5,959 research outputs found
Charged and superconducting vortices in dense quark matter
Quark matter at astrophysical densities may contain stable vortices due to
the spontaneous breaking of hypercharge symmetry by kaon condensation. We argue
that these vortices could be both charged and electrically superconducting.
Current carrying loops (vortons) could be long lived and play a role in the
magnetic and transport properties of this matter. We provide a scenario for
vorton formation in protoneutron stars.Comment: Replaced with the published version. A typographical error in Eq. 2
is correcte
Sum rules and three point functions
Sum rules constraining the R-current spectral densities are derived
holographically for the case of D3-branes, M2-branes and M5-branes all at
finite chemical potentials. In each of the cases the sum rule relates a certain
integral of the spectral density over the frequency to terms which depend both
on long distance physics, hydrodynamics and short distance physics of the
theory. The terms which which depend on the short distance physics result from
the presence of certain chiral primaries in the OPE of two R-currents which are
turned on at finite chemical potential. Since these sum rules contain
information of the OPE they provide an alternate method to obtain the structure
constants of the two R-currents and the chiral primary. As a consistency check
we show that the 3 point function derived from the sum rule precisely matches
with that obtained using Witten diagrams.Comment: 41 page
Shear sum rules at finite chemical potential
We derive sum rules which constrain the spectral density corresponding to the
retarded propagator of the T_{xy} component of the stress tensor for three
gravitational duals. The shear sum rule is obtained for the gravitational dual
of the N=4 Yang-Mills, theory of the M2-branes and M5-branes all at finite
chemical potential. We show that at finite chemical potential there are
additional terms in the sum rule which involve the chemical potential. These
modifications are shown to be due to the presence of scalars in the operator
product expansion of the stress tensor which have non-trivial vacuum
expectation values at finite chemical potential.Comment: The proof for the absence of branch cuts is corrected.Results
unchange
Higher spin fermions in the BTZ black hole
Recently it has been shown that the wave equations of bosonic higher spin
fields in the BTZ background can be solved exactly. In this work we extend this
analysis to fermionic higher spin fields. We solve the wave equations for
arbitrary half-integer spin fields in the BTZ black hole background and obtain
exact expressions for their quasinormal modes. These quasinormal modes are
shown to agree precisely with the poles of the corresponding two point function
in the dual conformal field theory as predicted by the AdS/CFT correspondence.
We also obtain an expression for the 1-loop determinant in terms of the
quasinormal modes and show it agrees with that obtained by integrating the heat
kernel found by group theoretic methods.Comment: 29 page
Distilling Missing Modality Knowledge from Ultrasound for Endometriosis Diagnosis with Magnetic Resonance Images
Endometriosis is a common chronic gynecological disorder that has many
characteristics, including the pouch of Douglas (POD) obliteration, which can
be diagnosed using Transvaginal gynecological ultrasound (TVUS) scans and
magnetic resonance imaging (MRI). TVUS and MRI are complementary non-invasive
endometriosis diagnosis imaging techniques, but patients are usually not
scanned using both modalities and, it is generally more challenging to detect
POD obliteration from MRI than TVUS. To mitigate this classification imbalance,
we propose in this paper a knowledge distillation training algorithm to improve
the POD obliteration detection from MRI by leveraging the detection results
from unpaired TVUS data. More specifically, our algorithm pre-trains a teacher
model to detect POD obliteration from TVUS data, and it also pre-trains a
student model with 3D masked auto-encoder using a large amount of unlabelled
pelvic 3D MRI volumes. Next, we distill the knowledge from the teacher TVUS POD
obliteration detector to train the student MRI model by minimizing a regression
loss that approximates the output of the student to the teacher using unpaired
TVUS and MRI data. Experimental results on our endometriosis dataset containing
TVUS and MRI data demonstrate the effectiveness of our method to improve the
POD detection accuracy from MRI.Comment: This paper is accepted by 2023 IEEE 20th International Symposium on
Biomedical Imaging(ISBI 2023
Higher spin quasinormal modes and one-loop determinants in the BTZ black hole
We solve the wave equations of arbitrary integer spin fields in the BTZ black
hole background and obtain exact expressions for their quasinormal modes. We
show that these quasinormal modes precisely agree with the location of the
poles of the corresponding two point function in the dual conformal field
theory as predicted by the AdS/CFT correspondence. We then use these
quasinormal modes to construct the one-loop determinant of the higher spin
field in the thermal BTZ background. This is shown to agree with that obtained
from the corresponding heat kernel constructed recently by group theoretic
methods.Comment: 47 page
String Theory and Quantum Chromodynamics
I review recent progress on the connection between string theory and quantum
chromodynamics in the context of the gauge/gravity duality. Emphasis is placed
on conciseness and conceptual aspects rather than on technical details. Topics
covered include the large-Nc limit of gauge theories, the gravitational
description of gauge theory thermodynamics and hydrodynamics, and
confinement/deconfinement thermal phase transitions.Comment: 38 pages, 24 figures. Lectures given at the RTN Winter School on
"Strings, Supergravity and Gauge Theories" at CERN on January 15-19, 200
Hydrodynamics of R-charged D1-branes
We study the hydrodynamic properties of strongly coupled Yang-Mills
theory of the D1-brane at finite temperature and at a non-zero density of
R-charge in the framework of gauge/gravity duality. The gravity dual
description involves a charged black hole solution of an
Einstein-Maxwell-dilaton system in 3 dimensions which is obtained by a
consistent truncation of the spinning D1-brane in 10 dimensions. We evaluate
thermal and electrical conductivity as well as the bulk viscosity as a function
of the chemical potential conjugate to the R-charges of the D1-brane. We show
that the ratio of bulk viscosity to entropy density is independent of the
chemical potential and is equal to . The thermal conductivity and bulk
viscosity obey a relationship similar to the Wiedemann-Franz law. We show that
at the boundary of thermodynamic stability, the charge diffusion mode becomes
unstable and the transport coefficients exhibit critical behaviour. Our method
for evaluating the transport coefficients relies on expressing the second order
differential equations in terms of a first order equation which dictates the
radial evolution of the transport coefficient. The radial evolution equations
can be solved exactly for the transport coefficients of our interest. We
observe that transport coefficients of the D1-brane theory are related to that
of the M2-brane by an overall proportionality constant which sets the
dimensions.Comment: 57 pages, 12 figure
Repurposing Albendazole: new potential as a chemotherapeutic agent with preferential activity against HPV-negative head and neck squamous cell cancer.
Albendazole is an anti-helminthic drug that has been shown to exhibit anti-cancer properties, however its activity in head and neck squamous cell cancer (HNSCC) was unknown. Using a series of in vitro assays, we assessed the ability of albendazole to inhibit proliferation in 20 HNSCC cell lines across a range of albendazole doses (1 nM-10 μM). Cell lines that responded to treatment were further examined for cell death, inhibition of migration and cell cycle arrest. Thirteen of fourteen human papillomavirus-negative HNSCC cell lines responded to albendazole, with an average IC50 of 152 nM. In contrast, only 3 of 6 human papillomavirus-positive HNSCC cell lines responded. Albendazole treatment resulted in apoptosis, inhibition of cell migration, cell cycle arrest in the G2/M phase and altered tubulin distribution. Normal control cells were not measurably affected by any dose tested. This study indicates that albendazole acts to inhibit the proliferation of human papillomavirus-negative HNSCC cell lines and thus warrants further study as a potential chemotherapeutic agent for patients suffering from head and neck cancer
Relaxed Softmax for learning from Positive and Unlabeled data
In recent years, the softmax model and its fast approximations have become
the de-facto loss functions for deep neural networks when dealing with
multi-class prediction. This loss has been extended to language modeling and
recommendation, two fields that fall into the framework of learning from
Positive and Unlabeled data. In this paper, we stress the different drawbacks
of the current family of softmax losses and sampling schemes when applied in a
Positive and Unlabeled learning setup. We propose both a Relaxed Softmax loss
(RS) and a new negative sampling scheme based on Boltzmann formulation. We show
that the new training objective is better suited for the tasks of density
estimation, item similarity and next-event prediction by driving uplifts in
performance on textual and recommendation datasets against classical softmax.Comment: 9 pages, 5 figures, 2 tables, published at RecSys 201
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