27,821 research outputs found
Unethical aspects of homeopathic dentistry
In the last year there has been a great deal of public debate about homeopathy, the system of alternative medicine whose main principles are that like cures like and that potency increases relative to dilution. The House of Commons Select Committee on Science and Technology concluded in November 2009 that there is no evidence base for homeopathy, and agreed with some academic commentators that homeopathy should not be funded by the NHS. While homeopathic doctors and hospitals are quite commonplace, some might be surprised to learn that there are also many homeopathic dentists practising in the UK. This paper examines the statements made by several organisations on behalf of homeopathic dentistry and suggests that they are not entirely ethical and may be in breach of various professional guidelines
Inhomogeneous Coupling in Two-Channel Asymmetric Simple Exclusion Processes
Asymmetric exclusion processes for particles moving on parallel channels with
inhomogeneous coupling are investigated theoretically. Particles interact with
hard-core exclusion and move in the same direction on both lattices, while
transitions between the channels is allowed at one specific location in the
bulk of the system. An approximate theoretical approach that describes the
dynamics in the vertical link and horizontal lattice segments exactly but
neglects the correlation between the horizontal and vertical transport is
developed. It allows us to calculate stationary phase diagrams, particle
currents and densities for symmetric and asymmetric transitions between the
channels. It is shown that in the case of the symmetric coupling there are
three stationary phases, similarly to the case of single-channel totally
asymmetric exclusion processes with local inhomogeneity. However, the
asymmetric coupling between the lattices lead to a very complex phase diagram
with ten stationary-state regimes. Extensive Monte Carlo computer simulations
generally support theoretical predictions, although simulated stationary-state
properties slightly deviate from calculated in the mean-field approximation,
suggesting the importance of correlations in the system. Dynamic properties and
phase diagrams are discussed by analyzing constraints on the particle currents
across the channels
A MAPPING OF EUROPEAN STUDIES EAST OF THE MISSISSIPPI: POLITICAL SCIENCE
The primary goal and mandate of this study are to
map the development of European Economic Community
(EEC), now European Union (EU) studies (EEC/EU) in
political science in the United States (US). The discussion
of EU studies in the US has been divided into two chapters
due to the large quantity of research this field has generated
in the US since 1958. This chapter concentrates on the
middle and eastern regions of the US where proximity to
Europe has promoted interest in European politics and
scholarship on European integration and EEC/EU development.
There is another chapter focusing primarily on
political science studies of the EU in the western US region,
and also a chapter on teaching the EU. The chapters
on political science scholarship focusing on the EU form
part of a larger body of scholarship mapping EU studies
around the world
Two-Channel Totally Asymmetric Simple Exclusion Processes
Totally asymmetric simple exclusion processes, consisting of two coupled
parallel lattice chains with particles interacting with hard-core exclusion and
moving along the channels and between them, are considered. In the limit of
strong coupling between the channels, the particle currents, density profiles
and a phase diagram are calculated exactly by mapping the system into an
effective one-channel totally asymmetric exclusion model. For intermediate
couplings, a simple approximate theory, that describes the particle dynamics in
vertical clusters of two corresponding parallel sites exactly and neglects the
correlations between different vertical clusters, is developed. It is found
that, similarly to the case of one-channel totally asymmetric simple exclusion
processes, there are three stationary state phases, although the phase
boundaries and stationary properties strongly depend on inter-channel coupling.
An extensive computer Monte Carlo simulations fully support the theoretical
predictions.Comment: 13 pages, 10 figure
Enhancing active vision system categorization capability through uniform local binary patterns
Previous research in Neuro-Evolution controlled Active Vision Systems has shown its potential to solve various shape categorization and discrimination problems. However, minimal investigation has been done in using this kind of evolved system in solving more complex vision problems. This is partly due to variability in lighting conditions, reflection, shadowing etc., which may be inherent to these kinds of problems. It could also be due to the fact that building an evolved system for these kinds of problems may be too computationally expensive. We present an Active Vision System controlled Neural Network trained by a Genetic Algorithm that can autonomously scan through an image pre-processed by Uniform Local Binary Patterns [8]. We demonstrate the ability of this system to categorize more complex images taken from the camera of a Humanoid (iCub) robot. Preliminary investigation results show that the proposed Uniform Local Binary Pattern [8] method performed better than the gray-scale averaging method of [1] in the categorization tasks. This approach provides a framework that could be used for further research in using this kind of system for more complex image problems
Theoretical Investigation of Totally Asymmetric Exclusion Processes on Lattices with Junctions
Totally asymmetric simple exclusion processes on lattices with junctions,
where particles interact with hard-core exclusion and move on parallel lattice
branches that at the junction combine into a single lattice segment, are
investigated. A simple approximate theory, that treats the correlations around
the junction position in a mean-field fashion, is developed in order to
calculate stationary particle currents, density profiles and a phase diagram.
It is shown that there are three possible stationary phases depending on the
state of each of the lattice branch. At first-order phase boundaries, where the
density correlations are important, a modified phenomenological domain-wall
theory, that accounts for correlations, is introduced. Extensive Monte Carlo
computer simulations are performed to investigate the system, and it is found
that they are in excellent agreement with theoretical predictions.Comment: 16 pages, 7 figure
Fractional generalization of Fick's law: a microscopic approach
In the study of transport in inhomogeneous systems it is common to construct
transport equations invoking the inhomogeneous Fick law. The validity of this
approach requires that at least two ingredients be present in the system.
First, finite characteristic length and time scales associated to the dominant
transport process must exist. Secondly, the transport mechanism must satisfy a
microscopic symmetry: global reversibility. Global reversibility is often
satisfied in nature. However, many complex systems exhibit a lack of finite
characteristic scales. In this Letter we show how to construct a generalization
of the inhomogeneous Fick law that does not require the existence of
characteristic scales while still satisfying global reversibility.Comment: 4 pages. Published versio
He 2-104: A link between symbiotic stars and planetary nebulae
Ultraviolet, optical and infrared observations of He 2-104 are presented, and estimates for some of the physical properties of the nebular shell are made. It is argued that He 2-104 is in transition between the D-type symbiotic star and bipolar planetary nebula phases and, as such, represents a link between subclasses of these two types of objects. The model includes a binary system with a Mira variable and a hot, evolved star. Previous mass loss has resulted in the formation of a disk of gas and dust around the whole system, while the hot star has an accretion disk which produces the observed highly ionized emission line spectrum. Emission lines from cooler, lower density gas is also observed to come from the nebula. In addition, matter is flowing out of the system in a direction perpendicular to the disk with a high velocity and is impacting upon the previously-ejected red giant wind and/or the ambient interstellar medium
Parallel Coupling of Symmetric and Asymmetric Exclusion Processes
A system consisting of two parallel coupled channels where particles in one
of them follow the rules of totally asymmetric exclusion processes (TASEP) and
in another one move as in symmetric simple exclusion processes (SSEP) is
investigated theoretically. Particles interact with each other via hard-core
exclusion potential, and in the asymmetric channel they can only hop in one
direction, while on the symmetric lattice particles jump in both directions
with equal probabilities. Inter-channel transitions are also allowed at every
site of both lattices. Stationary state properties of the system are solved
exactly in the limit of strong couplings between the channels. It is shown that
strong symmetric couplings between totally asymmetric and symmetric channels
lead to an effective partially asymmetric simple exclusion process (PASEP) and
properties of both channels become almost identical. However, strong asymmetric
couplings between symmetric and asymmetric channels yield an effective TASEP
with nonzero particle flux in the asymmetric channel and zero flux on the
symmetric lattice. For intermediate strength of couplings between the lattices
a vertical cluster mean-field method is developed. This approximate approach
treats exactly particle dynamics during the vertical transitions between the
channels and it neglects the correlations along the channels. Our calculations
show that in all cases there are three stationary phases defined by particle
dynamics at entrances, at exits or in the bulk of the system, while phase
boundaries depend on the strength and symmetry of couplings between the
channels. Extensive Monte Carlo computer simulations strongly support our
theoretical predictions.Comment: 16 page
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