29,089 research outputs found
The regulatory function of sphingosine-1-phosphate signaling axis on regulatory T cells in colorectal cancer
In tumors associated with inflammation such as inflammatory bowel disease (IBD) and colorectal cancer (CRC), high numbers of regulatory T cells (Tregs) are associated with both favorable and poor prognoses. The functions of Tregs in CRC remain elusive and have yet to be clearly defined. With new evidence supporting many subsets of Tregs, the research on the development and functions of these cells has begun to come to fruition. The sphingosine 1 phosphate (S1P) pathway was recently reported to regulate the development and function of regulatory T cells. This pathway may shine new light into the pleiotropic nature of these cells in cancer. In this review, we will examine current literature on the many functions of Tregs in CRC and highlight the significance of the S1P signaling pathway in Treg development/function with the implication of novel therapeutic strategies in treatment of CRC patients
Effect of edge decoration on the energy spectrum of semi-infinite lattices
Analytical studies of the effect of edge decoration on the energy spectrum of
semi-infinite one-dimensional (1D) lattice chain with Peierls phase transition
and zigzag edged graphene (ZEG) are presented by means of transfer matrix
method, in the frame of which the sufficient and necessary conditions for the
existence of the edge states are determined. For 1D lattice chain, the
zero-energy edge state exists when Peierls phase transition happens regardless
whether the decoration exists or not, while the non-zero-energy edge states can
be induced and manipulated through adjusting the edge decoration. On the other
hand, the semi-infinite ZEG model with nearest-neighbor interaction can be
mapped into the 1D lattice chain case. The non-zero-energy edge states can be
induced by the decoration as well, and we can obtain the condition of the
decoration on the edge for the existence of the novel edge states.Comment: 6 pages,4 figure
An investigation of star formation and dust attenuation in major mergers using ultraviolet and infrared data
Merger processes play an important role in galaxy formation and evolution. To
study the influence of merger processes on the evolution of dust properties and
cosmic star formation rate, we investigate a local sample of major merger
galaxies and a control sample of isolated galaxies using GALEX ultraviolet (UV)
and Spitzer infrared (IR) images. Through a statistical study, we find that
dust attenuation in merger galaxies is enhanced with respect to isolated
galaxies. We find this enhancement is contributed mainly by spiral galaxies in
spiral-spiral (S-S) pairs, and increases with the increasing stellar mass of a
galaxy. Combining the IR and UV parts of star formation rates (SFRs), we then
calculated the total SFRs and specific star formation rates (SSFRs). We find
the SSFRs to be enhanced in merger galaxies. This enhancement depends on galaxy
stellar mass and the companion's morphology, but depends little on whether the
galaxy is a primary or secondary component or on the separation between two
components. These results are consistent with a previous study based only on IR
images. In addition, we investigate the nuclear contributions to SFRs. SFRs in
paired galaxies are more concentrated in the central part of the galaxies than
in isolate galaxies. Our studies of dust attenuation show that the nuclear
parts of pairs most resemble ULIRGs. Including UV data in the present work not
only provides reliable information on dust attenuation, but also refines
analyses of SFRs.Comment: 21 pages, 21 figure
Object Picture of Quasinormal Modes for Stringy Black Holes
We study the quasinormal modes (QNMs) for stringy black holes. By using
numerical calculation, the relations between the QNMs and the parameters of
black holes are minutely shown. For (1+1)-dimensional stringy black hole, the
real part of the quasinormal frequency increases and the imaginary part of the
quasinormal frequency decreases as the mass of the black hole increases.
Furthermore, the dependence of the QNMs on the charge of the black hole and the
flatness parameter is also illustrated. For (1+3)-dimensional stringy black
hole, increasing either the event horizon or the multipole index, the real part
of the quasinormal frequency decreases. The imaginary part of the quasinormal
frequency increases no matter whether the event horizon is increased or the
multipole index is decreased.Comment: 4 pages, 5 figure
Gluon-gluon contributions to the production of continuum diphoton pairs at hadron colliders
We compute the contributions to continuum photon pair production at hadron
colliders from processes initiated by gluon-gluon and gluon-quark scattering
into two photons through a four-leg virtual quark loop. Complete two-loop cross
sections in perturbative quantum chromodynamics are combined with contributions
from soft parton radiation resummed to all orders in the strong coupling
strength. The structure of the resummed cross section is examined in detail,
including a new type of unintegrated parton distribution function affecting
azimuthal angle distributions of photons in the pair's rest frame. As a result
of this analysis, we predict diphoton transverse momentum distributions in
gluon-gluon scattering in wide ranges of kinematic parameters at the Fermilab
Tevatron collider and the CERN Large Hadron Collider.Comment: 28 pages, 11 figures; published versio
Sediment Loss and Its Cause in Puerto Rico Watersheds
A major environmental concern in the Commonwealth of Puerto Rico is increased sediment load to water reservoirs, to estuaries, and finally to coral reef areas outside the estuaries. Sediment deposition has significantly reduced the storage capacity of reservoirs, and sediments, with their associated contaminants and nutrients that are adsorbed, can stress corals and negatively impact reef health. To prevent and manage sediment loss it is therefore important to understand local soil erosion and sediment transport processes. The main objective of this study was to determine the influence of landscape characteristics on sediment loss. We analyzed available precipitation and sediment data collected in Puerto Rico during the past three decades, as well as information on land use, soil properties, and topography. Our partial least squares analysis was not very successful in identifying major factors associated with sediment loss due to the complexity of the study\u27s watersheds; however, it was found that topography and rainfall factors do not play a leading role. Sediment loss from the ridge watersheds in Puerto Rico was mainly caused by interactions of development, heavy rainfall events (especially hurricanes), and steep mountainous slopes associated with the ridges. These results improve our understanding of sediment loss resulting from changes in land use/cover within a Puerto Rico watershed, and allow stakeholders to make more informed decisions about land use planning
Exact Hybrid Covariance Thresholding for Joint Graphical Lasso
This paper considers the problem of estimating multiple related Gaussian
graphical models from a -dimensional dataset consisting of different
classes. Our work is based upon the formulation of this problem as group
graphical lasso. This paper proposes a novel hybrid covariance thresholding
algorithm that can effectively identify zero entries in the precision matrices
and split a large joint graphical lasso problem into small subproblems. Our
hybrid covariance thresholding method is superior to existing uniform
thresholding methods in that our method can split the precision matrix of each
individual class using different partition schemes and thus split group
graphical lasso into much smaller subproblems, each of which can be solved very
fast. In addition, this paper establishes necessary and sufficient conditions
for our hybrid covariance thresholding algorithm. The superior performance of
our thresholding method is thoroughly analyzed and illustrated by a few
experiments on simulated data and real gene expression data
Accessing tri-gluon correlations in the nucleon via the single spin asymmetry in open charm production
We calculate the single transverse-spin asymmetry for open charm production
in collisions within the QCD collinear factorization approach. We include
contributions from both twist-three quark-gluon and tri-gluon correlation
functions. We find that the quark-gluon correlation functions alone generate
only a very small asymmetry for open charm production in the kinematic region
of current interest at RHIC, so that the observation of any significant
single-spin asymmetry would be a clear indication of the presence of tri-gluon
correlations inside a polarized proton. We furthermore demonstrate that the
tri-gluon contribution could be very different for the production of and
mesons. These features make the single spin asymmetry in open charm
production in polarized collisions at RHIC an excellent probe of tri-gluon
correlation functions.Comment: 10 pages, 7 figure
Berry's phase in the multimode Peierls states
It is shown that Berry's phase associated with the adiabatic change of local
variables in the Hamiltonian can be used to characterize the multimode Peierls
state, which has been proposed as a new type of the ground state of the
two-dimensional(2D) systems with the electron-lattice interaction.Comment: 2 pages, 2 figure
Penerapan Sentiment Analysis Pada Hasil Evaluasi Dosen Dengan Metode Support Vector Machine
The quality of lectures can be determined by some feedbacks from students. From the feedbacks, we can give appreciations for those lectures who get good feedback from students, and evaluations for those who get bad feedback. The problem is classifying large size of feedbacks manually isn\u27t effective and took a lot of time. Therefore, we need a system that can classify feedbacks automatically. These feedbacks will be classified into positive, negative, and neutral, usually called as sentiment analysis. Sentiment analysis implementation can be done by several methods, one of them that has a good accuracy is Support Vector Machine (SVM). SVM performance in this research is measured with the level of accuracy. The number of accuracy indicate the success level of system. The conclusion of this research is factors that affects the accuracy. The factors are the range of each classes and number of unique words in the training document
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