526 research outputs found
Probing signatures of bounce inflation with current observations
The aim of this paper is to probe the features of the bouncing cosmology with
the current observational data. Basing on bounce inflation model, with high
derivative term, we propose a general parametrization of primordial power
spectrum which includes the typical bouncing parameters, such as bouncing
time-scale, and energy scale. By applying Markov Chain Monto Carlo analysis
with current data combination of Planck 2015, BAO and JLA, we report the
posterior probability distributions of the parameters. We find that, bouncing
models can well explain CMB observations, especially the deficit and
oscillation on large scale in TT power spectrum.Comment: 17 pages, 8 figure
WordSpy: identifying transcription factor binding motifs by building a dictionary and learning a grammar
Transcription factor (TF) binding sites or motifs (TFBMs) are functional cis-regulatory DNA sequences that play an essential role in gene transcriptional regulation. Although many experimental and computational methods have been developed, finding TFBMs remains a challenging problem. We propose and develop a novel dictionary based motif finding algorithm, which we call WordSpy. One significant feature of WordSpy is the combination of a word counting method and a statistical model which consists of a dictionary of motifs and a grammar specifying their usage. The algorithm is suitable for genome-wide motif finding; it is capable of discovering hundreds of motifs from a large set of promoters in a single run. We further enhance WordSpy by applying gene expression information to separate true TFBMs from spurious ones, and by incorporating negative sequences to identify discriminative motifs. In addition, we also use randomly selected promoters from the genome to evaluate the significance of the discovered motifs. The output from WordSpy consists of an ordered list of putative motifs and a set of regulatory sequences with motif binding sites highlighted. The web server of WordSpy is available at
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