1,892 research outputs found
Timelike deeply virtual Compton scattering with a linearly polarized real (or quasi-real) photon beam
We calculate timelike virtual Compton scattering amplitudes in the
generalized Bjorken scaling regime and focus on a new polarization asymmetry in
the scattering process with a linearly polarized photon beam in the medium
energy range, which will be studied intensely at JLab12 experiments. We
demonstrate that new observables help us to access the polarized quark and
gluon generalized parton distributions and .Comment: To appear in the proceedings XXII. International Workshop on Deep
Inelastic Scattering and Related Subjects (DIS 2014), 28 April - 2 May 2014,
Warsaw, Polan
Triangle-free geometric intersection graphs with large chromatic number
Several classical constructions illustrate the fact that the chromatic number
of a graph can be arbitrarily large compared to its clique number. However,
until very recently, no such construction was known for intersection graphs of
geometric objects in the plane. We provide a general construction that for any
arc-connected compact set in that is not an axis-aligned
rectangle and for any positive integer produces a family of
sets, each obtained by an independent horizontal and vertical scaling and
translation of , such that no three sets in pairwise intersect
and . This provides a negative answer to a question of
Gyarfas and Lehel for L-shapes. With extra conditions, we also show how to
construct a triangle-free family of homothetic (uniformly scaled) copies of a
set with arbitrarily large chromatic number. This applies to many common
shapes, like circles, square boundaries, and equilateral L-shapes.
Additionally, we reveal a surprising connection between coloring geometric
objects in the plane and on-line coloring of intervals on the line.Comment: Small corrections, bibliography updat
Dimension is polynomial in height for posets with planar cover graphs
We show that height~ posets that have planar cover graphs have dimension
. Previously, this upper bound was . Planarity plays a key
role in our arguments, since there are posets such that (1) dimension is
exponential in height and (2) the cover graph excludes as a minor
It\u27s Time: A Meta-Analysis on the Self-Control-Deviance Link
Purpose The current meta-analysis examines the link between self-control and measures of crime and deviance, taking stock of the empirical status of self-control theory and focusing on work published between 2000 and 2010.
Methods A total of 796 studies were reviewed for inclusion/exclusion criteria and yielded a final study sample of 99 studies (88 cross-sectional and 19 longitudinal effect sizes, analyzed separately). Random effects mean correlations between self-control and deviance were analyzed for cross-sectional and longitudinal studies, respectively. Publication bias was assessed using multiple methods.
Results A random effects mean correlation between self-control and deviance was Mr = 0.415 for cross-sectional studies and Mr = 0.345 for longitudinal ones; this effect did not significantly differ by study design. Studies with more male participants, studies based on older or US-based populations, and self-report studies found weaker effects.
Conclusions Substantial empirical support was found for the main argument of self-control theory and on the transdisciplinary link between self-control and measures of crime and deviance. In contrast to Pratt and Cullen, but consistent with theory, the effect from cross-sectional versus longitudinal studies did not significantly differ. There was no evidence of publication bias
Towards the Development of a Risk Model for Unmanned Vessels Design and Operations
An unmanned merchant vessel seems to be escaping from the stage of idea exploration. Once the concept proofs its safety, it may become a part of maritime reality. Although the safety aspect of such a ship has been addressed by a handful of scholars, the problem remains open. This is mainly due to lack of knowledge regarding actual operational circumstances and design of unmanned ships, which are yet to be developed. In the attempt of bridging this gap, the risk analysis associated with unmanned ships needs to be carried out, where all relevant hazards and consequences are assessed and quantified in systematic manner. In this paper we present the results of a first step of such analysis, namely the hazard analysis associated with the unmanned ships. The list of hazards covers various aspects of unmanned shipping originating from both design and operational phases of vessel’s life. Subsequently the hazards and related consequences are organized in a casual manner, resulting in the development of a structure of a risk model
Einstein-Podolsky-Rosen correlations of Dirac particles - quantum field theory approach
We calculate correlation function in the Einstein--Podolsky--Rosen type of
experiment with massive relativistic Dirac particles in the framework of the
quantum field theory formalism. We perform our calculations for states which
are physically interesting and transforms covariantly under the full Lorentz
group action, i.e. for pseudoscalar and vector state.Comment: 9 pages, 2 figures. Published versio
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