1,703 research outputs found
Estimation of glottal closure instants in voiced speech using the DYPSA algorithm
Published versio
Zero-modes of Non-Abelian Solitons in Three Dimensional Gauge Theories
We study non-Abelian solitons of the Bogomol'nyi type in N=2 (d=2+1)
supersymmetric Chern-Simons (CS) and Yang-Mills (YM) theory with a generic
gauge group. In CS theory, we find topological, non-topological and semi-local
(non-)topological vortices of non-Abelian kinds in unbroken, broken and
partially broken vacua. We calculate the number of zero-modes using an index
theorem and then we apply the moduli matrix formalism to realize the moduli
parameters. For the topological solitons we exhaust all the moduli while we
study several examples of the non-topological and semi-local solitons. We find
that the zero-modes of the topological solitons are governed by the moduli
matrix H_0 only and those of the non-topological solitons are governed by both
H_0 and the gauge invariant field \Omega. We prove local uniqueness of the
master equation in the YM case and finally, compare all results between the CS
and YM theories.Comment: 54 pages, 1 figur
A quantitative assessment of group delay methods for identifying glottal closures in voiced speech
Published versio
Group Theory of Non-Abelian Vortices
We investigate the structure of the moduli space of multiple BPS non-Abelian
vortices in U(N) gauge theory with N fundamental Higgs fields, focusing our
attention on the action of the exact global (color-flavor diagonal) SU(N)
symmetry on it. The moduli space of a single non-Abelian vortex, CP(N-1), is
spanned by a vector in the fundamental representation of the global SU(N)
symmetry. The moduli space of winding-number k vortices is instead spanned by
vectors in the direct-product representation: they decompose into the sum of
irreducible representations each of which is associated with a Young tableau
made of k boxes, in a way somewhat similar to the standard group composition
rule of SU(N) multiplets. The K\"ahler potential is exactly determined in each
moduli subspace, corresponding to an irreducible SU(N) orbit of the
highest-weight configuration.Comment: LaTeX 46 pages, 4 figure
Non-Abelian vortex dynamics: Effective world-sheet action
The low-energy vortex effective action is constructed in a wide class of
systems in a color-flavor locked vacuum, which generalizes the results found
earlier in the context of U(N) models. It describes the weak fluctuations of
the non-Abelian orientational moduli on the vortex worldsheet. For instance,
for the minimum vortex in SO(2N) x U(1) or USp(2N) x U(1) gauge theories, the
effective action found is a two-dimensional sigma model living on the Hermitian
symmetric spaces SO(2N)/U(N) or USp(2N)/U(N), respectively. The fluctuating
moduli have the structure of that of a quantum particle state in spinor
representations of the GNO dual of the color-flavor SO(2N) or USp(2N) symmetry,
i.e. of SO(2N) or of SO(2N+1). Applied to the benchmark U(N) model our
procedure reproduces the known CP(N-1) worldsheet action; our recipe allows us
to obtain also the effective vortex action for some higher-winding vortices in
U(N) and SO(2N) theories.Comment: LaTeX, 25 pages, 0 figure
Supersymmetry Breaking on Gauged Non-Abelian Vortices
There are a large number of systems characterized by a completely broken
gauge symmetry, but with an unbroken global color-flavor diagonal symmetry,
i.e., systems in the so-called color-flavor locked phase. If the gauge symmetry
breaking supports vortices, the latter develop non-Abelian orientational
zero-modes and become non-Abelian vortices, a subject of intense study in the
last several years. In this paper we consider the effects of weakly gauging the
full exact global flavor symmetry in such systems, deriving an effective
description of the light excitations in the presence of a vortex. Surprising
consequences are shown to follow. The fluctuations of the vortex orientational
modes get diffused to bulk modes through tunneling processes. When our model is
embedded in a supersymmetric theory, the vortex is still 1/2 BPS saturated, but
the vortex effective action breaks supersymmetry spontaneously.Comment: Latex, 24 pages, 1 figur
Serum Uric Acid and Coronary Heart Disease in 9,458 Incident Cases and 155,084 Controls: Prospective Study and Meta-Analysis
BACKGROUND: It has been suggested throughout the past fifty years that serum uric acid concentrations can help predict the future risk of coronary heart disease (CHD), but the epidemiological evidence is uncertain. METHODS AND FINDINGS: We report a “nested” case-control comparison within a prospective study in Reykjavik, Iceland, using baseline values of serum uric acid in 2,456 incident CHD cases and in 3,962 age- and sex-matched controls, plus paired serum uric acid measurements taken at baseline and, on average, 12 y later in 379 participants. In addition, we conducted a meta-analysis of 15 other prospective studies in eight countries conducted in essentially general populations. Compared with individuals in the bottom third of baseline measurements of serum uric acid in the Reykjavik study, those in the top third had an age- and sex-adjusted odds ratio for CHD of 1.39 (95% confidence interval [CI], 1.23–1.58) which fell to 1.12 (CI, 0.97–1.30) after adjustment for smoking and other established risk factors. Overall, in a combined analysis of 9,458 cases and 155,084 controls in all 16 relevant prospective studies, the odds ratio was 1.13 (CI, 1.07–1.20), but it was only 1.02 (CI, 0.91–1.14) in the eight studies with more complete adjustment for possible confounders. CONCLUSIONS: Measurement of serum uric acid levels is unlikely to enhance usefully the prediction of CHD, and this factor is unlikely to be a major determinant of the disease in general populations
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