1,629 research outputs found
D-branes in Yang-Mills theory and Emergent Gauge Symmetry
Four-dimensional supersymmetric SU(N) Yang-Mills theory on a sphere has
highly charged baryon-like states built from anti-symmetric combinations of the
adjoint scalars. We show that these states, which are equivalently described as
holes in a free fermi sea of a reduced matrix model, are D-branes. Their
excitations are stringlike and effectively realize Dirichlet and Neumann
boundary conditions in various directions. The low energy brane dynamics should
realize an emergent gauge theory that is local on a new space. We show that the
Gauss' Law associated to this emergent gauge symmetry appears from
combinatorial identities relating the stringy excitations. Although these
excitations are not BPS, they can be near-BPS and we can hope to study them in
perturbation theory. Accordingly, we show that the Chan-Paton factors expected
for strings propagating on multiple branes arise dynamically, allowing the
emergent gauge symmetry to be non-Abelian.Comment: 55 pages, 9 figures,uses young.sty (included). v2: reference added.
v3: embedded the .sty file in the pape
Simultaneous Spectral-Spatial Feature Selection and Extraction for Hyperspectral Images
In hyperspectral remote sensing data mining, it is important to take into
account of both spectral and spatial information, such as the spectral
signature, texture feature and morphological property, to improve the
performances, e.g., the image classification accuracy. In a feature
representation point of view, a nature approach to handle this situation is to
concatenate the spectral and spatial features into a single but high
dimensional vector and then apply a certain dimension reduction technique
directly on that concatenated vector before feed it into the subsequent
classifier. However, multiple features from various domains definitely have
different physical meanings and statistical properties, and thus such
concatenation hasn't efficiently explore the complementary properties among
different features, which should benefit for boost the feature
discriminability. Furthermore, it is also difficult to interpret the
transformed results of the concatenated vector. Consequently, finding a
physically meaningful consensus low dimensional feature representation of
original multiple features is still a challenging task. In order to address the
these issues, we propose a novel feature learning framework, i.e., the
simultaneous spectral-spatial feature selection and extraction algorithm, for
hyperspectral images spectral-spatial feature representation and
classification. Specifically, the proposed method learns a latent low
dimensional subspace by projecting the spectral-spatial feature into a common
feature space, where the complementary information has been effectively
exploited, and simultaneously, only the most significant original features have
been transformed. Encouraging experimental results on three public available
hyperspectral remote sensing datasets confirm that our proposed method is
effective and efficient
Multi-Trace Superpotentials vs. Matrix Models
We consider N = 1 supersymmetric U(N) field theories in four dimensions with
adjoint chiral matter and a multi-trace tree-level superpotential. We show that
the computation of the effective action as a function of the glueball
superfield localizes to computing matrix integrals. Unlike the single-trace
case, holomorphy and symmetries do not forbid non-planar contributions.
Nevertheless, only a special subset of the planar diagrams contributes to the
exact result. Some of the data of this subset can be computed from the large-N
limit of an associated multi-trace Matrix model. However, the prescription
differs in important respects from that of Dijkgraaf and Vafa for single-trace
superpotentials in that the field theory effective action is not the derivative
of a multi-trace matrix model free energy. The basic subtlety involves the
correct identification of the field theory glueball as a variable in the Matrix
model, as we show via an auxiliary construction involving a single-trace matrix
model with additional singlet fields which are integrated out to compute the
multi-trace results. Along the way we also describe a general technique for
computing the large-N limits of multi-trace Matrix models and raise the
challenge of finding the field theories whose effective actions they may
compute. Since our models can be treated as N = 1 deformations of pure N =2
gauge theory, we show that the effective superpotential that we compute also
follows from the N = 2 Seiberg-Witten solution. Finally, we observe an
interesting connection between multi-trace local theories and non-local field
theory.Comment: 35 pages, LaTeX, 6 EPS figures. v2: typos fixed, v3: typos fixed,
references added, Sec. 5 added explaining how multi-trace theories can be
linearized in traces by addition of singlet fields and the relation of this
approach to matrix model
Analysis of the expression pattern of the BCL11B gene and its relatives in patients with T-cell acute lymphoblastic leukemia
<p>Abstract</p> <p>Background</p> <p>In a human T-cell acute lymphoblastic leukemia (T-ALL) cell line (Molt-4), siRNA-mediated suppression of <it>BCL11B </it>expression was shown to inhibit proliferation and induce apoptosis, functions which may be related to genes involved in apoptosis (such as <it>TNFSF10 </it>and <it>BCL2L1</it>) and TGF-β pathways (such as <it>SPP1</it>and <it>CREBBP</it>).</p> <p>Methods</p> <p>The expression levels of the above mentioned genes and their correlation with the <it>BCL11B </it>gene were analyzed in patients with T-ALL using the TaqMan and SYBR Green I real-time polymerase chain reaction technique.</p> <p>Results</p> <p>Expression levels of <it>BCL11B, BCL2L1</it>, and <it>CREBBP </it>mRNA in T-ALL patients were significantly higher than those from healthy controls (<it>P <</it>0.05). In T-ALL patients, the <it>BCL11B </it>expression level was negatively correlated with the <it>BCL2L1 </it>expression level (<it>r</it><sub>s </sub>= -0.700; <it>P </it><it><</it>0.05), and positively correlated with the <it>SPP1 </it>expression level (<it>r</it><sub>s </sub>= 0.683; <it>P </it><it><</it>0.05). In healthy controls, the <it>BCL11B </it>expression level did not correlate with the <it>TNFSF10</it>, <it>BCL2L1</it>, <it>SPP1</it>, or <it>CREBBP </it>expression levels.</p> <p>Conclusions</p> <p>Over-expression of <it>BCL11B </it>might play a role in anti-apoptosis in T-ALL cells through up-regulation of its downstream genes <it>BCL2L1 </it>and <it>CREBBP</it>.</p
Privileged Prior Information Distillation for Image Matting
Performance of trimap-free image matting methods is limited when trying to
decouple the deterministic and undetermined regions, especially in the scenes
where foregrounds are semantically ambiguous, chromaless, or high
transmittance. In this paper, we propose a novel framework named Privileged
Prior Information Distillation for Image Matting (PPID-IM) that can effectively
transfer privileged prior environment-aware information to improve the
performance of students in solving hard foregrounds. The prior information of
trimap regulates only the teacher model during the training stage, while not
being fed into the student network during actual inference. In order to achieve
effective privileged cross-modality (i.e. trimap and RGB) information
distillation, we introduce a Cross-Level Semantic Distillation (CLSD) module
that reinforces the trimap-free students with more knowledgeable semantic
representations and environment-aware information. We also propose an
Attention-Guided Local Distillation module that efficiently transfers
privileged local attributes from the trimap-based teacher to trimap-free
students for the guidance of local-region optimization. Extensive experiments
demonstrate the effectiveness and superiority of our PPID framework on the task
of image matting. In addition, our trimap-free IndexNet-PPID surpasses the
other competing state-of-the-art methods by a large margin, especially in
scenarios with chromaless, weak texture, or irregular objects.Comment: 15 pages, 7 figure
Sequencing genes in silico using single nucleotide polymorphisms
<p>Abstract</p> <p>Background</p> <p>The advent of high throughput sequencing technology has enabled the 1000 Genomes Project Pilot 3 to generate complete sequence data for more than 906 genes and 8,140 exons representing 697 subjects. The 1000 Genomes database provides a critical opportunity for further interpreting disease associations with single nucleotide polymorphisms (SNPs) discovered from genetic association studies. Currently, direct sequencing of candidate genes or regions on a large number of subjects remains both cost- and time-prohibitive.</p> <p>Results</p> <p>To accelerate the translation from discovery to functional studies, we propose an in silico gene sequencing method (ISS), which predicts phased sequences of intragenic regions, using SNPs. The key underlying idea of our method is to infer diploid sequences (a pair of phased sequences/alleles) at every functional locus utilizing the deep sequencing data from the 1000 Genomes Project and SNP data from the HapMap Project, and to build prediction models using flanking SNPs. Using this method, we have developed a database of prediction models for 611 known genes. Sequence prediction accuracy for these genes is 96.26% on average (ranges 79%-100%). This database of prediction models can be enhanced and scaled up to include new genes as the 1000 Genomes Project sequences additional genes on additional individuals. Applying our predictive model for the KCNJ11 gene to the Wellcome Trust Case Control Consortium (WTCCC) Type 2 diabetes cohort, we demonstrate how the prediction of phased sequences inferred from GWAS SNP genotype data can be used to facilitate interpretation and identify a probable functional mechanism such as protein changes.</p> <p>Conclusions</p> <p>Prior to the general availability of routine sequencing of all subjects, the ISS method proposed here provides a time- and cost-effective approach to broadening the characterization of disease associated SNPs and regions, and facilitating the prioritization of candidate genes for more detailed functional and mechanistic studies.</p
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