155 research outputs found
Center vortices, magnetic condensate and confinement in a simple gauge system
The confining mechanisms of 't Hooft and Mandelstam have a simple microscopic
realization in 3D Z2 gauge theory: the center vortex and the magnetic monopole
condensation are associated, in the set of configurations contributing to the
confining phase, to the presence of two kinds of infinite clusters. These
generate the area law of the large Wilson loops and the universal finite size
effects produced by the quantum fluctuations of the bosonic string describing
the infrared behavior of the flux tube.Comment: 8 pages, 4 eps figures. Contributed to NATO Advanced Research
Workshop on Confinement, Topology, and other Nonperturbative Aspects of QCD,
Stara Lesna, Slovakia, 21-27 Jan 200
Correlating overrepresented upstream motifs to gene expression: a computational approach to regulatory element discovery in eukaryotes
Gene regulation in eukaryotes is mainly effected through transcription
factors binding to rather short recognition motifs generally located upstream
of the coding region. We present a novel computational method to identify
regulatory elements in the upstream region of eukaryotic genes. The genes are
grouped in sets sharing an overrepresented short motif in their upstream
sequence. For each set, the average expression level from a microarray
experiment is determined: If this level is significantly higher or lower than
the average taken over the whole genome, then the overerpresented motif shared
by the genes in the set is likely to play a role in their regulation. The
method was tested by applying it to the genome of Saccharomyces cerevisiae,
using the publicly available results of a DNA microarray experiment, in which
expression levels for virtually all the genes were measured during the diauxic
shift from fermentation to respiration. Several known motifs were correctly
identified, and a new candidate regulatory sequence was determined.Comment: Published version available from
http://www.biomedcentral.com/1471-2105/3/
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