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HLA-B27 Positivity: associated health implications
HLA-B27 positivity makes the onset of autoimmune diseases such as uveitis, ankylosing spondylitis and Crohn's disease more likely to occur. Ankylosing spondylitis and Crohn's disease are two types of HLA-B27 positive diseases that demonstrate a direct association with uveitis. Although the possession of HLA-B27 positivity is not mandatory for autoimmune diseases such as uveitis to occur, HLA-B27 positivity not only makes it more likely but may modify the clinical picture in which a patient presents. In relation to assessment and diagnosis it is imperative that the medical history of patients is thoroughly examined to ensure pathological sequelae are appropriately treated. Nurses play an important role in assessing patients that have uveitis and should suspect ankylosing spondylitis or Crohn's disease may be present
Ordering dynamics of the driven lattice gas model
The evolution of a two-dimensional driven lattice-gas model is studied on an
L_x X L_y lattice. Scaling arguments and extensive numerical simulations are
used to show that starting from random initial configuration the model evolves
via two stages: (a) an early stage in which alternating stripes of particles
and vacancies are formed along the direction y of the driving field, and (b) a
stripe coarsening stage, in which the number of stripes is reduced and their
average width increases. The number of stripes formed at the end of the first
stage is shown to be a function of L_x/L_y^\phi, with \phi ~ 0.2. Thus,
depending on this parameter, the resulting state could be either single or
multi striped. In the second, stripe coarsening stage, the coarsening time is
found to be proportional to L_y, becoming infinitely long in the thermodynamic
limit. This implies that the multi striped state is thermodynamically stable.
The results put previous studies of the model in a more general framework
Marginalising instrument systematics in HST WFC3 transit lightcurves
Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) infrared observations
at 1.1-1.7m probe primarily the HO absorption band at 1.4m, and
has provided low resolution transmission spectra for a wide range of
exoplanets. We present the application of marginalisation based on Gibson
(2014) to analyse exoplanet transit lightcurves obtained from HST WFC3, to
better determine important transit parameters such as R/R, important
for accurate detections of HO. We approximate the evidence, often referred
to as the marginal likelihood, for a grid of systematic models using the Akaike
Information Criterion (AIC). We then calculate the evidence-based weight
assigned to each systematic model and use the information from all tested
models to calculate the final marginalised transit parameters for both the
band-integrated, and spectroscopic lightcurves to construct the transmission
spectrum. We find that a majority of the highest weight models contain a
correction for a linear trend in time, as well as corrections related to HST
orbital phase. We additionally test the dependence on the shift in spectral
wavelength position over the course of the observations and find that
spectroscopic wavelength shifts , best describe the
associated systematic in the spectroscopic lightcurves for most targets, while
fast scan rate observations of bright targets require an additional level of
processing to produce a robust transmission spectrum. The use of
marginalisation allows for transparent interpretation and understanding of the
instrument and the impact of each systematic evaluated statistically for each
dataset, expanding the ability to make true and comprehensive comparisons
between exoplanet atmospheres.Comment: 19 pages, 13 figures, 8 tables, Accepted to Ap
Factorised steady states for multi-species mass transfer models
A general class of mass transport models with Q species of conserved mass is
considered. The models are defined on a lattice with parallel discrete time
update rules. For one-dimensional, totally asymmetric dynamics we derive
necessary and sufficient conditions on the mass transfer dynamics under which
the steady state factorises. We generalise the model to mass transfer on
arbitrary lattices and present sufficient conditions for factorisation. In both
cases, explicit results for random sequential update and continuous time limits
are given.Comment: 11 page
Negations in syllogistic reasoning: Evidence for a heuristic–analytic conflict
An experiment utilizing response time measures was conducted to test dominant processing strategies in syllogistic reasoning with the expanded quantifier set proposed by Roberts (2005). Through adding negations to existing quantifiers it is possible to change problem surface features without altering logical validity. Biases based on surface features such as atmosphere, matching, and the probability heuristics model (PHM; Chater & Oaksford, 1999; Wetherick & Gilhooly, 1995) would not be expected to show variance in response latencies, but participant responses should be highly sensitive to changes in the surface features of the quantifiers. In contrast, according to analytic accounts such as mental models theory and mental logic (e.g., Johnson-Laird & Byrne, 1991; Rips, 1994) participants should exhibit increased response times for negated premises, but not be overly impacted upon by the surface features of the conclusion. Data indicated that the dominant response strategy was based on a matching heuristic, but also provided evidence of a resource-demanding analytic procedure for dealing with double negatives. The authors propose that dual-process theories offer a stronger account of these data whereby participants employ competing heuristic and analytic strategies and fall back on a heuristic response when analytic processing fails
The Effect of Weak Interactions on the Ultra-Relativistic Bose-Einstein Condensation Temperature
We calculate the ultra-relativistic Bose-Einstein condensation temperature of
a complex scalar field with weak lambda Phi^4 interaction. We show that at high
temperature and finite density we can use dimensional reduction to produce an
effective three-dimensional theory which then requires non-perturbative
analysis. For simplicity and ease of implementation we illustrate this process
with the linear delta expansion.Comment: Latex2e, 12 pages, three eps figures, replacement with additional
discussion and extra figur
Condensation Transitions in Two Species Zero-Range Process
We study condensation transitions in the steady state of a zero-range process
with two species of particles. The steady state is exactly soluble -- it is
given by a factorised form provided the dynamics satisfy certain constraints --
and we exploit this to derive the phase diagram for a quite general choice of
dynamics. This phase diagram contains a variety of new mechanisms of condensate
formation, and a novel phase in which the condensate of one of the particle
species is sustained by a `weak' condensate of particles of the other species.
We also demonstrate how a single particle of one of the species (which plays
the role of a defect particle) can induce Bose-Einstein condensation above a
critical density of particles of the other species.Comment: 17 pages, 4 Postscript figure
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