424 research outputs found
The CIFF Proof Procedure for Abductive Logic Programming with Constraints: Theory, Implementation and Experiments
We present the CIFF proof procedure for abductive logic programming with
constraints, and we prove its correctness. CIFF is an extension of the IFF
proof procedure for abductive logic programming, relaxing the original
restrictions over variable quantification (allowedness conditions) and
incorporating a constraint solver to deal with numerical constraints as in
constraint logic programming. Finally, we describe the CIFF system, comparing
it with state of the art abductive systems and answer set solvers and showing
how to use it to program some applications. (To appear in Theory and Practice
of Logic Programming - TPLP)
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
Comments on Supersymmetry Algebra and Contact Term in Matrix String Theory
Following hep-th/0309238 relating the matrix string theory to the light-cone
superstring field theory, we write down two supercharges in the matrix string
theory explicitly. After checking the supersymmetry algebra at the leading
order, we proceed to discuss higher-order contact terms.Comment: 17 pages, no figures, v2: eq. (5.1) and related appendices corrected,
v3: final version to appear in JHE
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
Novel RNA modifications in the nervous system: form and function
Modified RNA molecules have recently been shown to regulate nervous system functions. This mini-review and associated mini-symposium provide an overview of the types and known functions of novel modified RNAs in the nervous system, including covalently modified RNAs, edited RNAs, and circular RNAs. We discuss basic molecular mechanisms involving RNA modifications as well as the impact of modified RNAs and their regulation on neuronal processes and disorders, including neural fate specification, intellectual disability, neurodegeneration, dopamine neuron function, and substance use disorders
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
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