Dependent Self-Energies
We study the excited energy of the isoscalar giant quadrupole resonance with
the scaling method in the relativistic many-body framework. In this calculation
we introduce the momentum-dependent parts of the Dirac self-energies arising
from the one-pion exchange on the assumption of the pseudo-vector coupling with
nucleon field. It is shown that this momentum-dependence enhances the Landau
mass significantly and thus suppresses the quadrupole resonance energy even
giving the small Dirac effective mass which causes a problem in the
momentum-independent mean-field theory.Comment: 12pages, 2 Postscript figure
Sensory neurons are required for migration and axon pathfinding of relay motor neurons
The confluence Genil-Guadalquivir in Palma del Río (Córdoba), shows a system composed by four terraces of the Upper and Middle Pleistocene and two episodes of colluvial deposits. The Paleolithic sites (Acheulean and Middle Paleolithic) are linked to lateral bars and colluviums
Improved ESP-index: a practical self-index for highly repetitive texts
While several self-indexes for highly repetitive texts exist, developing a
practical self-index applicable to real world repetitive texts remains a
challenge. ESP-index is a grammar-based self-index on the notion of
edit-sensitive parsing (ESP), an efficient parsing algorithm that guarantees
upper bounds of parsing discrepancies between different appearances of the same
subtexts in a text. Although ESP-index performs efficient top-down searches of
query texts, it has a serious issue on binary searches for finding appearances
of variables for a query text, which resulted in slowing down the query
searches. We present an improved ESP-index (ESP-index-I) by leveraging the idea
behind succinct data structures for large alphabets. While ESP-index-I keeps
the same types of efficiencies as ESP-index about the top-down searches, it
avoid the binary searches using fast rank/select operations. We experimentally
test ESP-index-I on the ability to search query texts and extract subtexts from
real world repetitive texts on a large-scale, and we show that ESP-index-I
performs better that other possible approaches.Comment: This is the full version of a proceeding accepted to the 11th
International Symposium on Experimental Algorithms (SEA2014
Magnetic aftereffect in rare earth-iron-boron magnets
The temperature dependences of the aftereffect coefficient Sv and the coercive force iHc have been measured from 4.2K to 300K on two specimens prepared from sintered magnets of Pr8Y7Fe77B8(sintered at 1060°C and 1100°C). The latter has higher maximum energy products. The Sv values of both have a maximum at 60K and 150K respectively. This is a new behavior which can not be explained by any theory proposed until now. </p
Detecting mode entanglement: The role of coherent states, superselection rules and particle statistics
We discuss the possibility of observing quantum nonlocality using the
so-called mode entanglement, analyzing the differences between different types
of particles in this context. We first discuss the role of coherent states in
such experiments, and we comment on the existence of coherent states in nature.
The discussion of coherent states naturally raises questions about the role of
particle statistics in this problem. Although the Pauli exclusion principle
precludes coherent states with a large number of fermionic particles, we find
that a large number of fermionic coherent states, each containing at most one
particle, can be used to achieve the same effect as a bosonic coherent state
for the purposes of this problem. The discussion of superselection rules arises
naturally in this context, because their applicability to a given situation
prohibits the use of coherent states. This limitation particularly affects the
scenario that we propose for detecting the mode entanglement of fermionic
particles.Comment: 7 pages (two-column
Monopole Oscillations and Dampings in Boson and Fermion Mixture in the Time-Dependent Gross-Pitaevskii and Vlasov Equations
We construct a dynamical model for the time evolution of the boson-fermion
coexistence system. The dynamics of bosons and fermions are formulated with the
time-dependent Gross-Pitaevsky equation and the Vlasov equation. We thus study
the monopole oscillation in the bose-fermi mixture. We find that large damping
exists for fermion oscillations in the mixed system even at zero temperature.Comment: 16 pages text and 12 figure
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