706 research outputs found
On Minimizing Crossings in Storyline Visualizations
In a storyline visualization, we visualize a collection of interacting
characters (e.g., in a movie, play, etc.) by -monotone curves that converge
for each interaction, and diverge otherwise. Given a storyline with
characters, we show tight lower and upper bounds on the number of crossings
required in any storyline visualization for a restricted case. In particular,
we show that if (1) each meeting consists of exactly two characters and (2) the
meetings can be modeled as a tree, then we can always find a storyline
visualization with crossings. Furthermore, we show that there
exist storylines in this restricted case that require
crossings. Lastly, we show that, in the general case, minimizing the number of
crossings in a storyline visualization is fixed-parameter tractable, when
parameterized on the number of characters . Our algorithm runs in time
, where is the number of meetings.Comment: 6 pages, 4 figures. To appear at the 23rd International Symposium on
Graph Drawing and Network Visualization (GD 2015
Vortex Tubes in Turbulence Velocity Fields at Reynolds Numbers 300-1300
The most elementary structures of turbulence, i.e., vortex tubes, are studied
using velocity data obtained in a laboratory experiment for boundary layers
with microscale Reynolds numbers 295-1258. We conduct conditional averaging for
enhancements of a small-scale velocity increment and obtain the typical
velocity profile for vortex tubes. Their radii are of the order of the
Kolmogorov length. Their circulation velocities are of the order of the
root-mean-square velocity fluctuation. We also obtain the distribution of the
interval between successive enhancements of the velocity increment as the
measure of the spatial distribution of vortex tubes. They tend to cluster
together below about the integral length and more significantly below about the
Taylor microscale. These properties are independent of the Reynolds number and
are hence expected to be universal.Comment: 8 pages, to appear in Physical Review
Constructing new optimal entanglement witnesses
We provide a new class of indecomposable entanglement witnesses. In 4 x 4
case it reproduces the well know Breuer-Hall witness. We prove that these new
witnesses are optimal and atomic, i.e. they are able to detect the "weakest"
quantum entanglement encoded into states with positive partial transposition
(PPT). Equivalently, we provide a new construction of indecomposable atomic
maps in the algebra of 2k x 2k complex matrices. It is shown that their
structural physical approximations give rise to entanglement breaking channels.
This result supports recent conjecture by Korbicz et. al.Comment: 9 page
Magnetic monopole search by 130 m(2)sr He gas proportional counter
A search experiment for cosmic ray magnetic monopoles was performed by means of atomic induction mechanism by using He mixture gas proportional counters of the calorimeter (130 square meters sr) at the center of the Akeno air shower array. In 3,482 hours operation no monopole candidate was observed. The upper limit of the monopole flux is 1.44 x 10 to the minus 13th power cm-z, sec -1, sr-1 (90% C.L.) for the velocity faster than 7 x 0.0001 c
Facial structures for various notions of positivity and applications to the theory of entanglement
In this expository note, we explain facial structures for the convex cones
consisting of positive linear maps, completely positive linear maps,
decomposable positive linear maps between matrix algebras, respectively. These
will be applied to study the notions of entangled edge states with positive
partial transposes and optimality of entanglement witnesses.Comment: An expository note. Section 7 and Section 8 have been enlarge
KLF11 and association study in Japanese
Aims: Krüppel-like factor 11 (KLF11) is a transcriptional factor of the zinc finger domain family that regulates the expression of insulin. In North European populations, its common functional variant Q62R (rs35927125) is a strong genetic factor for Type 2 diabetes (P = 0.00033, odds ratio for G allele = 1.29, 95% CI 1.12–1.49). We examined the contribution of KLF11 variants to the susceptibility to Type 2 diabetes in a Japanese population.
Methods: By re-sequencing Japanese individuals (n = 24, partly 96), we screened all four exons, exon/intron boundaries and flanking regions of KLF11. Verified single nucleotide polymorphisms (SNPs) were genotyped in 731 initial samples (369 control and 362 case subjects). Subsequently, we tested for association in 1087 samples (524 control and 563 case subjects), which were collected in different districts of Japan from the initial samples.
Results: We identified eight variants, including a novel A/C variant on intron 3, but no mis-sense mutations. In an association study, we failed to find any significant result of SNPs (minor allele frequency 8.2–46.2%) after correcting for multiple testing. Similarly, no haplotypes were associated with Type 2 diabetes. It is notable that the G allele in rs35927125 was completely absent in 1818 Japanese individuals.
Conclusions: Genetic variants in KLF11 are unlikely to have a major effect of Type 2 diabetes in the Japanese population, although they were significantly associated in North European populations. These observations might help to determine the role of KLF11 variants in Type 2 diabetes in different populations
Positive maps, positive polynomials and entanglement witnesses
We link the study of positive quantum maps, block positive operators, and
entanglement witnesses with problems related to multivariate polynomials. For
instance, we show how indecomposable block positive operators relate to
biquadratic forms that are not sums of squares. Although the general problem of
describing the set of positive maps remains open, in some particular cases we
solve the corresponding polynomial inequalities and obtain explicit conditions
for positivity.Comment: 17 pages, 1 figur
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