18,416 research outputs found
Topological Superfluid Transition Induced by Periodically Driven Optical Lattice
We propose a scenario to create topological superfluid in a periodically
driven two-dimensional square optical lattice. We study the phase diagram of a
spin-orbit coupled s-wave pairing superfluid in a periodically driven
two-dimensional square optical lattice. We find that a phase transition from a
trivial superfluid to a topological superfluid occurs when the potentials of
the optical lattices are periodically changed. The topological phase is called
Floquet topological superfluid and can host Majorana fermions.Comment: 6 pages, 1 figure
The Effects on , , and from Higher-Dimensional Fermion Representations
Inspired by a new class of walking technicolor models recently proposed using
higher-dimensional technifermions, we consider the oblique corrections from
heavy non-degenerate fermions with two classes of higher-dimensional
representations of the electroweak gauge group itself. One is chiral SM-like,
and the other is vector-like. In both cases, we obtain explicit expressions for
, , in terms of the fermion masses. We find that to keep the
parameter ultraviolet-finite there must be a stringent constraint on the mass
non-degeneracy of a heavy fermion multiplet.Comment: 4 page
The Oblique Corrections from Heavy Scalars in Irreducible Representations
The contributions to , , and from heavy scalars in any irreducible
representation of the electroweak gauge group are
obtained. We find that in the case of a heavy scalar doublet there is a slight
difference between the parameter we have obtained and that in previous
works.Comment: 6 pages, 2 axodraw figures; minor changes, references update
BiMine+: An efficient algorithm for discovering relevant biclusters of DNA microarray data
Biclustering is a very useful tool for analyzing microarray data. It aims to identify maximal groups of genes which are coherent with maximal groups of conditions. In this paper, we propose a biclustering algorithm, called BiMine+, which is able to detect significant biclusters from gene expression data. The proposed algorithm is based on two original features. First, BiMine+ is based on the use of a new tree structure, called Modified Bicluster Enumeration Tree (MBET), on which biclusters are represented by the profile shapes of genes. Second, BiMine+ uses a pruning rule to avoid both trivial biclusters and combinatorial explosion of the search tree. The performance of BiMine+ is assessed on both synthetic and real DNA microarray datasets. Experimental results show that BiMine+ competes favorably with several state-of-the-art biclustering algorithms and is able to extract functionally enriched and biologically relevant biclusters
Symbolic Dynamics Analysis of the Lorenz Equations
Recent progress of symbolic dynamics of one- and especially two-dimensional
maps has enabled us to construct symbolic dynamics for systems of ordinary
differential equations (ODEs). Numerical study under the guidance of symbolic
dynamics is capable to yield global results on chaotic and periodic regimes in
systems of dissipative ODEs which cannot be obtained neither by purely
analytical means nor by numerical work alone. By constructing symbolic dynamics
of 1D and 2D maps from the Poincare sections all unstable periodic orbits up to
a given length at a fixed parameter set may be located and all stable periodic
orbits up to a given length may be found in a wide parameter range. This
knowledge, in turn, tells much about the nature of the chaotic limits. Applied
to the Lorenz equations, this approach has led to a nomenclature, i.e.,
absolute periods and symbolic names, of stable and unstable periodic orbits for
an autonomous system. Symmetry breakings and restorations as well as
coexistence of different regimes are also analyzed by using symbolic dynamics.Comment: 35 pages, LaTeX, 13 Postscript figures, uses psfig.tex. The revision
concerns a bug at the end of hlzfig12.ps which prevented the printing of the
whole .ps file from page 2
Pattern-driven neighborhood search for biclustering of microarray data
Biclustering aims at finding subgroups of genes that show highly correlated behaviors across a subgroup of conditions. Biclustering is a very useful tool for mining microarray data and has various practical applications. From a computational point of view, biclustering is a highly combinatorial search problem and can be solved with optimization methods
BicFinder: a biclustering algorithm for microarray data analysis
In the context of microarray data analysis, biclustering allows the simultaneous identification of a maximum group of genes that show highly correlated expression patterns through a maximum group of experimental conditions (samples). This paper introduces a heuristic algorithm called BicFinder (The BicFinder software is available at: http://www.info.univ-angers.fr/pub/hao/BicFinder.html) for extracting biclusters from microarray data. BicFinder relies on a new evaluation function called Average Correspondence Similarity Index (ACSI) to assess the coherence of a given bicluster and utilizes a directed acyclic graph to construct its biclusters. The performance of BicFinder is evaluated on synthetic and three DNA microarray datasets. We test the biological significance using a gene annotation web-tool to show that our proposed algorithm is able to produce biologically relevant biclusters. Experimental results show that BicFinder is able to identify coherent and overlapping biclusters
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