20,958 research outputs found
Palindromic 3-stage splitting integrators, a roadmap
The implementation of multi-stage splitting integrators is essentially the
same as the implementation of the familiar Strang/Verlet method. Therefore
multi-stage formulas may be easily incorporated into software that now uses the
Strang/Verlet integrator. We study in detail the two-parameter family of
palindromic, three-stage splitting formulas and identify choices of parameters
that may outperform the Strang/Verlet method. One of these choices leads to a
method of effective order four suitable to integrate in time some partial
differential equations. Other choices may be seen as perturbations of the
Strang method that increase efficiency in molecular dynamics simulations and in
Hybrid Monte Carlo sampling.Comment: 20 pages, 8 figures, 2 table
The Dyer-Roeder relation in a universe with particle production
We have obtained analytical exact solutions of the Dyer-Roeder equation in a
cosmological model where creation of particles occurs at the expenses of the
gravitational field. We discussed the influences of inhomogeneities in the path
of a light beam on the apparent diameter of astrophysical objects and consider
both redshift independent as redshift dependent distributions of the
inhomogeneities.Comment: 7 pages, 4 figures. Accepted to be published in the Astronomy and
Astrophysics Journa
Redundancy of stereoscopic images: Experimental Evaluation
With the recent advancement in visualization devices over the last years, we
are seeing a growing market for stereoscopic content. In order to convey 3D
content by means of stereoscopic displays, one needs to transmit and display at
least 2 points of view of the video content. This has profound implications on
the resources required to transmit the content, as well as demands on the
complexity of the visualization system. It is known that stereoscopic images
are redundant, which may prove useful for compression and may have positive
effect on the construction of the visualization device. In this paper we
describe an experimental evaluation of data redundancy in color stereoscopic
images. In the experiments with computer generated and real life and test
stereo images, several observers visually tested the stereopsis threshold and
accuracy of parallax measuring in anaglyphs and stereograms as functions of the
blur degree of one of two stereo images and color saturation threshold in one
of two stereo images for which full color 3D perception with no visible color
degradations is maintained. The experiments support a theoretical estimate that
one has to add, to data required to reproduce one of two stereoscopic images,
only several percents of that amount of data in order to achieve stereoscopic
perception
Creating agent platforms to host agent-mediated services that share resources
After a period where the Internet was exclusively filled with content,
the present
efforts are moving towards services, which handle the raw information to
create
value from it. Therefore labors to create a wide collection of
agent-based services
are being perfomed in several projects, such as Agentcities does.
In this work we present an architecture for agent platforms named
a-Buildings. The
aim of the proposed architecture is to ease the creation, installation,
search and
management of agent-mediated services and the share of resources among
services.
To do so the a-Buildings architecture creates a new level of abstraction
on top of
the standard FIPA agent platform specification.
Basically, an a-Building is a service-oriented platform which offers a
set of
low level services to the agents it hosts. We define low level services
as those
required services that are neccesary to create more complex high level
composed
services.Postprint (published version
Zastosowanie programu gwarancji dla zdrowia jamy ustnej w opiece nad kobietą w ciąży w rodzinnym centrum zdrowia w Concepción, Chile, w latach 2014–2015
Indexación: Scopus.Background. Oral health plays a crucial role in general health, quality of life and well-being of pregnant women and their newborns. In Chile, pregnant women have dental care guaranteed by law. However, due to the lack of previous epidemiological studies on the benefits of this guarantee, it is necessary to describe this situation and evaluate the need to change the methods of providing dental services. Objectives. The objective of this study was to describe the pattern of providing dental benefits resulting from the Explicit Health Guarantee – Integral Oral Health in Pregnant Women (GES-SOIE) program to pregnant women attending the Juan Soto Fernández Family Health Center, Concepción, Chile, in 2014–2015. Material and methods. A cross-sectional study of the electronic dental records of patients admitted to GES-SOIE was conducted. The variables studied were sociodemographic data, dental chair hours, non-attendance, treatment completion, and the type of referral to secondary healthcare (SHC). Results. Of 233 pregnant women, 65.2% were registered for non-attendance, 21.2% required referral to SHC and 76.4% completed their treatment. When performing logistic regression, it was found that for each non-attendance the chance of not completing the treatment increased 1.4 times. Conclusions. The level of non-attendance and opting out of the treatment in pregnant women is high, which hinders the proper functioning and effectiveness of GES-SOIE. © 2018 by Wroclaw Medical University and Polish Dental Society.http://www.dmp.umed.wroc.pl/en/article/2018/55/2/179
Constraining Elko Dark Matter at the LHC with Monophoton Events
A mass dimension one fermion, also known as Elko, constitutes a dark matter
candidate which might interact with photons at the tree level in a specific
fashion. In this work, we investigate the constraints imposed by unitarity and
LHC data on this type of interactions using the search for new physics in
monophoton events. We found that Elkos which can explain the dark matter relic
abundance mainly through electromagnetic interactions are excluded at the
95\%CL by the 8 TeV LHC data for masses up to 1 TeV.Comment: 6 pages, 4 figure
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