904 research outputs found
Automatic Filters for the Detection of Coherent Structure in Spatiotemporal Systems
Most current methods for identifying coherent structures in
spatially-extended systems rely on prior information about the form which those
structures take. Here we present two new approaches to automatically filter the
changing configurations of spatial dynamical systems and extract coherent
structures. One, local sensitivity filtering, is a modification of the local
Lyapunov exponent approach suitable to cellular automata and other discrete
spatial systems. The other, local statistical complexity filtering, calculates
the amount of information needed for optimal prediction of the system's
behavior in the vicinity of a given point. By examining the changing
spatiotemporal distributions of these quantities, we can find the coherent
structures in a variety of pattern-forming cellular automata, without needing
to guess or postulate the form of that structure. We apply both filters to
elementary and cyclical cellular automata (ECA and CCA) and find that they
readily identify particles, domains and other more complicated structures. We
compare the results from ECA with earlier ones based upon the theory of formal
languages, and the results from CCA with a more traditional approach based on
an order parameter and free energy. While sensitivity and statistical
complexity are equally adept at uncovering structure, they are based on
different system properties (dynamical and probabilistic, respectively), and
provide complementary information.Comment: 16 pages, 21 figures. Figures considerably compressed to fit arxiv
requirements; write first author for higher-resolution version
Experimental Study of the Shortest Reset Word of Random Automata
In this paper we describe an approach to finding the shortest reset word of a
finite synchronizing automaton by using a SAT solver. We use this approach to
perform an experimental study of the length of the shortest reset word of a
finite synchronizing automaton. The largest automata we considered had 100
states. The results of the experiments allow us to formulate a hypothesis that
the length of the shortest reset word of a random finite automaton with
states and 2 input letters with high probability is sublinear with respect to
and can be estimated as $1.95 n^{0.55}.
ICON 2019: International Scientific Tendinopathy Symposium Consensus: Clinical Terminology
© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.Background Persistent tendon pain that impairs function has inconsistent medical terms that can influence choice of treatment.1 When a person is told they have tendinopathy by clinician A or tendinitis by clinician B, they might feel confused or be alarmed at receiving what they might perceive as two different diagnoses. This may lead to loss of confidence in their health professional and likely adds to uncertainty if they were to search for information about their condition. Clear and uniform terminology also assists inter-professional communication. Inconsistency in terminology for painful tendon disorders is a problem at numerous anatomical sites. Historically, the term ‘tendinitis’ was first used to describe tendon pain, thickening and impaired function (online supplementary figure S1). The term ‘tendinosis’ has also been used in a small number of publications, some of which were very influential.2 3 Subsequently, ‘tendinopathy’ emerged as the most common term for persistent tendon pain.4 5 To our knowledge, experts (clinicians and researchers) or patients have never engaged in a formal process to discuss the terminology we use. We believe that health professionals have not yet agreed on the appropriate terminology for painful tendon conditions.Peer reviewedFinal Accepted Versio
Results on correlations and fluctuations from NA49
The large acceptance and high momentum resolution as well as the significant
particle identification capabilities of the NA49 experiment at the CERN SPS
allow for a broad study of fluctuations and correlations in hadronic
interactions. In the first part recent results on event-by-event charge and p_t
fluctuations are presented. Charge fluctuations in central Pb+Pb reactions are
investigated at three different beam energies (40, 80, and 158 AGeV), while for
the p_t fluctuations the focus is put on the system size dependence at 158
AGeV. In the second part recent results on Bose Einstein correlations of h-h-
pairs in minimum bias Pb+Pb reactions at 40 and 158 AGeV, as well as of K+K+
and K-K- pairs in central Pb+Pb collisions at 158 AGeV are shown. Additionally,
other types of two particle correlations, namely pi p, Lambda p, and Lambda
Lambda correlations, have been measured by the NA49 experiment. Finally,
results on the energy and system size dependence of deuteron coalescence are
discussed.Comment: 10 pages, 12 figures, Presented at Quark Matter 2002, Nantes, France,
Corrected error in Eq.
Event-by-event fluctuations of average transverse momentum in central Pb+Pb collisions at 158 GeV per nucleon
We present first data on event-by-event fluctuations in the average
transverse momentum of charged particles produced in Pb+Pb collisions at the
CERN SPS. This measurement provides previously unavailable information allowing
sensitive tests of microscopic and thermodynamic collision models and to search
for fluctuations expected to occur in the vicinity of the predicted QCD phase
transition. We find that the observed variance of the event-by-event average
transverse momentum is consistent with independent particle production modified
by the known two-particle correlations due to quantum statistics and final
state interactions and folded with the resolution of the NA49 apparatus. For
two specific models of non-statistical fluctuations in transverse momentum
limits are derived in terms of fluctuation amplitude. We show that a
significant part of the parameter space for a model of isospin fluctuations
predicted as a consequence of chiral symmetry restoration in a non-equilibrium
scenario is excluded by our measurement.Comment: 6 pages, 2 figures, submitted to Phys. Lett.
Event-by-event fluctuations of the kaon to pion ratio in central Pb+Pb collisions at 158 GeV per Nucleon
We present the first measurement of fluctuations from event to event in the
production of strange particles in collisions of heavy nuclei. The ratio of
charged kaons to charged pions is determined for individual central Pb+Pb
collisions. After accounting for the fluctuations due to detector resolution
and finite number statistics we derive an upper limit on genuine
non-statistical fluctuations, perhaps related to a first or second order QCD
phase transition. Such fluctuations are shown to be very small.Comment: 4 pages, 2 figure
Bose-Einstein Correlations of Charged Kaons in Central Pb+Pb Collisions at
Bose-Einstein correlations of charged kaons were measured near mid-rapidity
in central Pb+Pb collisions at 158 AGeV by the NA49 experiment at the
CERN SPS. Source radii were extracted using the Yano-Koonin-Podgoretsky and
Bertsch-Pratt parameterizations. The results are compared to published pion
data. The measured dependence for kaons and pions is consistent with
collective transverse expansion of the source and a freeze-out time of about
9.5 .Comment: 14 pages with 7 figures, submitted to Phys. Lett.
Alcohol and mouth cancer
There is now considered to be no safe limit for alcohol intake. Studies have shown that risk of mouth cancer increases with greater alcohol intake (in particular when associated with the use of tobacco). This paper reviews the role for alcohol in the aetiology of mouth cancer both in terms of how it may give rise to cancerous change and the relative risk it carries (arising from various systematic and meta-analyses reported over the last decade). While obtaining a reliable alcohol history can be problematic (with under reporting frequently suspected) greater awareness of the role of alcohol in both local and systemic disease (in particular that of cancer in an ever increasing number of sites) may serve as a motivator for behaviour change within our patients. To that end patients should be aware of the alcohol content in the drinks they consume and consider recording their alcohol intake over a defined period (eg, use of a diary or app over a two to four week period)
Two-proton correlations from 158 AGeV Pb+Pb central collisions
The two-proton correlation function at midrapidity from Pb+Pb central
collisions at 158 AGeV has been measured by the NA49 experiment. The results
are compared to model predictions from static thermal Gaussian proton source
distributions and transport models RQMD and VENUS. An effective proton source
size is determined by minimizing CHI-square/ndf between the correlation
functions of the data and those calculated for the Gaussian sources, yielding
3.85 +-0.15(stat.) +0.60-0.25(syst.) fm. Both the RQMD and the VENUS model are
consistent with the data within the error in the correlation peak region.Comment: RevTeX style, 6 pages, 4 figures, 1 table. More discussion are added
about the structure on the tail of the correlation function. The systematic
error is revised. To appear in Phys. Lett.
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