364 research outputs found
Association between sleep duration and diabetes mellitus: Isfahan Healthy Heart Program
Background: Recent studies revealed an association between sleep disturbance and metabolic disorders, such as obesity and metabolic syndrome. An aim of this study was to assess the relation between sleep duration and diabetes mellitus in a representative sample of the Iranian population.Materials and Methods: Participants were 12514 individuals, (6123 men and 6391 women) studied in the baseline survey of a community based program entitled Isfahan healthy heart program (IHHP). Sleep time was obtained by validated questionnaire. Diabetes mellitus was defined as fasting glucose over 126 mg/dl or 2 hour post prandial glucose at glucose tolerance test over 200 mg/dl, or if the patient was on diabetic medication. The relation between the sleep time and diabetes was examined using categorical logistic regression with adjustment for sex, body mass index and waist circumference.Results: Compared with those, sleeping 7.8 hours per night, the individuals with sleeping time of 5 hours or less and aged <60 years had an increased odd ratio for diabetes and an impaired glucose tolerance. (OR = 1.37 and 95% CI = 1.13,1.67).Conclusion: Sleep duration of 5 hours or less in individuals under age 60 years is associated with an increased prevalence of diabetes mellitus and an impaired glucose tolerance test. This finding should be confirmed in longitudinal studies.Key words: Diabetes mellitus, glucose tolerance, slee
Factorization in Formal Languages
We consider several novel aspects of unique factorization in formal
languages. We reprove the familiar fact that the set uf(L) of words having
unique factorization into elements of L is regular if L is regular, and from
this deduce an quadratic upper and lower bound on the length of the shortest
word not in uf(L). We observe that uf(L) need not be context-free if L is
context-free.
Next, we consider variations on unique factorization. We define a notion of
"semi-unique" factorization, where every factorization has the same number of
terms, and show that, if L is regular or even finite, the set of words having
such a factorization need not be context-free. Finally, we consider additional
variations, such as unique factorization "up to permutation" and "up to
subset"
Bethe Ansatz Equations for General Orbifolds of N=4 SYM
We consider the Bethe Ansatz Equations for orbifolds of N =4 SYM w.r.t. an
arbitrary discrete group. Techniques used for the Abelian orbifolds can be
extended to the generic non-Abelian case with minor modifications. We show how
to make a transition between the different notations in the quiver gauge
theory.Comment: LaTeX, 66 pages, 9 eps figures, minor corrections, references adde
Recurrent Partial Words
Partial words are sequences over a finite alphabet that may contain wildcard
symbols, called holes, which match or are compatible with all letters; partial
words without holes are said to be full words (or simply words). Given an
infinite partial word w, the number of distinct full words over the alphabet
that are compatible with factors of w of length n, called subwords of w, refers
to a measure of complexity of infinite partial words so-called subword
complexity. This measure is of particular interest because we can construct
partial words with subword complexities not achievable by full words. In this
paper, we consider the notion of recurrence over infinite partial words, that
is, we study whether all of the finite subwords of a given infinite partial
word appear infinitely often, and we establish connections between subword
complexity and recurrence in this more general framework.Comment: In Proceedings WORDS 2011, arXiv:1108.341
Solvable models of strings in homogeneous plane wave backgrounds
We solve closed string theory in all regular homogeneous plane-wave
backgrounds with homogeneous NS three-form field strength and a dilaton. The
parameters of the model are constant symmetric and anti-symmetric matrices
k_{ij} and f_{ij} associated with the metric, and a constant anti-symmetric
matrix h_{ij} associated with the NS field strength. In the light-cone gauge
the rotation parameters f_{ij} have a natural interpretation as a constant
magnetic field. This is a generalisation of the standard Landau problem with
oscillator energies now being non-trivial functions of the parameters f_{ij}
and k_{ij}. We develop a general procedure for solving linear but non-diagonal
equations for string coordinates, and determine the corresponding oscillator
frequencies, the light-cone Hamiltonian and level matching condition. We
investigate the resulting string spectrum in detail in the four-dimensional
case and compare the results with previously studied examples. Throughout we
will find that the presence of the rotation parameter f_{ij} can lead to
certain unusual and unexpected features of the string spectrum like new
massless states at non-zero string levels, stabilisation of otherwise unstable
(tachyonic) modes, and discrete but not positive definite string oscillator
spectra.Comment: 48 pages, LaTeX2e, v2: additional reference and cosmetic correction
Classification of IIB backgrounds with 28 supersymmetries
We show that all IIB backgrounds with strictly 28 supersymmetries are locally
isometric to the plane wave solution of arXiv:hep-th/0206195. Moreover, we
demonstrate that all solutions with more than 26 supersymmetries and only
5-form flux are maximally supersymmetric. The N=28 plane wave solution is a
superposition of the maximally supersymmetric IIB plane wave with a heterotic
string solution. We investigate the propagation of strings in this background,
find the spectrum and give the string light-cone Hamiltonian.Comment: 30 pages, typos correcte
Parallelisable Heterotic Backgrounds
We classify the simply-connected supersymmetric parallelisable backgrounds of
heterotic supergravity. They are all given by parallelised Lie groups admitting
a bi-invariant lorentzian metric. We find examples preserving 4, 8, 10, 12, 14
and 16 of the 16 supersymmetries.Comment: 17 pages, AMSLaTe
Collagen Type XIX Regulates Cardiac Extracellular Matrix Structure and Ventricular Function
The cardiac extracellular matrix plays essential roles in homeostasis and injury responses. Although the role of fibrillar collagens have been thoroughly documented, the functions of non-fibrillar collagen members remain underexplored. These include a distinct group of non-fibrillar collagens, termed, fibril-associated collagens with interrupted triple helices (FACITs). Recent reports of collagen type XIX (encoded by Col19a1) expression in adult heart and evidence of its enhanced expression in cardiac ischemia suggest important functions for this FACIT in cardiac ECM structure and function. Here, we examined the cellular source of collagen XIX in the adult murine heart and evaluated its involvement in ECM structure and ventricular function. Immunodetection of collagen XIX in fractionated cardiovascular cell lineages revealed fibroblasts and smooth muscle cells as the primary sources of collagen XIX in the heart. Based on echocardiographic and histologic analyses, Col19a1 null (Col19a1(N/N)) mice exhibited reduced systolic function, thinning of left ventricular walls, and increased cardiomyocyte cross-sectional areas—without gross changes in myocardial collagen content or basement membrane morphology. Col19a1(N/N) cardiac fibroblasts had augmented expression of several enzymes involved in the synthesis and stability of fibrillar collagens, including PLOD1 and LOX. Furthermore, second harmonic generation-imaged ECM derived from Col19a1(N/N) cardiac fibroblasts, and transmission electron micrographs of decellularized hearts from Col19a1(N/N) null animals, showed marked reductions in fibrillar collagen structural organization. Col19a1(N/N) mice also displayed enhanced phosphorylation of focal adhesion kinase (FAK), signifying de-repression of the FAK pathway—a critical mediator of cardiomyocyte hypertrophy. Collectively, we show that collagen XIX, which had a heretofore unknown role in the mammalian heart, participates in the regulation of cardiac structure and function—potentially through modulation of ECM fibrillar collagen structural organization. Further, these data suggest that this FACIT may modify ECM superstructure via acting at the level of the fibroblast to regulate their expression of collagen synthetic and stabilization enzymes
Phases of Thermal N=2 Quiver Gauge Theories
We consider large N U(N)^M thermal N=2 quiver gauge theories on S^1 x S^3. We
obtain a phase diagram of the theory with R-symmetry chemical potentials,
separating a low-temperature/high-chemical potential region from a
high-temperature/low-chemical potential region. In close analogy with the N=4
SYM case, the free energy is of order O(1) in the low-temperature region and of
order O(N^2 M) in the high-temperature phase. We conclude that the N=2 theory
undergoes a first order Hagedorn phase transition at the curve in the phase
diagram separating these two regions. We observe that in the region of zero
temperature and critical chemical potential the Hilbert space of gauge
invariant operators truncates to smaller subsectors. We compute a l-loop
effective potential with non-zero VEV's for the scalar fields in a sector where
the VEV's are homogeneous and mutually commuting. At low temperatures the
eigenvalues of these VEV's are distributed uniformly over an S^5/Z_M which we
interpret as the emergence of the S^5/Z_M factor of the holographically dual
geometry AdS_5 x S^5/Z_M. Above the Hagedorn transition the eigenvalue
distribution of the Polyakov loop opens a gap, resulting in the collapse of the
joint eigenvalue distribution from S^5/Z_M x S^1 into S^6/Z_M.Comment: 40 pages text + 15 pages appendix, 3 figures, latex; v2: one minor
typo corrected and typeset in JHEP format; v3: computation of saddle points
in Sec. 4.2 improved, discussion of stability of saddle points added in Sec.
6.2, minor changes, ref. adde
All supersymmetric solutions of minimal supergravity in six dimensions
A general form for all supersymmetric solutions of minimal supergravity in
six dimensions is obtained. Examples of new supersymmetric solutions are
presented. It is proven that the only maximally supersymmetric solutions are
flat space, AdS_3 x S^3 and a plane wave. As an application of the general
solution, it is shown that any supersymmetric solution with a compact horizon
must have near-horizon geometry R^{1,1} x T^4, R^{1,1} x K3 or identified AdS_3
x S^3.Comment: 40 pages. v2: two references adde
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